ZHAW ICP Research Report 2015 by ZHAW School of Engineering

Research Report 2015

Zurich Universities of Applied Sciences and Arts

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Research & Development

Simulated intensity of scattered light above a rough Zinc Oxide surface used for optimizing solar cells. The lateral size is 4.5 um and the wavelength is 600 nm.

Simulierte Lichtintensität gestreut durch eine raue Zinkoxid Oberfläche für die Optimierung von Solarzellen. Die Kantenlänge ist 4.5 um und die Wellenlänge ist 600 nm.

Contents Preface

Vorwort

Projects

1.1 Komfortables Reisen durch Erfassung, Analyse und Postprocessing von 3D Daten zur Gleisvermessung . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2 Mathe sch체tzt den Menschen in der Masse . . . . . . . . . . . . . . . . . . . . . . .

1.3 Liquid water modeling in PEMFC porous layers . . . . . . . . . . . . . . . . . . . . .

1.4 Multi-phase modelling of a hydrogen generator . . . . . . . . . . . . . . . . . . . . .

1.5 Electrical losses in hematite during photoelectrolysis . . . . . . . . . . . . . . . . . .

1.6 Development and optimization of patterned porous materials for thermo-neutral fuel cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.7 Towards the detailed understanding of coffee brewing . . . . . . . . . . . . . . . . . 11 1.8 Improved cooling processes for chocolate production . . . . . . . . . . . . . . . . . . 12 1.9 Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.10 New generation of high-performance air heaters . . . . . . . . . . . . . . . . . . . . 14 1.11 Numerical Simulation of Stacked OLEDs and Solar Cells . . . . . . . . . . . . . . . . 15 1.12 LED-based sun simulator for solar cell characterization . . . . . . . . . . . . . . . . . 16 1.13 Impact of sand content on solute diffusion in Opalinus Clay . . . . . . . . . . . . . . 17 1.14 Fast transient simulation of semiconductor devices . . . . . . . . . . . . . . . . . . . 18 1.15 CARDYN - Charge carrier dynamics in organic electronic devices . . . . . . . . . . . 19 1.16 Fluxim Research and Development Support . . . . . . . . . . . . . . . . . . . . . . . 20 1.17 Electrical interconnections in solar cells and modules . . . . . . . . . . . . . . . . . . 21 1.18 Rigorous simulation of light scattering . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1.19 Simulation of heat transfer processes within a fuel cell system based on OpenFoam

1.20 Tentative modelling of the failure in Solid Oxide Fuel Cell . . . . . . . . . . . . . . . . 24 1.21 A model-based optimization of cooling tunnel processes . . . . . . . . . . . . . . . . 25 1.22 Simulation Software for DSSC Modules . . . . . . . . . . . . . . . . . . . . . . . . . 26 1.23 Coulometric system with generator cell . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.24 Euler-Lagrangian model of particle laden flows and deposition effects in powder coating

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.25 Simulation von Heizelementen f체r Heissluftgebl채se . . . . . . . . . . . . . . . . . . . 29 1

Institute of Computational Physics

Research Report 2015

1.26 Optimierung von porösen Diaphragmen Modell- und simulationsunterstützte Materialentwicklung . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.27 Simulation des Nano-Dosierverhaltens von nicht-Newtonschen Flüssigkeiten . . . . 31 1.28 Nondestructive Quality and Process Control of Thermal Spray Coatings . . . . . . . 32 1.29 Pulverbeschichten mit Closed-Loop Regelung . . . . . . . . . . . . . . . . . . . . . . 33 1.30 Qualitätssicherung von Haftvermittlerschichtdicken in der Produktion von Drehschwingungsdämpfern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 1.31 Entwicklung eines Messgeräts für die praktische Anwendung der Thermischen Schichtprüfung an Kunst und Kulturgut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 1.32 Blaues Licht aus neuen Materialien . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 1.33 Herstellung von Perowskit-Solarzellen . . . . . . . . . . . . . . . . . . . . . . . . . . 37 1.34 Modellbasierter Reglerentwurf für die Temperaturregelung eines Kryostaten . . . . . 38 Appendix

A.1 Student Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 A.2 Scientific Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 A.3 Book Chapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 A.4 News Articles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 A.5 Conferences and Workshops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 A.6 Public Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 A.7 Patents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 A.8 Prizes and Awards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 A.9 Teaching

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

A.10 Spin-off Companies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 A.11 ICP-Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 A.12 Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

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Zürcher Fachhochschule

Research Report 2015

Institute of Computational Physics

Preface In a February 2015 e-mail, Beat Ruhstaller included a postscript: By the way, we are looking for the successor to my successor. In saying so, he wanted to draw my attention to the ICP’s recent announcement of a competition for their head position. At the time, I considered myself lucky to be the managing director of the company Vela Solaris and I had certainly not been looking for a new job. Beat and I had been close friends for a long time, thus giving me the opportunity to get to know the ICP. Like déjà-vu, Beat’s suggestion came as an incredibly tempting second chance: 12 years before, Beat had spoken to me about Fluxim, asking if I wanted to play an active role in establishing and organising the company with him. Though I declined his offer at the time, I felt a slight pang of regret shortly thereafter. In those days I had two options: the organic LED at the University of Applied Sciences in Winterthur, or a similar research opportunity at the Institute for Solar Technology SPF in Rapperswil. Both offered the potential for subsequent spin-off projects, and a simulation algorithm had twice been at the core of innovation. Thanks to my former expertise in the optoelectronic-modeling field, I felt more confident with Beat’s field; nevertheless, I brought myself to finally take a slightly bigger step into the solar energy field. I was certain that renewable energy sources would have become an important issue and that designing physics-based simulation software would have contributed to the greater success of solar systems. Thus, at the end of 2006 I co-founded the company Vela Solaris in Rapperswil with the team of the long-standing college project called Polysun. We were lucky with our timing, as we entered the market in a prime position for the energy revolution to come. Instead of marketing our engineering services, we decided to sell our software licenses internationally. Today, Vela Solaris is a stable company whose simulation software Polysun is wellpositioned in the market, acting as a planning tool for several tens of thousands of active users. During the course of the company’s history, its innovative projects have been of fundamental importance, helping the software against rival products. And so, since October 2015 I have been the Head of the ICP. We found a qualified replacement for the management of Vela Solaris. I granted the ICP my network and access to the Polysun source code. Some of Polysun’s innovative projects in recent years have been highly researchoriented and have had to be put on hold. These projects have now found their respective niches within the framework of the ICP’s multiphysics-modeling focus and the greater energy field from the School of Engineering (SoE). Talks with our hardware partners are already under way, but our vision is fortunately focused on the long term. As far as Bachelor’s theses are concerned, we have already tackled various topics. Moreover, ICP has a tradition of proffering ambitious projects and supporting students through various spin-off companies, thereby giving them the opportunity to perform excellently within a short working period. Interestingly, these research projects have been accompanied by new synergies in teaching projects, built upon my previous work experience: for years now, Vela Solaris has offered continuing education and has become involved in vocational education and in working with technical colleges. I can directly implement the results of such experiences to the ZHAW teaching. Thanks to computer simulation, a common feature throughout my career, I feel like my current position at ICP is exactly the right one. I find the diversity of the work fields really stimulating. In my opinion, spearheading the core of these applications within the framework of modeling and numerics is an important communication task. Alongside the simulation experience, its practical applications are also crucial: valuable contributions to different areas have only been achieved thanks to good industrial partners. Finally, and importantly, innovation capacity sometimes rests on thinking out of the box and bringing together different branches of knowledge. I would like to sincerely thank Beat for thinking of me one year ago. That one line in his e-mail back then was a perfect example of spontaneously thinking out of the box. Thanks also to the ICP team for their warm welcome and sound support during my period of vocational adjustment. Congratulations on your achievements and their presentation in this annual report ! Andreas Witzig, February 2016

Zürcher Fachhochschule

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Institute of Computational Physics

Research Report 2015

Vorwort Im Februar 2015 hatte Beat Ruhstaller im PS einer E-Mail geschrieben, Übrigens, wir suchen den Nachfolger meines Nachfolgers, und machte mich damit auf die Ausschreibung der ICPInstitutsleiterposition aufmerksam. Ich war damals als Geschäftsführer der Firma Vela Solaris glücklich mit meinem Job und überhaupt nicht auf Stellensuche. Mit Beat verbindet mich eine langjährige Freundschaft und dadurch hatte ich auch das ICP bereits kennen gelernt. Beats Hinweis war für mich ein Déja-Vu und eine unglaublich interessante zweite Chance: Vor 12 Jahren hatte mir Beat von Fluxim erzählt und mich angefragt, ob ich bei der Firmengründung aktiv mitwirken und mit ihm zusammen die Firma aufbauen möchte. Ich hatte ihm damals abgesagt und dem Entscheid noch einige Zeit etwas nachgetrauert. Ich hatte damals zwei Optionen: neben dem Thema Organische LED an der Fachhochschule in Winterthur gab es am Solartechnik-Institut SPF der Hochschule Rapperswil ein ähnliches Angebot. Bei beiden bot sich die Chance für eine spätere Spin-Off Gründung und zweimal war ein Simulationsalgorithmus Kern der Innovation. Obwohl ich mit meinem damaligen Arbeitsgebiet Optoelektronik-Modellierung in Beats Thema besser verwurzelt war, hatte ich mich letztlich für den etwas grösseren Sprung in das neue Anwendungsgebiet Solarenergie gewagt. Ich war überzeugt, dass erneuerbare Energiequellen zu einem grossen Thema werden sollten und dass eine auf physikalischer Simulation basierende Planungssoftware einen Beitrag zur Verbreitung von Solaranlagen liefern könnte. Mit dem Team des langjährigen Hochschulprojektes Polysun hatte ich dann in Rapperswil Ende 2006 die Firma Vela Solaris gegründet. Wir hatten Glück mit dem Timing und konnten uns gut positionieren für die darauf folgenden Energiewende-Jahre. Wir hatten uns entschieden, nicht unsere Ingenieurleistung sondern Softwarelizenzen international zu verkaufen. Inzwischen ist Vela Solaris ein stabiles Unternehmen und die Simulationssoftware Polysun mit mehreren zehntausend aktiven Nutzern als Planungswerkzeug gut im Markt verankert. Während der ganzen Firmengeschichte haben Innovationsprojekte eine zentrale Rolle gespielt und der Software zu einem Vorteil gegenüber der Konkurrenz verholfen. Nun bin ich seit Oktober 2015 Institutsleiter des ICP. Für die Geschäftsleitung von Vela Solaris hatten wir einen guten Nachfolger gefunden. Mein Netzwerk und den Zugang zum Polysun Quellcode bringe ich mit ans ICP. Bei den Polysun-Innovationsprojekten gab es in den letzten Jahren einige, die zu starken Forschungscharakter hatten und deshalb zurückgestellt werden mussten. Im ICP-Schwerpunkt Multiphysik-Modellierung und dem übergeordneten SoE-Thema Energie haben diese Projekte nun den idealen Rahmen gefunden. Die Gespräche mit den entsprechenden Hardwarepartnern laufen bereits, aber zum Glück haben wir hier einen langfristigen Horizont. Auf Stufe Bachelorarbeiten haben wir bereits mehrere Themen in Angriff genommen. Ich konnte dabei an die ICP-Tradition anknüpfen, ehrgeizige Arbeiten auszuschreiben und die Studenten mit Unterstützung der Spin-Off Firmen auf ein Niveau zu bringen, auf welchem sie in der kurzen Dauer der Arbeit Grossartiges leisten können. Neben den Forschungsprojekten bieten sich interessanterweise in der Lehre weitere Synergien zu meiner früheren Tätigkeit: Vela Solaris bietet schon seit Jahren Weiterbildung an und engagiert sich in der Berufsbildung und an Fachhochschulen. Die Erfahrungen daraus kann ich in der ZHAW-Lehre direkt umsetzen. Mit der Computersimulation als Klammer über meine berufliche Laufbahn bin ich nun am ICP genau am richtigen Ort angekommen. Neu und aufregend ist für mich die Vielfalt der Arbeitsgebiete. Ich sehe es als wichtige Kommunikationsaufgabe, den gemeinsamen Kern dieser Anwendungen in der Modellierung und der Numerik aufzuzeigen. Neben der Simulationserfahrung ist dabei die Verbindung zur Anwendung entscheidend. Nur mit guten Industriepartnern können in den vielen Themen wertvolle Beiträge geleistet werden. Und nicht zuletzt liegt die Innovationskraft auch darin, dass man über den Tellerrand schaut, manchmal out of the box denkt und die verschiedenen Disziplinen miteinander verbindet. Gerne möchte ich Beat danken, dass er vor einem Jahr an mich gedacht hat. Die Zeile im E-Mail von damals war ein typisches Beispiel für spontanes thinking out of the box. Danke auch dem ICPTeam für den herzlichen Empfang und die gute Unterstützung während meiner Einarbeitungszeit. Gratulation für die Erfolge und deren Präsentation im vorliegenden Jahresbericht ! Andreas Witzig, Februar 2016 www.zhaw.ch

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Research Report 2015

1.1

Institute of Computational Physics

Komfortables Reisen durch Erfassung, Analyse und Postprocessing von 3D Daten zur Gleisvermessung

Wir alle wünschen uns eine zuverlässige und leistungsfähige Verkehrsinfrastruktur; insbesondere im Bahnbereich. Damit Bahngesellschaften dies ermöglichen können benötigen sie ein umfassendes Infrastrukturdatenmanagement, zuverlässige Qualitätskontrollen im Bauprozess sowie die umfassende Kenntnis über den Zustand und die Anforderungen an das Streckennetz Contributors:

R. Axthelm

Partners: Funding: Duration:

IMS, Amberg Technologies KTI 2013–2016

Fig. 1: IMU gestützte Gleisvermessung, Bildquelle: http://www.ambergtechnologies.ch.

ARTIS ist ein neuartiges Informationssystem zur Erfassung und Analyse von 3D Daten zur Gleisvermessung. 3D Scandaten werden mit Daten aus bildgebenden Sensoren überlagert und gleisspezifische Parameter werden berechnet. Diese Verfahren sollen auch angewendet werden, falls die Messdaten aus einem Drittsystem stammen. Außerdem soll ARTIS Anwendungsfälle der Gleisvermessung abdecken, bei denen nur unvollständige Designdaten vorliegen. Die aktuellen Anwendungen stützen sich zum Beispiel auf die Verfügbarkeit von Designelementen, die allerdings nicht immer zur Verfügung stehen. Zusammen mit dem ICP werden unter Verwen-

dung geeigneter, mathematischer Methoden Softwarekomponenten entwickelt, die in der Lage sind aus einer Schienenachse die passenden Designelemente, das sind Geraden, Klothoiden Kreisund Parabelbögen, zu berechnen. Die Schienenachse selbst ist durch eine IMU gestützte Gleismessmethode ermittelt worden und liegt in Form von verrauschten Daten vor. Dieser Teil der Software berechnet Designelemente, die bestmöglich den Verlauf der vermessenen Trasse abzeichnet. Diese neuen Berechnungsverfahren kommen zur Anwendung bei der Erneuerung bzw. Wartung bestehender Eisenbahntrassen. Insbesondere auch dort, wo vorgängig keine Plandaten vorliegen.

2200 2150 2100 2050 2000 -1687

-1487

-1287

-1087

-887

-687

-487

-287

-87

113

313

Fig. 2: Automatisierte Designelementberechnung aus den verrauschten Trassenpositionsdaten.

Zürcher Fachhochschule

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Institute of Computational Physics

1.2

Research Report 2015

Mathe schützt den Menschen in der Masse

Wie können wir Gefahren bei Großveranstaltungen verhindern? gehört zu den drängenden Fragen unserer Zeit. Ein Interesse, dass Jedermann im öffentlichen Raum, insbesondere die Verantwortlichen wie Polizei, Veranstalter und Raumplaner haben. Zusammen mit der Zürcher ASE GmbH entwickelt das ICP präzise Modellrechnungen und eine Simulationssoftware für Menschenströme. Contributors:

R. Axthelm

Partners: Funding: Duration:

ASE GmbH KTI 2013–2016

Fig. 1: Selbst bei einer gewöhnlichen Leerung eines Stadions kann es allein durch das Aufkommen hoher Dichten an manchen Stellen zu einer erhöhten Panikgefahr kommen, Quelle: http://research.ptvgroup.com.

dellierungsparameter dient, Fig. 2. Der Vorteil an dieser Stelle besteht in der Möglichkeit der Einflussnahme auf die bestehende Situation aus Benutzersicht. Derzeit werden Validierungsrechnungen bezüglich Evakuierungszeiten durchgeführt. Zugrunde liegen experimentelle Daten des IAS (Forschungszentrum Jülich). Umgekehrt lässt sich durch pFlow ermitteln welche Charakteristika einer analytischen Beschreibung des Fundamentaldiagramms spezifische Situationen qualitativ und quantitativ gut abbilden.

Jeder kennt das beklemmende Gefühl, wenn man dichtgedrängt und bewegungsunfähig in einer Menschenansammlung verharren muss, so dass man kaum atmen kann; etwa vor einer Konzertbühne, beim Verlassen der Tribüne eines Stadions oder in einer Großstadt-U-Bahn während der rushhour. Dies motivierte uns, zusammen mit der Firma ASE GmbH, eine entsprechende Simulationssoftware zu entwickeln. Die Software pFlow basiert auf einem makroskopischen Modellansatz. Das heißt, dass eine Menge von Personen als Kontinuum aufgefasst wird, bei der nicht die Bewegung jedes Einzelnen im Fokus steht, sondern die zu jedem Zeitpunkt resultierende Dichteverteilung. Basierend auf dem Modellansatz 1 ∇Φ = 0 , |∇Φ| = , %t − ∇ · % f (%) |∇Φ| f (%)

1.8 1.6 1.4

Geschwindigkeit

1.2

wie er bisher in der Literatur zu diesem Thema zu finden ist, wurde eine Modellbeschreibung erarbeitet, die in gewissem Sinne das Ähnliche berechnet, numerisch aber stabiler ist. Die neuen Gleichungen werden in Kürze in [1] publiziert werden. % beschreibt die Dichteverteilung im Raum und ∇Φ die Bewegungsrichtung. Das sogenannte Fundamentaldiagramm f (%) liefert die dichteabhängige Geschwindigkeit von Fußgängern, die aus empirischen Daten ermittelt wird und als Mo-

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1 0.8 0.6 0.4 0.2 0 0

Dichte

Fig. 2: f (%) (—) ermittelt aus empirischen Daten (◦).

Literature: [1] R. Axthelm, Traffic and Granular Flow ’15, Springer, accepted.

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Research Report 2015

1.3

Institute of Computational Physics

Liquid water modeling in PEMFC porous layers

For a successful commercialization of polymer electrolyte fuel cell (PEFC), a high specific power output must be achieved. In this workpackage, as a part of the project funded by the Swiss National Science Foundation and the Swiss Federal Office of Energy, we aim at simulating the pore-scale water distribution in a fuel cell as to improve the parameterization of the transport properties and improve the macroscopic modeling of the device. Contributors:

J. Schumacher, L. Capone, J. Dujc, P. Marmet, A. Lamibrac, F. Büchi

Partners: Funding: Duration:

Paul Scherrer Institute SNSF, Swiss Federal Office of Energy 2014–2017 MC simulations at different water saturation levels were applied by using the experimentally determined pore structure. Also virtual structures, generated by the GeoDict software have been used as geometric input for the algorithm. The results are encouraging: we can simulate the water distribution using the energy minimization procedure (see Figures).

In order to improve the performance of polymer electrolyte fuel cells, the effect of the liquid water blocking the pores of the Gas Diffusion Layer (GDL) must be mitigated. Macro-homogeneous models treat a porous medium as an effective continuum involving volume-averaged quantities to find transport parameters such as permeability and conductivity, while the effect of the water hindering the pores occurs at a lower scale.

Fig. 2: Simulated 2D water distribution (blue) in the same solid (brown) porous structure as in Fig. 1.

Fig. 1: Experimental 2D water distribution (blue) in a solid (brown) porous structure obtained from a imbibition experiment [4].

We implemented a Monte Carlo (MC) algorithm to determine the equilibrium distribution of the liquid water in the open pore space of gas diffusion layers. The algorithm accounts for the surface free energy based interactions between water clusters in the open pore space. Those interactions occur at the voxel level. Therefore, the collective behavior of the water aggregation and formation of water clusters are expected to behave like a classical statistical ensemble. The energy of each voxel processed by the MC code, is generally depending on the interfacial interaction energies with its neighbours. It is calculated as to catch the natural tendency of the system to reach its minimum energy state, equilibrating the water distribution in the GDL. The algorithm has been applied to sets of tomographic data of GDLs, where both the dry and the wet state of the GDL was investigated. Then, the

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Fig. 3: Equilibrium water distribution (blue) on a 3D GDL structure rendering (red).

Literature: [1] L. Capone, et al., J. Power Sources, to be published. [2] K. Seidenberger, et al., J. Power Sources, 239, 628–641, 2013. [3] D. Landau, et al., A guide to Monte Carlo simulations in statistical physics, 2014. [4] A. Lamibrac, et al., J. Electrochem. Soc., 163, F202-F209, 2016.

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Institute of Computational Physics

1.4

Research Report 2015

Multi-phase modelling of a hydrogen generator

The development of hydrogen generators for direct use with a polymer electrolyte fuel cell (PEFC) is very attractive for applications as decentralized power sources. On-demand production of hydrogen from formic acid can replace the conventional high-pressure hydrogen storage. In this work, we developed and partially validated a computational model of such a device. Contributors:

V. Orava, J. O. Schumacher, P. Cendula

Partners: Funding: Duration:

EPFL, Granit SA, Charles University (CZ), PSI Swisselectric Reasearch, CCEM 2014–2015 the gas and the liquid phase and a constant boiling mixture of formic acid and water. The gas flow rate follows the Arrhenius exponential law and enabled us to extract two parameters - the activation energy 93.6 kJ and the frequency factor 1.24×1010 Hz. In doing so we proceeded by estimating the average temperature of the reactor by iteration between measurements and simulations in the following four steps: First, we derive the parameter values from the measurements using Treact as the average. Second, we perform simulations with the derived values and, consequently, compute the average temperature Tav within the reactor (using Tout as the heating boundary temperature). Third, we use it to derive the corrected parameter values. Finally, we perform a simulation with corrected parameter values and compare the simulated and measured temperature within the reactor Treact and this is shown with experimental data in Fig. 1. We thus conclude that our model is partially validated with the single temperature reading available from the experiments. In addition, the flow pattern in the (transparent) generator qualitatively agrees with the simulation results - rising in the center and sinking close to the perimeter.

Flow Rate HH2+CO2L@L minD

Liquid formic acid (HCOOH) is decomposed into hydrogen and carbon dioxide over a ruthenium catalyst when heat is added. Although the homogeneous catalyst (liquid phase) was sufficiently stable and active for several months at EPFL, traces of water and formic acid in the product gas prevent the direct supply of a PEFC. The heterogeneous catalyst (solid phase) can produce higher quality of the product gas required for PEFCs and thus it is preferred for scaling up from the laboratory tests to the commercial prototypes. A baseline model of the gas and liquid flow, the chemical reaction and heat transfer within the hydrogen generator was achieved in the first project year. Several changes of the catalyst support and generator construction in the second year lead to the first reproducible measurements of the hydrogen generation at EPFL and Granit SA, Fig. 1. The temperature in the generator was measured only at a single point due to technical limitations. 10 8 6 4

Uniform T Simulated Tav

TreactHMeasuredL TreactHSimulatedL

0 75

90 95 100 Temperature @CD

105

110

Fig. 1: Gas flow rate as a function of the temperature. The gas production of a generator with uniform temperature is shown for comparison.

The experiments demonstrate the importance of space abundance between the inner heating tubes and the outer reactor surface, as one of the reactors experienced floating of all catalyst particles on the liquid surface. Hence, the following extensions to the model were incorporated: the motion of the solid catalyst phase, mass transfer between

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Fig. 2: Simulations of the hydrogen generator for inlet temperature 99 ◦ C, catalyst packing 5% vol., pressure 3 bar.

Variation of the generator dimensions and position of the heating tubes (outer and inner) is undergoing in order to find the maximum generator performance at the given working and space constraints.

Zürcher Fachhochschule

Research Report 2015

1.5

Institute of Computational Physics

Electrical losses in hematite during photoelectrolysis

Electrolysis of water using solar energy in a single device would significantly speed up transition to hydrogen energy economy. One approach for construction of such device is the semiconductor-based photoelectrochemical (PEC) cell. Understanding the various recombination losses in the PEC cell through physical model is the starting point for the improvement of its efficiency. Contributors:

P. Cendula, L. Steier, M. T. Mayer and J. Schumacher

Partners: Funding: Duration:

Laboratory of Photonics and Interfaces, EPF Lausanne, Switzerland Swiss Federal Office of Energy 2015â&#x20AC;&#x201C;2017 in the model and the resulting photocurrent j2 is obtained. The area between j2 and j1 therefore presents unambiguously the charges lost by bulk recombination. Finally in (d), also surface recombination term is included in the calculation and the area between j3 and j2 gives solely losses by the surface recombination. The wavelength-dependent performance of hematite and the accompanying losses are compared in the graph of incident photon-to-current efficiency (IPCE) of the PEC cell, Fig. 2. When all absorbed photons would be converted to photocurrent (ideal case), the IPCE of hematite would be equal to the absorptance in hematite layer and reach 50% at 350 nm. In comparison, the measured IPCE and IPCE simulated with the optical model (OM) qualitatively agree and reach 10% at 350 nm, the losses being caused by bulk recombination, slow water oxidation kinetics and small hole diffusion length. We also show that IPCE calculated with the Lambert-Beer law is overestimating the IPCE from the measured data and OM simulations.

Hematite (Fe2 O3 ) is an earth-abundant, stable and non-toxic semiconductor oxide suitable as a photoanode for photoelectrolysis. Its low photocurrent is so far limited by large bulk and surface recombination losses. To quantify these losses, we have coupled our validated optical model of the PEC cell to the drift-diffusion model of the electronic charge transport. Note that during studies of individual electrodes of the PEC cell, an ideal counterelectrode such as platinum is used to focus entirely on the properties of the electrode. For the same reasons electronic currents are reported, and not volume of produced hydrogen.

Fig. 1: Stacked photocurrent-voltage diagram of the electrical losses in the PEC cell with 12 nm of hematite for 1 sun illumination. Potential is reported versus reversible hydrogen electrode (RHE).

In Fig.1, we calculated photocurrent-voltage curves for following scenarios: (a) jmax,OM , perfect conversion of every absorbed photon to photocurrent, (b) j1 without any recombination, (c) j2 with bulk recombination, (d) j3 with bulk and surface recombination. For (a), all absorbed photons are ideally converted to photocurrent without considering any charge separation issues. For (b), only some charges are separated by the electrostatic field, but no recombination (bulk nor surface) at all is included in the calculation. The area between jmax,OM and j1 can thus be described as photocurrent loss due to charge separation. In the (c) case, the bulk recombination term is included

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Fig. 2: Comparison of the measured and calculated IPCE for 1.4 V vs. RHE.

The severe losses quantified in the PEC cell must be individually addressed to reach the 15% solarto-hydrogen efficiency target and combined effort of experiments and theory is necessary.

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Institute of Computational Physics

1.6

Research Report 2015

Development and optimization of patterned porous materials for thermo-neutral fuel cells

The goal of the Swiss Competence Center for Energy Research - Efficient Technologies and Systems for Mobility (SCCER Mobility [1]) is to develop the knowledge and technologies essential for the transition of the current fossil fuel based transportation system to a sustainable one. One step towards to reach these goals is the development of a novel concept of a thermo-neutral fuel cell. This will allow a simplification of the overall fuel cell system and a reduction of the price of fuel cell powered vehicles. Contributors:

J. Dujc, A. Forner-Cuenca, M. Cochet, L. Capone, J. Schumacher, P. Boillat

Partners: Funding: Duration:

Paul Scherrer Institut CTI 2014–2017

The cooling of a thermo-neutral fuel cell is realized by the evaporation of the water that is additionally introduced into the fuel cell and also by the evaporation of the water produced during the fuel cell operation by the oxygen reduction reaction. The presence of liquid water in a PEFC has both positive and negative effects. On the one hand side water is beneficial since, besides the cooling effect, a high water content in the membrane increases the protonic conductivity and thereby the overall fuel cell efficiency. On the other hand the liquid water accumulates in the porous gas diffusion layers (GDL) and thus limits the transport of oxygen. This may lead to a reduction of the fuel cell performance.

Fig. 1: Simulated distribution of the temperature field [◦ C] in an isolated section of a membrane electrode assembly at 0.2 V. The temperature is the highest in the middle where the chemical reactions and the ion transport take place. In the current stage of the model the temperature field is not yet coupled to the two-phase flow. Therefore, there is no in-plane variation of the temperature visible.

The focus of our work in the past year was on the design and analysis of new GDLs, that are capable of better removing water from the electrodes towards the flow field in order to guarantee access for the gases to the electrodes under wet conditions. The new GDL design, which was developed by our partner, the Paul Scherrer Institut, implements a succession of hydrophobic and

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hydrophilic regions [2]. The new GDLs were first characterized experimentally at PSI by measuring the local saturation as a function of the capillary pressure applied. Neutron radiography was used as imaging technique. This allows for the quantification of the water thickness. In a second step, the team at the ICP focused on the numerical modeling and the analysis of the behavior of the new components. We focus on the membrane electrode assembly model which consists of the cathode side GDL and the MPL, the cathode side catalyst layer, the membrane, the anode side CL, and the anode side GDL with MPL, Fig. 1. A special attention was put on modeling of the two-phase flow of water (e.g. [3]) in the porous components of the membrane electrode assembly, Fig. 2. The goal for 2016 is to further develop the existing models and to find the optimal pattern design, which will ensure the best behavior of the fuel cell.

Fig. 2: The liquid water saturation distribution in the hydrophilic treated GDL. The water is accumulated in the hydrophilic regions while the hydrophobic parts of the GDL and the microporous region (below) repel the water.

Literature: [1] http://www.sccer-mobility.ch. [2] A. Forner-Cuenca et al., Advanced Materials, 27, 41, 6317–6322, 2015. [3] J.T. Gostick et al., Journal of Power Sources, 194, 1, 433–444, 2009.

Zürcher Fachhochschule

Research Report 2015

1.7

Institute of Computational Physics

Towards the detailed understanding of coffee brewing

Making excellent coffee is an art. Like cooking, it largely depends on the quality of the used ingredients. However, in addition, how the roasting, grinding and actual brewing processes are performed has crucial impact the resulting coffee as well. This project represents a first step towards the detailed understanding of the flow of hot water through the coffee bed during the brewing process using micro-CT data of ensembles of coffee grains as input for 3D flow simulations. Contributors: Partners: Funding: Duration:

L. Holzer, T. Hocker, O. Stenzel A. Glöss, C. Yeretzian, ZHAW Fachstelle für Analytische und Physikalische Chemie Swiss Food Research 2015

0.5'cm'

Making excellent coffee is an art mastered best pressure during brewing will lead to a specifically by experienced baristas. It requires high-quality tasting coffee beverage. The collective effect of roasted coffee beans, an excellent coffee grinder all of the above mentioned parameters should beand an excellent coffee machine. However, these come apparent in the time-dependent distribution residence times of the water flowing through the are just mandatory prerequisites. In addition, it ofMicro0CT'von'Nespresso0Kapsel'(trocken)' ‘Channeling’'–'Zelluläre'Struktur' is the experience of the barista in how to do the brewing chamber. These residence times can be grinding, filling of the brewing chamber and per- extracted from flow simulations that take the 3D mibed as input, see Fig. 2forming the actual brewing that makes the differ- crostructure of the coffeenumerische'Simula7on'des'Fliessverhaltens:' Micro0CT'von'Nespresso0Kapsel'(trocken)' analysis of dry coﬀee bed ence between an excellent coffee and an average 3. Microstructure 3D0Input'aus'Tomographie' ‘Channeling’'–'Zelluläre'Struktur' 1.4'cm' (NavierJ)Stokes'Gleichung' micro-CT Nespresso dry segmentation fluid and solid phases one. For example, rather large coffee grains will Druckgefälle'"!'Fliessgeschwindigkeit' DarcyJGleichung'!'Permeabilität' lead to short residence times of the water flowing through the brewing chamber. This results in weakly tasting coffee. On the other hand, rather small coffee grains can lead to clogging andMicro0CT'von'Nespresso0Kapsel'(trocken)' chan‘Channeling’'–'Zelluläre'Struktur' large flow channels small flow channels single particles neling effects resulting again in weakly tasting coffee. However, small coffee grains also cause long residence times resulting in bitterly tasting coffee. In any case, knowing the distributions of residence1.4'cm' times of the water flowing through the brewing Fig. 2: RealBsp'Simula7on'des'Fliessverhaltens:' 3D microstructures of a dry coffee bed obtained chamber would represent a detailed fingerprint of from micro-CT data, Geschwindigkeitsfeld' [1]. bed Flow simulations insee dryalso coﬀee the performance of the brewing process and therehigh pressure flow low pressure flow fore could be correlated with the resulting coffee quality. This is exactly the idea behind this preliminary study, see Fig. 1. 4

Was'dominiert'Transport?' Channeling'oder'nicht'

Ca'2.5'cm'

design brewing chamber water flow through coﬀee bed controlling operation conditions p(t), T

Channels'

Zusammenfassung'I:' Mul7skalige'Struktur'

0.3'mm'

coffee beans roasting milling

extraction process  (from fluid element viewpoint)

filling (particle packing) residence times

!1 !2

brewing process water flow trough timedependent microstructure

small channels large channels

sim 3D ul flow at io ns to m 3D o im g rap a g hy in g

"fluid element”

grain characteristics (e.g bimodal PSD)

→ large & small channel flow

5 Fig. 3: Simulations of water flow field through coffee bed for two different external pressures, see also [2].

coffee quality 2 aroma, yield, crema

Fig. 1: Concept of analysing coffee brewing process by performing flow simulations and extracting residence times.

A specific type of roasting and grinding of specific types of coffee beans provides specific coffee grains. Then the filling of a specific type of brewing chamber and the control of temperature and

Zürcher Fachhochschule

→ only large channel flow

Literature: [1] Del Nobile et al., Applications of tomography in food, Industrial Tomography, Ed. M. Wang, Woodhead publishing, 693–712, 2015. [2] M. Petracco, Percolation, Espresso coffee, the science of quality, Eds. A. Illy, R. Viani, Elsevier, 259–289, 2005.

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Institute of Computational Physics

1.8

Research Report 2015

Improved cooling processes for chocolate production

The crystallization of chocolate during the manufacturing process is vital to the characteristics of the final product. We investigated how both advanced computer modelling methods and new inline measurements can be used to optimize crystal formation in chocolate in order to ultimately improve the taste and storage life chocolate products. Contributors:

P. Fahrni, R. Heusser, T. Hocker, Y. Safa

Partners: Funding: Duration:

ZSN, IFNH-ETHZ, Max Felchlin AG and additional industrial partners CTI 2013–2016

Chocolate is usually characterized using laboratory equipment under ideal conditions, and often it is not clear how closely these conditions mimic the real production process. Therefore, our approach to making better chocolate has both an experimental and a theoretical element. On the one hand, we use sophisticated inline measurements to monitor the crystallization behavior of chocolate under real production conditions and, on the other hand, we use these data to validate our computer models, which then can be used to explore different optimization scenarios [1]. An overview of the employed methods is given in Fig. 1. Overview modelling activities spatial heat conduction models

sensor testing models

cooling at -1 ºC/min with 0.1 % seeds

V s2 fractionsαs1==β0, m= final final fractions = β=VI0,=u =0 0,%, m100 = 100 %

0.00

model fit

-0.05

temperatures, heat-fluxes, humidity, US-detachment

sensor platforms for inline tests

initial 1.5 composition

DSC data

-0.10 -0.15 -0.20

model fit

DSC data

1.0 0.5

-0.25 0.0

understand raw materials,

get cryst. kinetics

predict cryst. formation in cooling tunnels

VI cryst βstable1

V cryst βstable2

20 T (ºC)

αunstable cryst

model prediction

spatial crystallization models

Commercial products used by chocolate makers for inline measurements did not meet our requirements, so we had to develop our own hardware.

20 T (ºC) V cryst βstable2

αunstable cryst

total total

1.5

m→α m → βV

-0.10

m → βVI

-0.15 -0.20

βV → m

1.0

0.5

α→m βVI → m

-0.25

0.0

-0.30

Thomas1: Hocker, ZHAW 2 September 22, 2015 Fig. Overview of ICP’s modeling and inline measurement Differential Scanning Calorimetry for activities all Requirements within the Coolcon research project.

VI cryst βstable1

total total

0.00 -0.05

homogeneous crystallization models

Jdsc (W /g)

Lab tests

re-heating at 4 ºC/min

fractionsαs1==14 3, s2 = 83, 14,%, m =β 0VI = 3 % finalfinal fractions %, βV u==83

Jdsc (W /g)

DSC 1 STARe System Innovative Technology Versatile Modularity Swiss Quality

optimize mould and cooling tunnel parameters

Jdsc (W /g)

optimal sensor placement

Jdsc (W /g)

Thermal Analysis Excellence

Production tests

temperatures, humidities and heat fluxes while the chocolate moulds travel through the cooling tunnel. Despite its small size, this logger has an unmatched performance, containing 14 channels and being able to store data for up to 8 hours. Concerning the modeling of the actual chocolate solidification under production conditions, we established a link to differential scanning calorimetry (DSC) data to assess the crystallization and melting behavior under idealized lab conditions. A typical example of the model-based analysis of DSCdata of seeded cocoa butter, provided by L. Rejman ofhom. IFNH-ETHZ, is cocoa shown in Fig. 3. Fitting cryst. model to butter DSC-data

20 T (ºC)

α → βV 10

βV → βVI 20 T (ºC)

October 13, 2015

Fig. 3: Fitting extended Révérend crystallization model [2] to seeded cocoa butter DSC data and predicting the DSCcontributions of the various phase transformations.

This 0D cystalization model serves as input for the more sophisticated cyrstalization model developed by Y. Safa. Safa’s model takes into account the spatial dependencies and nonhomogeneous thermal boundary conditions present under production conditions, see additional contribution by Y. Safa within this report.

Fig. 2: Xocolog data logger developed by P. Fahrni to perform inline temperature, heat-flux and humidity measurements.

As an example shown in Fig. 2, we developed our own data logger the size of an iPhone to record

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Literature: [1] T. Hocker, Perfecting the chocolate making process, International Innovation, 2015. [2] B.J.D. Le Révérend, I. Smart, P.J. Fryer, S. Bakalis, Modelling the rapid cooling and casting of chocolate to predict phase behaviour, Chemical Engineering Science, 66, 1077–1086, 2011.

Zürcher Fachhochschule

Research Report 2015

1.9

Institute of Computational Physics

Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects

Oxide scale formation on metallic interconnects contributes to the overall degradation of solid oxide fuel cell (SOFC) stacks. On the anode side, thermally grown oxide scale might contain additional nickel, nickel oxide, or nickel chromium spinel phases – depending on the stack composition and the applied operation conditions. We investigated the influence of Ni on the electrical conductivity of oxide scales since this can provide new strategies to significantly decrease the ohmic losses associated with anodic oxide scale formation. Contributors:

M. Linder, T. Hocker, L. Holzer, O. Pecho

Partners: Funding: Duration:

IMPE, DLR-Stuttgart, FH-Esslingen, Hexis AG Swiss Federal Office of Energy, Swiss Electric Research 2012–2015

Oxide scale formation on the anodic side of metallic interconnects (MICs) leads to complex microstructures and involve a multitude of different SEM image REM121797 chemical species, see Fig. 1. resin

NiO

3Ni2+

Ni-mesh

Cr2O3

NiO

Cr2O3

NiO

Cr2O3

ii)

internal oxidation zone CFY Cr2N

200 µm

interconnect

Ni 20 µm

NiO formation

electrical conductivity

eff

NiO

spinel formation

NiCr2O4 spinel

NiCr2O4 20 µm

spinel decomposition

Cr2O3 matrix

NiO

2Cr3+

gas gap/NiCr2O4 spinel formation zone 3Ni2+ + 4Cr2O3(g) = 3NiCr2O4 + 2Cr3+

Cr2O3

NiCr2O4/NiO spinel formation zone 2Cr3+ + 4NiO = NiCr2O4 + 3Ni2+

Ni(OH)2(g)

VO VO VNi Ni(s) Cr2O3

Ni-O-OHads

Cr2O3 NiCr2O4 spinel

Cr2O3

NiCr2O4

H2O

O2(g)

In a series of experiments using pellets made of chromium oxide (Cr2 O3 ) mixed with different amounts of Ni-particle the electrical conductivity of Electrical conductivity variation based on specific microstructure changes during such ensembles has been investigated, see Fig. 2. heat exposure under different atmospheres in Nickel containing Cr O layers Ni

Fig. 1: Cross section of a MIC operated in a Hexis SOFC stack at 900 ◦ C running on CPOx reformed natural gas for 40000 h including 15 redox cycles [1].

Cr2O3 matrix

NiO

Anode Ni-mesh flow channel Cr2O3 + int. oxi. zone CFY

Cr2O3 Ni

pore

gas gap

remaining anode layer

and spatial arrangement, i. e., on their microstructures. This is explained in more detail in Fig. 3, where changes in the main electrical current pathways are associated with microstructural and compositional changes.

Cr2O3

Cr2O3 pores Ni NiO NiCr2O4 spinel main electric current pathway Ostwald ripening

Cr2O3 matrix

Fig. 3: Microstructure changes during the evolution of the Ni containing Cr2 O3 pellets under reducing, oxidizing and re-reducing conditions and corresponding changes in main electrical current pathways.

Ostwald rippening dispersed Ni

Ni Ni 20 µm

It turns out that overall electrical conductivity varies by several orders of magnitude and depends on both the extrinsic electrical conductivities of the present phases as well as on their sizes, shapes

Literature: [1] M. Linder, T. Hocker, L. Holzer, O. Pecho, K. ,A. Friedrich, T. Morawietz, R. Hiesgen, R. Kontic, B. Iwanschitz, A. Mai, J. ,A. Schuler, Solid State Ionics, 283, 38–51, 2015.

reducing atmosphere

oxidizing atmosphere

reducing atmosphere

eff

Fig. 2: Electrical conductivity variation based on specific microstructure changes during heat exposure under different atmospheres in Nickel containing Cr2 O3 layers.

It turns out that redox-cycles and the according transformations between pure Ni and Nicontaining oxides play a crucial role in the observed electrical conductivity changes. This provides explanations for the often observed strong effect of redox-cycles on the degradation behavior of SOFC-stacks.

time

Zürcher Fachhochschule

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Institute of Computational Physics

1.10

Research Report 2015

New generation of high-performance air heaters

The controlled heating of air flows plays a big role in a number of industrial processes. Leister Technologies AG, Kaegiswil, is the world leader in plastic welding and process air equipment that relies on the efficient and reliable supply of heated air. In collaboration with D. Penner’s team at IMPE and G. Boiger’s team at ICP, this project explores new manufacturing and design routes to develop a new generation of high-performance air heaters for application in future Leister products. Contributors: Partners: Funding: Duration:

T. Hocker G. Boiger, D. Penner (IMPE), Leister Technologies AG CTI 2015–2017

Recent advances in the development of new materials and manufacturing methods with potential applications to air heaters provide a large potential for improving the heater performance at reduced manufacturing costs. However, while the choice of potential materials and designs is large, optimizing derived products purely by trial and error would be an almost impossible task due to the large number of selectable parameters. Instead, it is much more efficient to develop computer models that provide a basic understanding of the physical phenomena taking place and allow one to run extensive parameter studies. As an example, a electro-thermo-fluidic model has been implemented in our in-house FE-tool Seses. It approximated an air heater with electrically conducting walls, made e. g. from silicon carbide. The model takes into account the flow of electrical current through the walls which, depending on the design of the electrical contacts, might be rather inhomogeneous.

Fig. 2 shows typical temperature (left) and current density (right) distributions within such an air heater. Brighter colors indicate higher values of both temperature and current density. temperatures

electrical current densities

Fig. 2: Typical temperature and current density distributions in an air heater with heated walls.

Since the electrical contacts have been assumed to lie at the border, this creates an inhomogeneous distribution of the electrical current and hence a inhomogeneous temperature distribution. Fig. 3 compares the air outlet temperatures of different heater designs with each other for different heating powers. As expected, the air outlet temperatures increases almost linearly with heating power indicating that in theses cases the heat losses to the surroundings are small. However, the outlet temperatures vary quite significantly between the different designs and are significantly lower that the theoretical maximum outlet temperature for a given heating power. comparison of outlet temperatures 900 225 225 800 81 theoretical 81 700

max. temp

Fig. 1: Fully parameterized geometry of air heater model implemented in our in-house multi-physics FE-codeSeses.

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70 40 70 40

mm mm mm mm

600 T (C)

The model then calculates the corresponding Joule’s heat and how it is transferred to both the air and the surroundings through heat losses. Fig. 1 shows typical geometries of such a model. The geometry has been fully parameterized in order to efficiently investigate a large variety of different designs.

cha cha cha cha

500 400 300 200 100 0 0

500

1000 1500 Pel (W)

2000

2500

Fig. 3: Air outlet temperatures versus heating power for different air heater designs.

Zürcher Fachhochschule

Research Report 2015

1.11

Institute of Computational Physics

Numerical Simulation of Stacked OLEDs and Solar Cells

In this project we investigate charge transport across organic-organic interfaces in organic semiconductor devices such as OLEDs and solar cells. In the framework of a 1D driftdiffusion model a prototype interface model for stacked devices is implemented and analyzed. Contributors:

E. Knapp, B. Ruhstaller

Partners: Funding: Duration:

SNSF 2014â&#x20AC;&#x201C;2016

OLEDs consist of multiple layers of organic semiconductor materials deposited on top of each other. The use of different layers allows to balance charge transport and optimize optical properties which thus leads to an improved device performance. Taking this concept one step further leads to tandem devices where multiple electroluminescent (OLED) units are vertically stacked and connected by a interconnector layer, which serves as a charge generation layer. Such tandem devices show an enhanced light emission as multiple photons can be emitted for each injected electronhole pair thanks to the charge generation layer, see Fig. 1.

voltage characteristics as the tandem device with the interface model (green circles). This prototype interface is an important step towards reaching the long-term goal of simulating tandem devices and will also allow the study of tandem solar cells in which multiple units with different light absorption properties are stacked.

Fig. 1: A single unit OLED is shown on the left whereas on the right side two units are stacked leading to a tandem device which has a higher current efficiency and luminance.

The enhanced current efficiency and luminance at low current densities and enhanced lifetime for tandem devices makes them very attractive for applications. In this project a thermodynamic hopping model as proposed by S. Altazin (Fluxim AG) is translated to an interface condition within the 1D drift-diffusion framework. With this prototype we are able to analyze different interface configurations depending on the energy level of the HOMO and LUMO of the individual layers. In Fig. 2 we compare the simulation of a single unit (blue) with a tandem device (green circles) as illustrated in the legend above the graph. Two single units in series are drawn in black and show the same current-

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Fig. 2: The current-voltage curve of a single OLED unit is shown as the blue dotted line. The tandem device is once modelled as two single units in series (black line) and with the interface model as the entire cell.

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Institute of Computational Physics

1.12

Research Report 2015

LED-based sun simulator for solar cell characterization

Artificial light sources, which are used for performance characterization of photovoltaic cells, should spectrally, spatially and temporally match the natural sunlight as close as possible for reliable measurements. We have designed and built a sun simulator based on high-power LEDs, which can be matched to the sun spectrum in the range of 400–750 nm within the spectral A+ class and is compact enough to be integrated into the commercial solar-cell characterization system of our industrial partner. Contributors: Partners: Funding: Duration:

M. Jazbinsek, M. Krajewski, K. Pernstich, B. Ruhstaller Fluxim AG KTI 2013–2015

Recent advances in high-power light-emitting diode (LED) technology have enabled the use of LEDs for solar simulators with many advantages over traditional xenon and metal halide lamps, such as long lifetime, much lower price, flexibility to match and fine-tune a desired spectrum and modulate it in real time, and LEDs are additionally more environmentally friendly. Within the CTI project PAIOS+ we are developing a sun simulator implementing 16 LEDs to match the sun spectrum or another desired spectrum, as close as possible. The electronics is designed in a way that each of the LEDs can be driven individually. The software control of the electronics will also enable real-time monitoring and fine adjustment of the spectrum. Our home-built sun simulator is very compact, with a footprint of the 16 LEDs of less than 2 cm2 , to be later on easily integrated in photovoltaicmeasurement set-ups.

Fig. 1 shows a possible spectrum of the first version of our simulator, using various-color LEDs ranging from 440 nm to 730 nm peak wavelength. The wavelength range can be straightforwardly extended using compact LEDs emitting deeper in ultraviolet and further in the infrared range. For reliable solar cell characterization, light coming from different LEDs should be homogeneously distributed at the place of the sample, so that both light intensity and its spectral distribution are uniform across the sample. To achieve a high homogeneity we implemented special light-mixing optical elements that homogenize the initially nonuniform LED sources; a detail is shown in Fig. 2.

Fig. 2: Detail of the spatial mixing of different-color LEDs (shown for 3 out of 16 LEDs), which is achieved using special light-mixing optics (ZEMAX simulation).

Fig. 1: Sun spectrum (AM1.5g) and a calculated sun simulator spectrum from our multi-LED solar simulator.

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Our future work will concentrate on the optimization of the software control, complete optical characterization of the sun simulator under working conditions and extension of the emmiting wavelength range.

Zürcher Fachhochschule

Research Report 2015

1.13

Institute of Computational Physics

Impact of sand content on solute diffusion in Opalinus Clay

L. Keller

Partners: Funding: Duration:

Nagra 2015â&#x20AC;&#x201C;2016

Low-permeability clay rock formations are considered as potential hosts for radioactive waste. Clay rocks typically have a very low hydraulic conductivity and the transfer of radionuclides will be largely controlled by diffusion. Diffusion depends strongly on geometric parameters, which in turn are intimately related to the microstructure. The mesostructure (micro to millimeter scale) of clay rocks was considered as two-component mixture consisting of impermeable non-clayey sand grains embedded in a permeable clay matrix. Provided that representative diffusion properties can be defined, the clay matrix can be treated as a continuum. Under these conditions diffusion at larger scales will depend on geometric properties of the mesostructure. The objective of this study, then, is to analyze geometric parameters, which control

diffusion at larger scales. In a first step a set of different clay matrix mesostructures were reconstructed on the base of synchotron X-ray computed microtomography applied to clay rock samples from northern Switzerland, e.g. Opalinus Clay see Fig. 1. In a second step mesostructural effects on diffusion were quantified by applying diffusion simulations to reconstructed mesostructures. Further analysis revealed that contrictivity is the most dominant parameter, which controls diffusion on the millimeter scale in Opalinus Clay. Regarding diffusion, the mesostructure of the clay matrix is near isotropic. Hence, the reason for anisotropic diffusion in Opalinus Clay must be searched on the nanometer to micrometer scale and there is caused by anisotropic pore path tortuosity related to shape preferred orientation of clay platelets.

Fig. 1: a) Reconstructed microstructures of clay matrix (rows) of the analyzed sample (columns). XCT refers to the analyzed volume. b) Diffusion simulations: the colors represent normalized concentrations within the clay matrix in case diffusion occurs in x-direction. The calculations yielded the ratio De /Dm , where De is the effective bulk diffusion coefficient and Dm is the isotropic bulk diffusion coefficient of the clay matrix in absence of a non-clay material. According to the theory of diffusion in porous media, the relation between De and Dm may be given by De =f GDm , where f is the clay matrix content and G is the geometric factor that accounts for microstructural effects on diffusion. c) Geometric factor versus clay matrix content. Black squares were determined on the base of diffusion modelling and the black line is a fit to these data.

ZĂźrcher Fachhochschule

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Institute of Computational Physics

1.14

Research Report 2015

Fast transient simulation of semiconductor devices

An implicit adaptive solver was developed at the ICP, which allows for the fast simulation of time-dependent charge transport in semiconductor devices. This solver is about 150 times faster than a previously used explicit solver. It has been partially incorporated in the latest version 4.3 of the OLED and organic solar cell simulation software Setfos by Fluxim AG. Contributors:

C. Kirsch, S. Altazin, A. Stous, B. Ruhstaller

Partners: Funding: Duration:

Fluxim AG CTI 2013–2015

computation time accuracy

The transient response of semiconductor devices to various changes from equilibrium is required for several characterization techniques, such as photo-CELIV, transient photovoltage, transient photocurrent, transient electroluminescence, and dark injection transient measurements. Measurement data can be used to estimate mathematical model parameters. For a typical parameter estimation based on curve fitting multiple numerical simulations of the transient response need to be carried out. Therefore, efficient parameter estimation requires fast device simulations. Due to their conditional stability the explicit transient solvers available in previous Setfos versions converged only for relatively small time steps. A large number of time steps was thus necessary for these solvers to reach the prescribed simulation end time, which led to a long computation time. This disadvantage of conditionally stable solvers is illustrated in Fig. 1.

stable unstable

range of time step sizes unavailable to explicit solvers

designed to be unconditionally stable, such that the full range of time step sizes may be used in the simulation with no risk of non-physical solutions. For these solvers, the time step size is limited by the accuracy condition only, and thus the computation time for the simulation may be much shorter. An implicit transient solver was developed at the ICP within this CTI project. It has been implemented by Fluxim software engineers and is available in the latest Setfos version 4.3. During the numerical simulation of transient phenomena the relationship between accuracy and time step size (blue line in Fig. 1) often changes over time. Abrupt changes from equilibrium, for example, may require very small time steps in order to resolve the transient response of the device. On the other hand, much larger time steps may be used when the device is close to equilibrium. A variable time step size is commonly employed to ensure that the accuracy criterion is satisfied at all times while the computation time is minimized.

prescribed minimum accuracy time step size

Fig. 1: The stability condition for explicit transient solvers may severely limit the time step size used in simulations.

The blue line shows how both the accuracy and the computation time increase with decreasing time step size. For a prescribed minimum accuracy (black dashed line) a certain time step size must not be exceeded. However, the stability criterion for explicit transient solvers often imposes a more severe restriction: it requires the time step size to be located inside the stable region, otherwise nonphysical behavior of the numerical solution, such as oscillatory exponential growth, may occur. On the other hand, implicit transient solvers can be

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Fig. 2: The time step size as chosen by the adaptive timestepping scheme, vs. time, for explicit and implicit solvers. The inset figure shows a zoom of the region around 10−5 s.

The time step size vs. time is shown in Fig. 2 for a test problem in which the applied voltage changes abruptly initially and again after 10−5 s. The adaptive time-stepping scheme varies the time step size accordingly over several orders of magnitude. For the explicit solver it is limited to about 2 × 10−11 s because of the stability condition, whereas the unconditionally stable implicit solver may use much larger time steps. In this test the implicit solver was about 150 times faster than the explicit solver.

Zürcher Fachhochschule

Research Report 2015

1.15

Institute of Computational Physics

CARDYN - Charge carrier dynamics in organic electronic devices

The correct description of charge carrier transport is crucial in the understanding of the physics of organic electronic devices such as organic light-emitting diodes (OLEDs) and organic solar cells (OSC). This project aims to improve existing models and develop new ones to describe the experimental data. SNF and DFG give joint funding for two PhD projects. Contributors:

S. Züfle, E. Knapp, M. Regnat, B. Ruhstaller

Partners: Funding: Duration:

Universität Augsburg SNF, DFG 2015–2017

The electric current in organic electronic devices can be modeled with a drift-diffusion approach. Several physical processes have to be taken into account, like charge carrier injection and extraction, transport in disordered materials, charge carrier recombination and trapping. In order to find material parameters often monopolar devices are fabricated, where the material to investigate is sandwiched between two contacts. Choosing appropriate contact barriers ensures that only one charge carrier can flow through the device. The measured IV-curves can then be used to extract the charge carrier mobility of this material, by fitting a space-charge limited current model. In complete OLEDs or organic solar cells more layers are needed, in order to guide the charge fluxes. In OLEDs it is important to have a low injection barrier, which can be achieved by injection layers. Most of the materials employed as electron transport layers are polar, they exhibit a sheet charge density at the layer interfaces. This charge affects the built-in field of the electrodes and leads to an enhanced hole injection. One way to measure these injected holes is impedance spectroscopy, which is sensitive to the mobile charges in the device. In this case two plateaus in the capacitance are observed in the different operating ranges. As injection is always a strongly temperature-dependent process, a temperature variation leads to a shift of the transition frequency between the two plateaus. From an Arrhenius analysis of the transition frequency the ac-

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tivation energy can be extracted. In this project also novel hole injection materials are investigated, such as HATCN. Due to the position of the energy levels the injection mechanism is fundamentally different from other injection materials. For this purpose a new interface model (Altazin-Model) is being developed with the associated industrial partner Fluxim AG. It will be able to describe the hole injection from HATCN, but will also be of interest for interface layers in tandem devices. With appropriate charge transport models and efficient numerical solvers we will be able to extract crucial device parameters such as charge injection parameters from a comparison of measured and simulated data. Thus, we pave the way to a noninvasive in-situ method for studying charge transport in OLEDs and solar cells.

Fig. 1: Capacitance-frequency plot at varied temperatures (C-f-T). The shift of the transition frequency shows Arrhenius activation.

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Institute of Computational Physics

1.16

Research Report 2015

Fluxim Research and Development Support

Not all the software the ICP creates during its R&D projects with Fluxim AG is easy to deploy after its successful completion. Fluxim as a spin-off and partner of the ICP helps to conserve the gained knowledge for the ICP and third parties and engages some ICP staff to assist in doing so. Contributors:

K. Lapagna, S. Züfle, B. Ruhstaller

Partners: Funding: Duration:

Fluxim AG 2014–

As an ICP spin-off, Fluxim is still closely collaborating with topic related groups of our institute. Big parts of this collaboration are based on synergy effects, where the ICP and Fluxim are contributing to the same projects and are working towards the same goals. The offices of Fluxim and the ICP are closeby which gives the employees the freedom and flexibility to easily roam between the two sites and work side by side with their partners if the situation calls for it. This leads to a more efficient exchange of information, quicker decision making and a more specific shared vision on how to advance a common project. Most projects will produce a lot of new ideas, refined physical models and bits and pieces of software, that were used to create and gather the results that were necessary for the goals of these ventures. Unfortunately, most of the resulting software is highly adapted to the use case that was needed for a specific task, to answer a specific scientific question. It is often not usable for third parties or covers just parts of the full power of the underlying models. Fluxim, as a company that operates in the private sector, has a strategic interest in making knowledge, that was gathered during these projects, available to third party companies and other research units, outside the scope of the projects where the ICP directly participates. Thus, there is extra effort needed to polish, port and integrate the newly acquired knowledge and software pieces into the products of Fluxim. If ICP staff is involved in walking this extra mile, this effort is commissioned through the Fluxim Research

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and Development Support project. This includes tasks like making the software more stable, more flexible, faster and most of all, more user friendly and accessible. As an outcome, a lot of reusable software is made available in a more powerful and convenient way. The ICP immediately profits from this, as it can make use of this software in consecutive R&D projects, letting Fluxim take care of the maintenance and fully concentrate on the new tasks at hand. With a symbiosis like this, less of the gained knowledge gets forgotten over time or stays inaccessible in unmaintained private software archives. Recent examples of this R&D collaboration are the successful integration of Mie particle scattering, simulation of microtexture scattering topography data and the integration of simulations based on ray-tracing into Setfos. In addition there is a lot of fine tuning, bug fixing and new sets of results and plots that are made available with the help of this joint effort.

Fig. 1: Visualization of a randomly generated microtexture.

Zürcher Fachhochschule

Research Report 2015

1.17

Institute of Computational Physics

Electrical interconnections in solar cells and modules

Thin film solar cells and modules rely on transparent conductive oxides (TCO) to transport the generated current to external contacts. Since a few years a metallic mesh is used in combination with the TCO to improve the conductivity. At ICP numerical simulations are used to optimize the current collection by minimizing both electrical losses and optical losses due to absorption and shadowing in the TCO and mesh. Additionally, the size of the interconnected cells in large area modules is optimized to minimize the overall losses. Contributors: Partners: Funding: Duration:

P. Losio, B. Ruhstaller CSEM, EMPA, PV Lab-EPFL, LPI-EPFL Swiss Federal Office for Energy, CCEM 2014–2017

Thin film photovoltaic modules can be manufactured on large areas and laboratory results indicate the possibility to obtain a good efficiency at limited costs, however one of the main limitations in transferring high performance laboratory solar cell to large area is related to electrical losses over the large surfaces necessary for commercial devices. Transparent conductive oxide (TCO) layers are usually used to transport the generated current, however the layer conductivity is usually orders of magnitude lower than in metals thus leading to ohmic losses. The conductivity of TCO layers can be increased during manufacturing leading usually to a loss of efficiency because part of the light is absorbed in the TCO layer. In recent times, a fine metallic conductive mesh is added on top of the TCO surface to improve the conductivity at the expense of a localized total loss of generated current due to shadowing. 12 Loss < 10% Loss < 8% Loss < 6% Best cell width Best result, loss 5.6%

cell width [mm]

10 8

tion of the trade-off between electrical losses and light absorption losses. At ICP simulations are done to optimize large area modules considering all these aspects. An example based on a CIGS cell is shown in Fig. 1, a wide range of TCO thicknesses and cell widths were considered: the minimal achievable loss is 5.6%. The usable parameter space for TCO thickness and segment width defining loss thresholds of 6%, 8% and 10% is shown in Fig. 1. The optimization of metallic meshes in combination with TCO layers requires the use of a computationally efficient 2D+1D FEM approach to correctly model the voltage distribution across the cell and the electrical losses as shown in Fig. 2. In the example the external contact is on the left edge; due to a poor conductivity of the TCO layer the voltage is not uniform across the device. Ohmic losses indicated by the color scale are larger near the contacting electrodes due to a larger current density. The FEM approach allows to optimize the TCO thickness and the shape of the metallic mesh.

6 4 2 0 0

200

400 600 TCO thickness [nm]

800

1000

Fig. 1: Parameter space for three power loss thresholds in CIGS solar modules. The parameters necessary for achieving the lowest losses are marked by the red dot. The best cell width as a function of TCO thickness is marked by a green line.

Scaling solar cells to large area modules additionally requires to take into account the losses of active area necessary to accommodate the serial interconnection of solar cells and a careful optimiza-

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Fig. 2: Voltage distribution and ohmic losses on the top electrode of a 0.5 cm2 organic solar cell using a front TCO and a metallic mesh, the external contact is at the left edge. The colorbar indicates the relative ohmic losses; the operating voltage is 0.64 V. The metallic contact shape is shown at the bottom.

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Institute of Computational Physics

1.18

Research Report 2015

Rigorous simulation of light scattering

Light scattering plays an important role in the optimization of high performance solar cells, especially for hybrid tandem cells combining different solar cell technologies like perovskite solar cells, heterojunction Silicon solar cells and CIGS solar cells. Usually solar cells have a rough surface and often the typical size of structures on the surface is comparable with the light wavelength thus requiring a rigorous simulation to obtain reliable results. A combination of rigorous simulations and approximations allows to reduce the time necessary to complete a simulation. Contributors:

P. Losio, B. Ruhstaller

Partners: Funding: Duration:

CSEM, EMPA, PV Lab-EPFL, LPI-EPFL SNF 2015–2019

Light scattering plays an important role in the optimization of high performance solar cells: optimized light scattering allows to reduce the amount of material needed and to improve the conversion efficiency of solar cells. A current topic of research to achieve solar modules having 25-30% conversion efficiency are hybrid tandem solar cells combining different solar cell technologies: usually a perovskite solar cell combined with either a heterojunction Silicon solar cell or a CIGS thin film solar cell.

As an example, the intensity of scattered light above a rough Zinc oxide (ZnO) surface is shown in Fig. 1, the numerical solution was computed using the commercial software package JCMsuite. Hybrid solar cells have however a total thickness of ≈ 300µm which is about two orders of magnitude larger than the rough surface features under consideration. A rigorous computation of the whole cell structure is computationally very expensive. An approach to reduce the total computation time is being developed at ICP: the computation is split into a rigorous near field computation near the rough surfaces and a more efficient ray-based method for thick, homogeneous layers.

Fig. 1: Representation of the scattered light intensity above a rough ZnO surface, λ = 600nm, side length 4.5µm.

Fig. 2: Propagating modes scattered by a rough ZnO surface texture represented as vectors.

These three types of solar cells usually have a rough surface and the typical size of structures on the surface is comparable with the light wavelength. A reliable simulation of this situation requires a rigorous approach based on numerically solving Maxwell’s equations using the finite elements method (FEM).

To this purpose the propagating modes are extracted from the FEM near field solution and can be used with other simulation tools as shown in Fig. 2. All incidence angles from both sides of the rough interface are considered to compute the complete Bidirectional Scattering Distribution Function (BSDF) matrix entries.

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Zürcher Fachhochschule

Research Report 2015

1.19

Institute of Computational Physics

Simulation of heat transfer processes within a fuel cell system based on OpenFoam

A versatile, fully modifiable, finite volume, thermo-fluid-dynamic model of a SOFC system, has been created based on OpenFoam. This flow- and heat transfer model takes the level of physical detail beyond that of previously known simulation methods. Contributors:

G. Boiger, J. Fuchs, C. Meier, V. Lam

Partners: Funding: Duration:

Hexis AG Hexis AG 2014â&#x20AC;&#x201C;2015

The model can support the limited temperature measurement options inside a stack and will help to gain a more detailed insight into overall thermal conditions. Thus high temperature gradients within the SOFC stack can be averted more efficiently in future system designs. This work focuses on the modeling of two major thermal aspects with impact on the temperature distribution of a SOFC system: anisotropic heat conduction within a stack and thermal radiation effects. Because of the layer structure of the SOFC stack, heat conduction properties, orthogonal to these layers vary from those in radial direction. In our model, the implementation of layered stack geometry is based on one continuous, porous domain. In order to realize anisotropic heat conduction mechanism in this domain, the concept of thermal baffles is used. According to OpenFoam, a thermal baffle has zero physical thickness in the flow domain, but non-zero thickness for thermal calculations. Representing the different layers in the actual structure, thermal baffles are introduced into the stack domain and act as a quasi-anisotropic axial thermal resistance. A model for considering relevant thermal radiation effects has been devised as well. The radiation calculation implementation in OpenFOAM [1] and Ansys CFX [2] focuses on the fluid domain, separating interacting solids. This makes sense for most applications, where every solid domain has an interface with the fluid domain. In our case though, the stack domain is represented as porous solid, located within the fluid domain without defined stack-fluid interface. Energy coupling between the two phases is realized by vol-

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umetric heat sources. Thus common, interface based methods of implementing thermal radiation between solid objects will not work. The problem has been overcome by modifying the solver, such that an additional fluid domain, connecting the stack to the interacting solid domains, could be introduced.

Fig. 1: Side view of simulation results of the thermo-fluiddynamic model of a SOFC system.

Literature: [1] http://OpenFOAM.org. [2] Ansys CFX Solver Modeling Guide, 2013.

www.zhaw.ch

Institute of Computational Physics

1.20

Research Report 2015

Tentative modelling of the failure in Solid Oxide Fuel Cell

The thermo-mechanical failure of the interconnect components in Solid Oxide Fuel Cell SOFC is investigated based on efficient numerical models and in the light of the operational observations. Varied methods based on continuum and discontinuum approaches are examined, in the former the damage model is considered with both local and non-local formulations. In the later, the fracture mechanics is analyzed with the application of both XFEM and cohesive element methods. The developed approach present an advanced predictive tool to be exploited in a reliable design of SOFC stack. Contributors:

Y. Safa, T. Hocker

Partners: Funding: Duration:

Hexis AG, NM Numerical Modelling GmbH Swiss Federal Office of Energy 2015â&#x20AC;&#x201C;2017

Solid Oxide Fuel Cell SOFC system developed by Hexis AG, Winterthur-Switzerland presents a promising heat and power source based on the chemical energy of natural gas. Operated at high temperature, the interconnect components of SOFC, exhibit some damage. Therefor, the control of the thermo-mechanical failure in the interconnect parts is highly required for the structural integrity of the designed system, and hence, its long service life. Although that operated system may survive the onset of some stable cracks in the cell, the unstable crack propagation lead to fuel leakage and power losses. Hence, the identification of the typical failure modes from the fractography observations of the failed cells present an initial investigation step, like for instance, observation of propagated cracks in radial and tangential direction in the coating layers on anode and cathode sides in postmortem cells. Later, the analysis of fracture mechanics of the components would be a highly relevant topic in a complementary needed step for a reliable design guideline of the stack. The goal of this work is to provide a numerical predictive tool of the fracture toughness, crack propagation and damage evolution in the cells in order to develop a primary failure criteria. This is to serve in the structural design of the stack, the material selection and the optimization against thermomechanical failure of the interconnect parts. A continuum approach based on the damage evolution is used to represent the crack where material defects are initially considered with a random values of the damage energy threshold, Fig. 1a. To avoid inconsistent localization of damaged zone, a non-local damage formulation is used to represent a realistic damage propagation, Fig. 1b. Since the damage model doesnâ&#x20AC;&#x2122;t represent the interaction of the crack faces (contact and friction), a discontinuous approach is used with the application of XFEM

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eXtended Finite Element Method, Fig. 1c. This to represent stress singularity at the crack tip as well as the discontinuous displacement on the crack boundary. A numerical estimation of stress intensity factor is obtained with different methods, like for example, the application of J-integral. However, due to limited-implementation capability of XFEM to capture the crack branching and fragmentation, cohesive-zone model is applied. This allows to avoid singular and rather unphysical behavior of the stress on the crack tip. Finally, a realistic perspective of this work is to achieve an interaction between a local micro scale simulation in local parts and the macro scale analysis of the stress in the global domain obtained by SESES Finite Element Code.

Fig. 1: Failure models in a quarter part of electrode. Figs. (a), (b) and (d) are the results of the simulation using AKANTU package, Fig. (c) is obtained using the GETFEM package.

ZĂźrcher Fachhochschule

Research Report 2015

1.21

Institute of Computational Physics

A model-based optimization of cooling tunnel processes

A model describing the crystallization of a melt sample exposed to the wind flow in a cooling tunnel has been implemented. The effects of the heat transfer and the interconversion between melt phase and crystal polymorphism were analyzed. A new enthalpy-formulated coupling between the phase kinetics and the Stefan problem was introduced. The flow characteristics and the heat transfer mechanisms along the circumference of the cylindrical sample were considered with separate contributions on the front and rear parts of the sample and turn to have a clear influence on the cocoa butter crystal distribution. The numerical results for the temperature distribution within the sample are in agreement with measurements. Contributors:

Y. Safa, T. Hocker

Partners: Funding: Duration:

IFNH-ETHZ and several industrial partners CTI 2013â&#x20AC;&#x201C;2016

The matured know-how of the thermal processing of the manufactured solids from its melt is one of the key issues for the high quality-control in the production line of these materials. Beside the cooling rate and the distributed heat flux, the solidification process can be influenced by kinetic effects and then, several polymorph constitutions arise in the processed sample. This is due to the mass diffusion between adjacent phases, the metastable forms that can exist or coexist in the presence of more stable forms. However, the quality of the product and the endurance of its desired properties that are designed for some specific applications can be affected by the crystal behaviour, like for instance, the instability of certain crystals, the interconversion between crystal phases and the transition between crystals and melt phase. Since material processing undergoes often a thermal history, like cooling from a high temperature, that should be managed through either the optimized mould geometry or the controlled cooling tunnel parameters. A computational model describing energy transfer coupled with mass transformation between crystal phases in chocolate was developed at ICP in a collaborative research work with IFNH-ETHZ and some other industrial partners. This model allows one to predict the temperature and the crystal evolutions, see Fig. 1-2 and the corresponding changes in the properties through processes like cold moulding, tempering and seeding. Based on an analytical approach introduced by Sanitja and Goldstein (2004), the implemented convective flow exhibits an increase of the heat transfer around the sample with turbulence intensity. On the other hand, the relatively high Nusselt numbers at the front stagnation points decline gradually to reach

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a minimum value at Î¸ = 85 due to the increase of the thermal resistance with boundary layer growth. The numerical results of the crystal fractions are in agreement with NMR measurements and the obtained temperature values fit those of the Tsensors inside and around the sample.

Fig. 1: Temperature on the downwind point of the sample after 150 minutes of cooling tunnel operation.

Fig. 2: Evolution of stable crystal upon cooling at 65 minutes. High thermal conductivity of aluminum shell allows a symmetric crystallization.

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Institute of Computational Physics

1.22

Research Report 2015

Simulation Software for DSSC Modules

PECSIM is a simulation software developed at ICP for the analysis and optimization of dyesensitized solar cells (DSSCs). In collaboration with our industrial partner it is extended by a new toolbox for the simulation of large-scale modules and used to develop optimization strategies for their solar panels. Contributors:

M. Schmid, D. Bernhardsgrütter, J. Schumacher

Partners: Funding: Duration:

Glass2Energy SA, CSEM Alpnach, HEIG-VD, ISAAC-SUPSI CTI 2015–2016

The technology of DSSCs has been established in the 1990s at EPFL and is now on the brink of commercialization. It has a variety of advantages as e.g. transparency, exploitation of diffuse light and low production costs. These attractive features make them well suited for building-integrated photovoltaics (BIPV). Among the biggest challenges are long-term stability and the relatively low efficiency of DSSC modules. Our industrial partner Glass2Energy produces DSSC panels for the BIPV market. Their modules not only produce energy but also take the functions of façade, windows and decorations, see Fig. 1. Glass2Energy addressed stability issues by establishing the industrial manufacutre of glass sealing. With help of the PECSIM simulation software the power output of their product is improved.

Fig. 1: Transparent coloured photovoltaic cells manufactured by glass2energy presented at the universal exhibition Expo Milano 2015.

In order to build efficient DSSC modules it is necessary to optimize the series connection of the individual cells. For this purpose, a new simulation mode is implemented into the PECSIM software. It allows to investigate the DSSC module output for varying composition of the individual cells and module geometries. A quantitative loss analysis reveals the energy losses within each cell as well as efficiency losses due to upscaling from small cells to modules.

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Fig. 2: Qualitative comparison of the simulated power output of modules with optimal matched currents (Module 1) versus modules with bad matched currents of the individual cells (Module 2).

For a given configuration of the individual cells and a given module size, an optimization of the module geometry is feasible. For an ideal choice of the cellwidth ratio the currents of the back- and frontside oriented cells are matched, see Fig. 2. Additionally, variation of the cellsize entails two opposing effects on the module efficiency. It affects the power loss due to charge transport in the transparent conducting oxide as well as the dead area due to glass sealing. An equilibration of these losses leads to an optimal cellsize. In summary, we have an extended version of PECSIM at disposal which is ready to use for analysis and optimization of DSSC modules produced by Glass2Energy. We are currently working on the validation of our simulation model. As a next step in the ongoing project we target a statistical analysis of the most relevant parameters. Performance distributions are then calculated as a function of fabrication parameter distributions. In future this could eventually be incorporated into an inline quality control system via statistical process control based on the electrical performance of the products.

Zürcher Fachhochschule

Research Report 2015

1.23

Institute of Computational Physics

Coulometric system with generator cell

An automatic Coulometric measurement system for titration is developed. The system is based on a compact and easy-to-use cartridge system. The physical and chemical processes are summarized in a simulation model allowing for numerical electrochemical impedance spectroscopy. Contributors:

G. Sartoris, L. Holzer

Partners: Funding: Duration:

Mettler-Toledo AG, ZPP, IMPE, ICBC KTI 2014–2016

This project aims at developing an automatic, compact and easy-to-use measurement system for titration based on a cartridge system delivering the reagent and controlled by hardware. At ICP, we are concerned with the modeling and optimization of the generator cell. If during the first year, we were mainly concerned with geometric optimization, in the second one, we focused our attention on harmonic analysis by computing impedance spectra as a tool for model validation. Let us assume we want to titrate an acid and therefore at the working electrode (WE), we generate OH − hydroxide ions and at the zinc counter electrode (CE), we generate Zn+ ions. Between the analyte and the cartridge half-cell, there is an ion selective membrane which ideally should block all OH − and Zn+ ions and just allows passing some other anions A− from the analyte to the cartridge half-cell. So in the cartridge half-cell we have an in-flow current of Zn+ ions at the CE and in-flow current of A− at the membrane, but otherwise no other flow takes place over the boundary of the cartridge half-cell. For this model, the transport model is therefore given by the diffusion and migration of positive and negative charged carriers combined with the Poisson’s equation determining the electric potential. Non-resistive impedance spectra are caused by accumulation of charged carriers and for a titration cell these effects are taking place at inhomogeneous material interfaces, hence of primary importance is the form of the current injection at the electrical contacts. As an example Fig. 1 shows the Nyquist plot computed for a single carrier and some non-ideal current injection. The high frequency peak at 20 GHz is caused by the charged boundary layer acting as a capacitor and it is pretty invariant with respect to changing the domain’s size. The low frequency peak at 600 Hz is due to charge transport within the domain. However, for

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this bipolar model computed with actual parameters, the impedance spectra for both carriers cannot be evaluated, due to the adverse numerical condition caused by the very thin boundary layers of thickness ≈ 2×10−10 m. After these first numerical investigations, we arrived at the conclusion that a full fledged numerical model may not help to improve our understanding of the titration cell. Degradation effects influencing the contact surface charge are expected to have a major impact on the high-frequency peak, but this peak is out-of-measurability. If present, from measurements one can clearly identify the middlefrequency peak caused by the external doublelayer, but this peak is merely an input parameter and not a real outcome of our numerical model. At the end, one can just compare the measured and computed low-frequency diffusion range, however, even here we have a very adverse numerical situation due to a fluid phase with large ions concentrations and large dimensions. However, we note that there are examples where numerical impedance spectroscopy has been successfully applied, like for PEM fuel cells.

Fig. 1: Contribution to the Nyquist plot for a single carrier and a non-ideal contact.

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Institute of Computational Physics

1.24

Research Report 2015

Euler-Lagrangian model of particle laden flows and deposition effects in powder coating

In order to study the powder coating process of metal substrates, new means of processcharacterization have been devised and a comprehensive, numerical 3D Eulerian-Lagrangian model has been developed and qualitatively validated. Contributors:

G. Boiger, N. Reinke, S. Weilenmann, S. Hauri

Partners: Funding: Duration:

J. Wagner AG KTI 2015â&#x20AC;&#x201C;2016

The powder coating process is widely spread and commonly used in industry. However, knowledge about detailed phenomena and concerning parameter-effect relations remains of predominantly empirical nature. To create the foundation for future knowledge-based improvement efforts of the coating process, the ICP has developed numerical models and characterization methods concerning particle motion and deposition effects within flow- and electro-static fields.

simple coating experiment on a small metallic plate within our experimental coating chamber, as seen in Figure 2, and applications of our model on virtual recreations of the same procedure.

Fig. 2: Coating pistol, coating chamber and on-going coating procedure of a metal plate.

Fig. 1: Triangle chart of coating particle cloud state for three different parameter set-ups (red, green, blue curve) and various particle size classes (dots).

By comparing the dimensionless effects of acting gravity-, electro-static- and fluid- drag forces on particle motion, we were able to propose a new kind of characteristic triangle-chart notation as seen in Figure 1. An extensive, dynamic, Euler-Lagrange model of the coating procedure has been created as well. The model has been implemented in C++ within the open source CFD platform OpenFOAM, is transient in nature with respect to the applied LaGrangian particle implementation and the electro-static field calculation and is stationary regarding fluid-dynamic phenomena. We have conducted comparisons between a

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Fig. 3: Comparison of relative coating thickness measurements and corresponding simulations of the plate coating process.

Comparison of measured and simulated coating layer thicknesses, as seen in Figure 3, have shown a high degree of qualitative correspondence and have thus helped to validate the numerical model. Literature: G. Boiger, Eulerian-LaGrangian model of particleladen flows and deposition effects in electro-static fields based on OpenFOAM, to be published.

ZĂźrcher Fachhochschule

Research Report 2015

1.25

Institute of Computational Physics

Simulation von Heizelementen für Heissluftgebläse

In Heissluftgebläsen werden bis anhin Heizspiralen zur Erhitzung der Luftströmung genutzt. Für derartige Anwendungen soll ein optimiertes Verfahren entwickelt werden, um die Strömung effizienter aufzuheizen. Bevor jedoch eine Optimierung vorgenommen werden kann, müssen alle Parameter und Einflussfaktoren dieses multiphysikalischen Problems untersucht und verstanden werden. Contributors:

M. Boldrini, G. Boiger

Partners: Funding: Duration:

Leister KTI, Leister 2015–2017

Bei der Entwicklung neuer, optimierter Heizelemente für Heissluftgebläse ist es ausschlaggebend, dass die zugrundeliegenden physikalischen Vorgänge genau analysiert werden. Hierfür wurde ein 3D OpenFOAM Modell erstellt. Dieses soll die reale Geometrie eines einzelnen Heizkanals repräsentieren.

mung und den lokalen Eigenschaften des Fluides, auf die Luft übertragen.

Abb. 2: Wall Heat Flux und Geschwindigkeiten. Abb. 1: Schnitt durch Fluid Region.

Wir haben uns für den stationären, einphasigen, laminar-/turbulenten Wärmeübergangssolver chtMultiRegionSimpleFoam entschieden. Damit war es möglich, ein Modell zu entwickeln, welches sowohl die Strömung der Luft, als auch das Heizelement selbst auflöst. Über verschiedene Entwicklungsschritte wurde zuletzt die reale Geometrie eines Heizkanals relativ detailliert nachgebildet, Abb. 1. Hierbei wird Luft, als kompressibles Fluid durch einen Überdruck in das Simulationsgebiet eingeströmt. Innerhalb des Simulationsgebietes umströmt diese die Heizspirale im laminaren Regime. Die Heizspirale selbst wird als Festkörper simuliert, in welchem eine volums-spezifische, homogene Energiefreisetzung vorgegeben wird. Diese thermische Energie wird abhängig von der Strö-

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Mit dem Modell konnten alle physikalischen Einflussfaktoren auf den Heizvorgang des Fluides untersucht werden. Auch war es möglich den Temperaturverlauf innerhalb der Heizspirale zu untersuchen. Damit konnte gezeigt werden, welche Regionen in Bezug auf den thermischen Energieübergang am effektivsten sind. In einem weiteren Schritt wird es nun nötig, die physikalischen Eigenschaften des Fluides und des Heizelementes genauer zu spezifizieren. Ausserdem muss untersucht werden, ob der Einsatz eines Turbulenzmodells nötig ist. Literatur: H. G. Weller, G. Tabor, H. Jasak, C. Fureby, A tensorial approach to computational continuum mechanics using object-oriented techniques, Computers in Physics, 12, 6, 1998.

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Institute of Computational Physics

1.26

Research Report 2015

Optimierung von porösen Diaphragmen Modell- und simulationsunterstützte Materialentwicklung

Für eine pH-Messelektrode soll ein leistungsoptimiertes, keramisches Diaphragma entwickelt werden. Um die Zusammenhänge der physikalischen Einflüsse auf die Diaphragmaleistung besser zu verstehen und somit gezielt bestimmte Eigenschaften des Materials optimieren zu können, wird die vom IMPE durchgeführte Materialentwicklung durch Modellrechnungen von der Seite des ICP unterstützt. Contributors:

G. Boiger, T. Ott

Partners: Funding: Duration:

Mettler-Toledo, IMPE KTI 2014–2016

Die Leistung des Diaphragmas einer pHMesselektrode hängt erheblich von folgenden Haupteigenschaften ab: elektrische Leitfähigkeit sowie Ausflussgeschwindigkeit und –rate des Elektrolyten. Die Strömung und Leitfähigkeit des Diaphragmas wurden in einem semianalytischen Modell beschrieben, damit die Einflüsse der einzelnen Parameter auf die Optimierungskriterien untersucht werden können.

zahlreichen Material- und Prozessparametern abhängt. Zur Bestimmung der Einflussstärken der Parameter auf die Optimierungskriterien wurde in der Open Source CFD-Software OpenFOAM eine Parameterstudie an vereinfachten Geometrien (Rohr mit Bottleneck) durchgeführt. Variiert wurden die Länge und der Durchmesser des Bottleneck, der Skalierungsfaktor der Geometrie sowie die Druckdifferenz über die Probe und die Viskosität des Elektrolyten. Mit Hilfe dieser Studie konnte die optimale Porenform bestimmt werden. Parallel zur Parameterstudie wurde aus den CT-Daten einer realen Probe eine Simulationsgeometrie erstellt deren Resultate durch Messresultate validiert werden konnte.

Abb. 1: Im Improvement Space wird eine Materialprobe mit einer Referenzprobe verglichen.

Abb. 2: gezielte Materialoptimierung.

Die Optimierung kann auf verschiedene Weise erreicht werden, da die Gesamtleistung Ω von

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Abb. 3: Porengeometrie einer realen Probe.

Zürcher Fachhochschule

Research Report 2015

1.27

Institute of Computational Physics

Simulation des Nano-Dosierverhaltens von nicht-Newtonschen Flüssigkeiten

In der Pharmaindustrie ist es häufig notwendig Wirkstoffe im Nanoliterbereich zu dosieren. Da sich das experimentelle Studium des Dosierverhaltens solch geringer Mengen extrem schwierig gestaltet, wurde ein Modell erstellt, welches den Dosiervorgang simuliert. Bis anhin hat man sich auf newtonsche Fluide beschränkt. Das Modell wurde nun auf nichtnewtosche Fluide erweitert. Contributors:

M. Boldrini, S. Zangerl, G. Boiger

Partners: Funding: Duration:

Novartis ICP 2013–2016

Es wurde untersucht, wie man das nichtnewtonsche Dosierverhalten von Fluiden, welche in der Pharmaindustrie dosiert werden müssen, durch ein Modell abbilden kann. Zu Beginn wurden die nicht-newtonschen Modelleansätze, welche in OpenFOAM bereits implementiert sind auf ihre Eignung geprüft. Zunächst wurde das BirdCarreau Modell als vielversprechender Ansatz eingestuft. Jedoch musste man feststellen, dass dieses Modell nur für Fluide mit nicht extrem ausgeprägtem, nicht-newtonschen Verhalten geeignet ist.

decken zu können. Dem Modell sollten die Viskositätsmessungen, welche bis zu einer Scherrate von 104 s−1 durchgeführt werden konnten, und die Extrapolation nach Sisko zugrunde liegen. Hierfür wurde ein mehrteiliger Ansatz entwickelt. Dieser besteht einerseits aus einer Approximationsfunktion welche nach einem 5-Parameter-Modell an die Messkurve angenähert wird, sowie andererseits aus einer Extrapolationsfunktion nach Sisko, um höhere Scherratenbereiche abzudecken. Zwischen den beiden Funktionen ist eine Blendingfunktion geschaltet, welche den Übergang dieser Funktionen regelt.

Abb. 2: Viskositätsverteilung innerhalb des Einströmbereichs der Dosiernadel.

Abb. 1: Viskositätsverhalten verschiedener gemessener nicht-newtonscher Fluide.

Wie man in Abb. 1 erkennt, handelt es sich bei den zu dosierenden Fluiden aber um solche, welche ein teilweise extrem nicht-newtonsches Verhalten aufweisen. Somit wurde es notwendig ein eigenes Viskositätsmodell zu entwickeln, um den gesamten Viskositätsbereich der Fluide ab-

Zürcher Fachhochschule

Mit diesem Modell war es möglich, das Viskositätsverhalten aller gemessenen Fluide, zunächst qualitativ, nachzubilden. Hierdurch konnten auch die quantitativen Ergebnisse signifikant verbessert werden, jedoch musste man, aufgrund des gestiegenen Rechenaufwands auf ein einphasiges Modell umsteigen. Mit diesem Modell werden in einem nächsten Schritt viele, weitere Fluide simuliert und deren Dosierverhalten systematisch ausgewertet.

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Institute of Computational Physics

1.28

Research Report 2015

Nondestructive Quality and Process Control of Thermal Spray Coatings

Thermal spray coatings are used to increase resistance against mechanical, chemical and thermal wear. However, state-of-the-art testing methods cannot be used for continuous quality control during production. These methods are destructive, subjective and show low repeatability. In this project, a new method is developed for rapid, quantitative, nondestructive and repeatable in-situ measurement of porosity, thickness and thermal properties of thermal spray coatings. First results on samples from the industry partners show good correlation between the new and conventional methods. Contributors:

N. Reinke, A. Bariska, S. Hauri, T. Nguyen

Partners: Funding: Duration:

not disclosed KTI 2015â&#x20AC;&#x201C;2016

Thermal testing of coatings is based on monitoring dynamic heat diffusion on the surface of layered media after excitation with a light source in a reflection setup. The heat diffusion process is, in addition to the thickness of the coating, affected by thermal properties of the coating. Thus, under certain conditions, it is conversely possible to determine thermal properties of the coatings e.g. thermal coating resistance, thermal conductivity, thermal difffusivity, etc. as well as mechanical properties that correlate with the thermal properties, e.g. thickness and porosity. Thermal spray coatings are available with a wide variety of materials and applications processes. We focus on the following thermal spray coatings in this project: Yttrium-stabilized zirconia, sprayed with Atmospheric Plasma Spray (APS) process. These thermal barrier coatings are for example applied to blades in gas turbines, their main function is heat protection. Aluminum and chromium oxides, sprayed with High-Velocity Oxygen-Fuel (HVOF) process. The coatings are applied to steel substrates e.g. industrial rolls, their main function is wear protection. Tungsten carbides, sprayed

with High-Velocity Oxygen-Fuel (HVOF) process. The coatings are applied on piston rods, their main function is wear protection Low-alloyed carbon steel, sprayed with APS process on aluminum cylinder bores. Their main function is to reduce wear and lubricant usage. In a previous project, we showed that it is possible to simultaneously track changes in thickness and porosity using thermal testing of coatings. However, this required an optical coupling medium, which is not acceptable for industrial application. The main achievements of this new project are: accurate physical models of thermal spray coatings to compensate for the optical and infrared semi-transparency robust and efficient numerical algorithms to reliably extract information on porosity, thermal properties and coating thickness highly sensitive infrared detection system tuned to the infrared properties of the coatings optimized excitation source, see Fig. 1. The results of comparing conventional lab analysis with thermal testing of coatings shows good correlation.

Fig. 1: Comparison of porosity measurements on samples with conventional metallography versus thermal testing of coatings. The two methods correlate with R2 = 0.89. Thermal testing of coatings displays about three times smaller standard error than metallographic analysis.

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ZĂźrcher Fachhochschule

Research Report 2015

1.29

Institute of Computational Physics

Pulverbeschichten mit Closed-Loop Regelung

Das ICP hat zusammen mit Industriepartnern eine neue Technologie entwickelt, die die Pulverbeschichtung revolutionieren soll. Die Wagner-Geräte verfügen über eine hochgenaue Dosierungsautomatik, welche die Luftmenge zur Pulverförderung zu den Pulverpistolen permanent misst und regelt. Dadurch lassen sich dauerhaft konstante Werte sicherstellen. Aber, wie überprüft man verlässlich, dass diese Werte auch zur gewünschten Schichtdicke führen? Contributors: Partners: Funding: Duration:

A.Bariska, S.Hauri, B.Rutz, M.Torroni, B.Schmid, T.Nguyen, U.Vögeli, N.Reinke Winterthur Instruments AG, J. Wagner GmbH, Ronal AG, Ramseier Woodcoat AG KTI 2014–2015

Die Winterthur Instruments AG kennt schon lange das Bedürfnis ihrer Kunden, dauerhaft eine konstante Sollschichtdicke in möglichst engen Toleranzgrenzen realisieren zu können. Denn bisher war eine konstante Schichtdicke, bei der weder zu viel noch zu wenig Beschichtungsmaterial aufgetragen wurde, mehr oder weniger ein Zufallstreffer. Bisher wurde die Schichtdicke nach dem Einbrennen manuell gemessen. Zwischen dem Auftragen der Beschichtung und dem Messvorgang können allerdings einige Stunden vergehen, da der Pulverlack vorher noch im Ofen eingebrannt wird und danach auf Raumtemperatur abkühlen muss, um das Messgerät beim Aufsetzen nicht zu beschädigen. Wird dann beim Nachmessen einer Stichprobe eine Abweichung nach unten festgestellt, sind aller Wahrscheinlichkeit nach schon eine Reihe von Bauteilen unterbeschichtet worden. Aufgrund der stichprobenartigen Prüfung ist das Auffinden der fehlerhaft produzierten Teile schwierig und die Nacharbeit mit viel Aufwand verbunden. Wird beim Nachmessen einer Stichprobe eine Abweichung nach oben festgestellt, wird zu viel Pulver ap-

pliziert und damit Material verschwendet. Auch das kann nicht mehr rückgängig gemacht werden. Zu dicke Beschichtungen werden allerdings häufig in Kauf genommen, denn eine Unterbeschichtung, und damit mangelnde Qualität, soll auf jeden Fall verhindert werden. Diese Strategie führt dazu, dass zu hohe Materialkosten anfallen. Ein Rechenbeispiel mit Durchschnittswerten verdeutlicht, wie stark sich die Kosten für eine dauerhafte Überbeschichtung aufsummieren bzw. wie viel Einsparpotenzial eine lückenlose Schichtdickenüberwachung bietet. Um diese Einsparungen zu realisieren, braucht man allerdings ein Messsystem, das vor dem Einbrennen am laufenden Förderband misst und das aufgrund der Messung vor dem Einbrennen die Schichtdicken nach dem Einbrennen berechnen kann – den CoatMaster. Sind diese Voraussetzungen nun erfüllt, hat man einen großen Schritt in die Zukunft der Pulverbeschichtung ganz im Sinne der Industrie 4.0 gemacht: Es entsteht eine Pulverbeschichtungsanlage, die sich selbst regelt.

Fig. 1: Das Rechenbeispiel mit Durchschnittswerten verdeutlicht, wie viel Einsparpotenzial eine lückenlose Schichtdickenüberwachung bietet und was Beschichter in C pro Jahr sparen können. Der Berechnung liegen folgende Annahmen zugrunde: Pulverpreis = 5.00 C/kg, spezifisches Gewicht = 1.5 g/cm3.

Zürcher Fachhochschule

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Institute of Computational Physics

1.30

Research Report 2015

Qualitätssicherung von Haftvermittlerschichtdicken in der Produktion von Drehschwingungsdämpfern

Die Schichtdicke von Haftvermittlern liegt typischerweise zwischen 10µm und 20µm bei einem Einschichtsystem und zwischen 20 und 40µm bei einem System aus Primer und Cover. Bei Schichtdicken unterhalb dieses Toleranzfensters können Haftungsprobleme der Gummi-Metallverbindung auftreten und die Funktionsfähigkeit des Drehschwingungsdämpfers nicht gewährleistet werden. Bei zu hohen Schichtdicken können unter mechanischer Belastung des Bauteils sogar Risse innerhalb der Haftvermittlerschicht auftreten. Die produktionsbegleitende Schichtdickenmessung ist also ein wesentliches Qualitätskriterium zur Gewährleistung der Funktionstüchtigkeit von Drehschwingungsdämpfern. Contributors:

A.Bariska, S.Hauri, B.Rutz, M.Torroni, B.Schmid, T.Nguyen, U.Vögeli, N.Reinke

Partners: Funding: Duration:

Winterthur Instruments AG Winterthur Instruments AG 2014–2015

Radialschwingungen entstehen durch die stoßweise Kraftübertragung vom Kolben über Kolbenbolzen, Pleuelstange auf die Kurbelwelle und erzeugen kurzzeitige Drehmomentspitzen. Diese führen in Getrieben zu Geräuschentwicklungen und Verschleiß. Die Schwingungen belasten aber auch die Kurbelwelle mechanisch, wodurch es zu Torsionsbrüchen kommen kann. Die Aufgabe eines Drehschwingungsdämpfers liegt in der Dämpfung dieser Radialschwingungen. Der Drehschwingungsdämpfer besteht aus einer Sekundärmasse (Schwungring) und Primärmasse (Gehäuse). Der von Schwungring und Gehäuse eingeschlossene Raum wird von einem Gummi ausgefüllt.

Fig. 1: Schnitt durch einen Drehschwingungsdämpfer.

Bei der Herstellung der Drehschwingungdämpfer werden die Innenseiten von Schwungring und Gehäuse mit einem Haftvermittler beschichtet. Bei einem anschliessenden Vulkanisierungsprozess bei einer Temperatur von 120°C bis 160°C wird eine dauerhafte Verbindung von Schwungring, Gummierung und Gehäuse hergestellt.

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Bei funktionskritischen Qualitätskenngrössen ist eine kritische Beurteilung des verwendeten Prüfmittels durchzuführen. Dazu wurden in der Automobilindustrie die Qualitätsfähigkeitskenngrösse cg eingeführt. Nur Prüfmittel mit einem cg-Wert von über 1.33 dürfen nach diesem Standard in der Qualitätssicherung eingesetzt werden. Zur Prüfung von Schichtstärken von Haftvermittlern wurden in der Vergangenheit Wirbelstromoder magnet-induktive Messgeräte eingesetzt. Diese weisen auf gestrahlten und beschichteten Oberflächen eine Standardabweichung typischerweise von mehreren µm auf. Daraus ergeben sich bei Toleranzfenstern von 10µm oder 20µm cgWerte von deutlich unter 1.33. Diese Messgeräte sind also nicht für die Qualitätssicherung zugelassen. Seit 2015 setzen Hersteller von Drehschwingungsdämpfern den CoatMaster zur Qualitätssicherung ein und setzen somit die hohen Vorgaben von der Automobilindustrie um. Der CoatMaster misst berührungslos die Schichtdicken von Haftvermittlern bei einem Messfehler von 70nm (= 0.07µm). Dies entspricht einem cg-Wert von 1.5 und erfüllt damit die modernen Anforderungen der Automobilindustrie. Durch den Einsatz des CoatMasters zur Qualitätssicherung in der Produktion von Drehschwingungsdämpfern erbringen Hersteller von Drehschwingungsdämpfern für ihre Kunden einen wichtigen verlässlichen Nachweis der hohen Qualitätsstandards der Automobilindustrie.

Zürcher Fachhochschule

Research Report 2015

1.31

Institute of Computational Physics

Entwicklung eines Messgeräts für die praktische Anwendung der Thermischen Schichtprüfung an Kunst und Kulturgut

Die Thermische Schichtprüfung ist ein bildgebendes, berührungsloses und zerstörungsfreies Untersuchungsverfahren, das in der Industrie zur Lokalisierung, Visualisierung und Quantifizierung von verdeckten Schäden an beschichteten Oberflächen eingesetzt wird. In einer vorbereitenden KTI-Machbarkeitsstudie konnte nun aufgezeigt werden, dass das Verfahren auch in der Konservierung und Restaurierung ein grosses Potential hat. Es wurden zahlreiche Anwendungsmöglichkeiten nachgewiesen, wie z. B. das Aufspüren von Delaminationen an einer Malschicht, Fassung oder Lackierung. Des Weiteren wurde bereits ein Prototyp eines Messgeräts zur praktischen Anwendung des Verfahrens an Kunst und Kulturgut entwickelt. Im Rahmen des aktuellen KTI-Forschungsprojekts soll nun durch dessen gezielte Weiterentwicklung ein für KonservatorInnen geeignetes, einfach zu bedienendes Messinstrument geschaffen werden. Contributors:

A. Bariska, S. Hauri, B. Rutz, M. Torroni, B. Schmid, T. Nguyen, U. Vögeli, N. Reinke

Partners: Funding: Duration:

Winterthur Instruments AG und andere KTI 2015–2016

In der Industrie wird das Verfahren der Thermischen Schichtprüfung zur Qualitätskontrolle an Beschichtungen oder Verbundwerkstoffen eingesetzt. In der Konservierung und Restaurierung kommt es – abgesehen von einigen experimentellen Anwendungen – noch nicht zum Einsatz. Hier gab es bisher keine messtechnische Möglichkeit, Delaminationen aufzuspüren. Im Rahmen einer MA-Thesis und einer KTI-Machbarkeitsstudie wurde nun die Eignung des Verfahrens für diesen Bereich nachgewiesen. So kann es z.B. zur Lokalisierung von Lockerungen an der Malschicht eines Gemäldes, der Fassung einer Skulptur, der Lackierung eines Oldtimers oder einem furnierten Möbelstück eingesetzt werden. Des Weiteren eignet es sich zur Visualisierung von Unterzeichnungen, unter einer Malschicht verborgenen Insektenfrassgängen oder hohlstehenden Putzen und zur Überprüfung von Festigungsmassnahmen so-

wie zur Dokumentation und Beurteilung des Erhaltungszustands eines Kunstwerks. Es wird ein Prototyp für die praktische Anwendung der Thermischen Schichtprüfung im aktuellen Projekt weiterentwickelt, um einerseits die Zuverlässigkeit der Messergebnisse zu optimieren, deren Auswertung und Interpretation zu erleichtern und andererseits weitere Anwendungsgebiete zu erschliessen. Dazu gilt es, den Einfluss der Oberflächenbeschaffenheit in den Messergebnissen zu reduzieren, u.a. durch die Evaluation alternativer Anregungstechniken. Weiter soll erstmals eine tomografische Untersuchungsmethode basierend auf der Thermischen Schichtprüfung entwickelt werden, die Aussagen über die Tiefenlage eines Schadens ermöglicht. Die Messergebnisse werden zudem durch die Überlagerung mit den Bildern einer zusätzlichen Kamera (VIS) leichter zu interpretieren sein.

Fig. 1: Nadelholzbrett mit künstlichen Insektenfrassgängen und darüber liegendem Furnier, Putzabhebungen (1) und Putzausbesserung (2) an historischem Mauerwerk, Ölgemälde (BHM) mit Blasenbildung in der Malschicht im Normallicht (oben) und als Phasenbild (unten).

Zürcher Fachhochschule

www.zhaw.ch

Institute of Computational Physics

1.32

Research Report 2015

Blaues Licht aus neuen Materialien

Um kräftige Farben in einem OLED Fernseher zu erzeugen, werden Materialien benötigt, die tief-blaues Licht erzeugen können. An der Universität Zürich werden solche Materialien synthetisiert, und am ICP konnten erstmals OLEDs mit diesen neu entwickelten Materialien hergestellt werden. Students:

Quan Ky Ha, Naratip Sriutamayothin

Category: Bachelor of Science, Semesterprojekt Mentoring: K. Pernstich, M. Regnat, K. Venkatesan (Universität Zürich) Handed In: Dezember 2015 Vereinfacht gesprochen, entsteht das Licht in einer organischen Leuchtdiode (OLED) durch das Zusammentreffen der positiven und negativen Ladungen aus der Spannungsquelle. Damit aus den Ladungen tatsächlich Licht (und nicht Wärme) erzeugt wird, sind spezielle Emitter-Moleküle notwendig. Am Departement für Chemie der Universität Zürich forscht die Gruppe von Dr. Venkatesan an neuartigen Molekülen, die in einer OLED blaues Licht erzeugen können. Die Besonderheit dieser Moleküle besteht darin, dass sie das Element Gold verwenden, während vergleichbare Moleküle die noch teureren und selteneren Elemente Iridium oder Platin verwenden. Stabile blaue EmitterMoleküle sind im Markt sehr gefragt, und derzeit gibt es noch grossen Bedarf nach besseren Materialien. In dieser Zusammenarbeit wurden die weltweit erstmals synthetisierten Moleküle der Universität Zürich verwendet, um im hauseigenen Labor des Institute of Computational Physics OLEDs herzustellen. Die einzelnen Schichten wurden dazu aus Lösung abgeschieden oder durch thermisches Verdampfen aufgebracht. Eine grosse Schwierigkeit bestand darin, die richtige Material- und Schichtkombination zu finden, denn blaues Licht ist energiereicher als rotes oder grünes Licht, und dies stellt besondere Anforderungen an die einzel-

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nen Materialien in der OLED. Erfreulicherweise konnten funktionierende OLEDs hergestellt werden, und Abb. 1 zeigt das gemessene Spektrum des emittierten Lichts. Der Hauptanteil liegt bei 490 nm, das etwas langwelliger (grünlicher) ist als erwartet. In einem nächsten Schritt müsste man die Konzentration der EmitterMoleküle variieren, und auch ein anderes MatrixMaterial verwenden, um ein noch tieferes Blau zu erhalten. Die Messungen helfen dabei die weitere Entwicklung voranzutreiben, und die Resultate sollen auch in einer internationalen Zeitschrift veröffentlicht werden.

Abb. 1: Gemessenes Lichtspektrum der blauen OLED.

Zürcher Fachhochschule

Research Report 2015

1.33

Institute of Computational Physics

Herstellung von Perowskit-Solarzellen

Perowskit-Solarzellen sind eine vielversprechende Entwicklung, welcher in Zukunft ein hohes Potential an der Energiewende beizumessen ist. Ziel dieses Projektes war die Herstellung solcher Solarzellen auch an der ZHAW zu ermöglichen. Hiermit sollte der Grundstein für weitere Projekte auf diesem Gebiet gelegt werden. Students:

Jonas Dunst

Category: MSE Vertiefungsarbeit Mentoring: K. Pernstich Handed In: Februar 2016 Eine bemerkenswerte Errungenschaft der Perowskit-Solarzellen liegt darin, dass mit ihnen in verhältnismässig kurzer Forschungszeit bereits Effizienzen von über 20% erzielt wurden. Zudem ist der Energieaufwand für deren Herstellung weitaus geringer als jener für konventionelle Silizium-Zellen. Allerdings besitzen PerowskitSolarzellen auch noch einiges an Verbesserungsund Forschungspotential. So sind die Zellen meist nicht langzeitstabil und weisen eine Hysterese auf. Weiter stellt die Reproduzierbarkeit bereits im Labormassstab eine Herausforderung dar. Das langfristige Ziel wäre es, durch simulationsbasierte Charakterisierung dieses Solarzellentyps ein tieferes Verständnis für dessen Funktionsweise zu bekommen und dadurch zur Verbesserung beizutragen. Als ersten Schritt in diese Richtung sollte in diesem Projekt ein Herstellverfahren für Perowskit-Solarzellen gemäss aktuellem Stand der Forschung etabliert werden. Dies ist von Bedeutung, da zur Modellierung zuverlässige Messwerte von definierten Solarzellen notwendig sind. Bei messtechnischer Charakterisierung direkt nach der Herstellung in der Inertgas-Glovebox unseres Labors erübrigt sich eine Verkapselung und ein Transport der Zelle.

definieren, welcher homogene und feinkristalline Perowskit-Schichten liefert welche in Abb. 1 unten rechts dargestellt ist. Hiermit wurden im Anschluss Solarzellen produziert, welche mit dem Messgerät Paios der Firma Fluxim charakterisiert werden konnten. Dies ergab u.a. die in Abb. 2 dargestellte Strom-Spannungs-Kennlinie. Sie ist charakteristisch für eine Solarzelle, kommt aber noch nicht an die erzielten Rekordeffizienzen heran.

Abb. 1: Mikroskop Aufnahmen verschiedener Perowskite Kristallstrukturen.

Für dieses Vorhaben musste erst einmal grundlegendes Basiswissen auf diesem neuen Fachgebiet erarbeitet werden. Schliesslich konnten Herstellungsverfahren aus verschiedenen Publikationen auf ihre Eignung geprüft werden. Dabei stellte sich heraus, dass die Kontrolle des Kristallisationsprozesses der Perowskitschicht die grösste Herausforderung darstellt. In Abb. 1 sind Mikroskopaufnahmen einiger dieser Schichtstrukturen dargestellt. Schliesslich ist es gelungen einen Prozess zu

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Abb. 2: JV-Kennlinie der hergestellten Solarzellen.

www.zhaw.ch

Institute of Computational Physics

1.34

Research Report 2015

Modellbasierter Reglerentwurf für die Temperaturregelung eines Kryostaten

Für die Untersuchung von grundlegenden Mechanismen in organischen Leuchtdioden und Solarzellen müssen Bauteile oft auf -150◦ C oder tiefer gekühlt werden. Aus solchen Tieftemperaturmessungen lassen sich genaue Modelle der physikalischen Vorgänge ableiten. In dieser Arbeit wurde ein modellbasierter Regler für ein selbst gebautes Kühlgerät - einem so genannten Kryostaten - entwickelt, der sowohl die Kühlleistung also auch die Temperatur des Kryostaten exakt regelt, und somit das zu untersuchende Bauteil kühlt. Students:

Oliver Keller, Reto Meier

Category: Bachelor of Science, Semesterprojekt Mentoring: K. Pernstich, O. Fluder (IMS) Handed In: Dezember 2015 Ein erster Prototyp des Kryostaten wurde überarbeitet bis er die gewünschten Anforderungen erfüllte. Dieser wurde dann in einem komplexen Simulink-Modell abgebildet (siehe Abb. 1). Es wurden etliche Messungen durchgeführt um das Modell zu validieren. Das sehr genaue Modell erlaubt die Auslegung des Reglers am Modell durchzuführen, was sich als sehr ressourcensparend erwies. Abb. 1: Simulink Modell des Kryostaten.

Die Regelstrecke ist ein gekoppeltes System mit den beiden Stellwerteingängen „heating power for pressure“ um den flüssigen Stickstoff im Dewer zu erwärmen, um so einen Druck im Dewer zu erzeugen, der den Stickstoff in den Probenträger drückt, und „heating power“ der die Heizung des Probenträgers ansteuert. Als Messgrössen stehen der Druck im Dewer „actual pressure“ und die Temperatur des Probenträgers „actual temp“ zur Verfügung. Der Regler besteht somit aus zwei Pfaden für dieses gekoppelte System: eine Kaskade für die Druck- und Temperaturregelung im Dewer und ein Temperaturregler für den Probenträger mit Koppelung auf den ersten Regler.

Der verbesserte Kryostat konnte dank des optimierten Reglers den Temperatursollwert sehr genau erreichen: die Ist-Temperatur überschwingt um weniger als 0.4°C, und die statische Abweichung beträgt maximal 0.05°C. Es ist nicht nur möglich einzelne Temperaturwerte vorzugeben, sondern ebenfalls Temperaturrampen mit einer Steigung von bis zu 0.2°C/s zu fahren. Das Entwicklungsstadium des Kryostaten befindet sich zurzeit zwischen dem Prototypen und der Markteinführung. Bei der Entwicklung wurde auf niedrige Herstellkosten des Kryostaten und kostengünstige Elektronik-Ansteuerung geachtet. Eine Weiterentwicklung und Kommerzialisierung dieses Kryostaten ist in KTI Projekt-Zusammenarbeit mit Fluxim AG geplant.

Abb. 2: Gemessene Temperatur des Kryostaten. Die statische Regelgenauigkeit beträgt 0.05◦ C.

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Appendix A.1

Student Projects

L. A NGST, M. M ONEGO, Detection and characterisation of gold nanorods in biological tissue, Betreuer: M. Bonmarin, Firmenpartner: Dermolockin GmbH, Winterthur, Projektarbeit Systemtechnik. A. A RRIBAS, Simulation elektro-statischer Beschichtungsverfahren, Betreuer: G. Boiger, Firmenpartner: J. Wagner AG, Altstätten, Projektarbeit Energie und Umwelt. P. B ÖSCH , M. Z EHNDER, Hyperthermia therapy with nanorods - Designing an Infrared-LED excitation system, Betreuer: M. Bonmarin, Firmenpartner: Dermolockin GmbH, Winterthur, Bachelorarbeit Systemtechnik. D. B ALTA , M. S CHMID, Optimierung der Sekundärlufteindüsung in Verbrennungsöfen mittels thermisch-fluidischer CFD-Modellierung in openFOAM, Betreuer: T. Hocker, Firmenpartner: Umweltingenieurbüro I.C.E. AG, Wil, Bachelorarbeit Maschinentechnik. A. B LEULER , N. S ALIHI , J. S TORSKOGEN, Handgerät für die Messung von Schichtdicken im Baubereich, Betreuer: N. Reinke, Projektarbeit Systemtechnik. M. B OLDRINI, Simulation von hochfrequenten Dosiervorgängen mittels OpenFoam, Betreuer: G. Boiger, Firmenpartner: Novartis Pharma AG, Basel, Vertiefungsarbeit Master of Science. M. B RUMM, Development of a Sound Coding Algorithm for Optical Cochlear Implants, Coach: B. Ruhstaller, Master thesis for Master of Science in Engineering. S. D ICHT, I. M EULI, Weiterentwicklung eines Holzvergasungsreaktors, Betreuer: G. Boiger, Firmenpartner: Berchtold Apparatebau AG, Thalwil, Bachelorarbeit Maschinentechnik. J. D UNST, Fabrication and Characterization of Perovskite Solar Cells, Betreuer: K. Pernstich, B. Ruhstaller, Vertiefungsarbeit Master of Science in Engineering. C. E DELMANN , K. S IGNER, Effizienzsteigerung elektro-statischer Beschichtungsverfahren - Arbeit 2, Betreuer: G. Boiger, N.Reinke, Firmenpartner: J.Wagner AG, Altstätten, Bachelorarbeit Energie und Umwelt. S. E HRAT, C. W ERDENBERG, Aufbau eines Prüfstands für Druckverlustmessungen, Betreuer: T. Hocker, D. Meier, Firmenpartner: Hexis AG, Winterthur, Projektarbeit Energie und Umwelt. F. F RIES, Entwicklung eines mikroskopischen 3D-Kraftsensors, Betreuer: N. Reinke, Projektarbeit Systemtechnik. F. F RIES, Entwicklung einer hochauflösenden Mikrobolometer-Kamera, Betreuer: N. Reinke, Bachelorarbeit Systemtechnik.

Institute of Computational Physics

Research Report 2015

C H . H ABLÜTZEL , M. S CHWEIZER, Effizienzsteigerung elektro-statischer Beschichtungsverfahren Arbeit 1-2, Betreuer: G. Boiger, N. Reinke, Firmenpartner: J.Wagner AG, Altstätten, Bachelorarbeit Energie und Umwelt/Maschinentechnik. Q UAN K Y H A , N ARATIP S RIUTAMAYOTHIN, OLEDs aus neuen Materialien, Betreuer: K. Pernstich, M. Regnat, K. Venkatesan (Universität Zürich), Semesterprojekt. O LIVER K ELLER , R ETO M EIER, Modellbasierter Reglerentwurf für die Temperaturregelung eines Kryostaten, Betreuer: K. Pernstich, O. Fluder (IMS), Semesterprojekt. K. L APAGNA, Calculation of Light Scattering Distribution Functions based on Fourier and Microfacets Methods for 3D Textures, Coach: B. Ruhstaller, Master thesis for Master of Science in Engineering. J. M ARON, Entwicklung eines neuartigen Kupferelektrolyse Verfahrens mittels Simulation, Modellierung & experimenteller Validierung, Betreuer: G. Boiger, Firmenpartner: ICP intern, Projektarbeit Energie und Umwelttechnik. D. M EIER, Thermisch-fluidische Optimierung von Interkonnektoren von Brennstoffzellen vom Typ SOFC, Betreuer: T. Hocker, C. Meier, Firmenpartner: Hexis AG, Winterthur, Vertiefungsarbeit Master of Science. T. M ESAREC, Thermische Optimierung eines Lasttrennschalters, Betreuer: T. Hocker, Firmenpartner: Woehner AG, Rödental (D), Vertiefungsarbeit Master of Science. S. M EUNIER, Time resolved, wavelength selective electroluminescence measurement setup, Supervisor: P. Losio, Internship. E. M EYER, Entwicklung eines neuartigen Kupferelektrolyse Verfahrens - Rahmenbedingungen und Konstruktion, Betreuer: G. Boiger, Firmenpartner: ICP intern, Bachelorarbeit Maschinentechnik. F. M ÜLLER, Application Software for Large-Area Modeling of Photovoltaics and OLEDs, Coach: B. Ruhstaller, Master thesis for Master of Science in Engineering. T. OTT, Modellierung von Mikrostrukturparametern eines Diaphragmas zu PH Messung, mittels OpenFoam, Betreuer: G. Boiger, Firmenpartner: Mettler Toledo AG, Urdorf, Vertiefungsarbeit Master of Science. M. RUTZER , S. S IGG, Entwicklung einer neuen, thermischen Methode zur Hautkrebsbekämpfung, Betreuer: G. Boiger, M. Bonmarin, Firmenpartner: Dermolockin GmbH, Winterthur, Bachelorarbeit Energie und Umwelttechnik. J. F. S CHREYER , C. G RIESSER, Multispektrales Lebensmittel-Erkennungssystem, Betreuer: N. Reinke, Projektarbeit Systemtechnik. L. S TEPANOVA, 3D ray tracing algorithm for light outcoupling from microstructured OLEDs, Advisors: C. Kirsch, R. Knaack, B. Ruhstaller, Master thesis EPFL. S. W EILENMANN, Entwicklung eines neuartigen Kupferelektrolyse Verfahrens - Simulation und Modellierung, Betreuer: G. Boiger, Firmenpartner: ICP intern, Bachelorarbeit Maschinentechnik. S. Z ANGERL, Entwicklung eines mehrschichtigen, thermischen Hautmodells mittels OpenFoam, Betreuer: G. Boiger, Firmenpartner: Dermolockin GmbH, Winterthur, Vertiefungsarbeit Master of Science.

www.zhaw.ch

Zürcher Fachhochschule

Research Report 2015

A.2

Institute of Computational Physics

Scientific Publications

S. A LTAZIN , C. R EYNAUD, U. M. M AYER , T. L ANZ , K. L APAGNA , R. K NAACK , L. P ENNINCK , C. K IRSCH , K. P. P ERNSTICH , S. H ARKEMA , D. H ERMES , B. RUHSTALLER, Simulations, Measurements, and Optimization of OLEDs with Scattering Layer, SID Symposium Digest of Technical Papers, 46 (1), 564–567, 2015. S. A LTAZIN , C. R EYNAUD, U.M. M AYER , T. L ANZ , K. L APAGNA , R. K NAACK , L. P ENNINCK , C. K IRSCH , K.P. P ERNSTICH , S. H ARKEMA , D. H ERMES , B. RUHSTALLER, Simulations, Measurements, and Optimization of OLEDs with Scattering Layer, SID Symposium Digest of Technical Papers, 46 (1), 564-567, 2015. S. A LTAZIN , S. Z ÜFLE , L. P ENNINCK , B. RUHSTALLER, Combining Simulations and Experiments to Study the Impact of Polar OLED Materials, IMID Digest, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Moderne Qualitätssicherung bei Haftvermittlerschichten, Journal für Oberflächentechnik. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Schichtdickenmessung direkt nach dem Auftragen, Journal für Oberflächentechnik. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Closed-Loop-Regelung der Schichtstärke in Pulverbeschichtungsanlagen, Journal für Oberflächentechnik. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Viel Pulver sparen, mo Oberfläche. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Pulver mikrometergenau applizieren, besser lackieren. G. B OIGER, System Dynamic Modelling Approach for resolving the Thermo Chemistry of Wood Gasification, Int. J. of Multiphysics, 9 (2), 137–155, 2015. M. B ONMARIN , FA. L E G AL, A lock-in thermal imaging setup for dermatological applications, Skin Research and Technology, 21, 284–290, 2015. H. C HEN , O. M A , Y. Z HOU, Z. YANG , M. J AZBINSEK , Y. B IAN , N. Y E , D. WANG , H. C AO, W. H E, Engineering of Organic Chromophores with Large Second-Order Optical Nonlinearity and Superior Crystal Growth Ability, Crystal Growth and Design, 15, 5560–5567, 2015. O. D ÜRR , Y. PAUCHARD, D. B ROWARNIK , R. A XTHELM , M. L OESER, Deep Learning on a Raspberry Pi for Real Time Face Recognition, EG 2015 - Posters 11-12, 2015. S. J ENATSCH , T. G EIGER , J. H EIER , C. K IRSCH , F. N ÜESCH , A. PARACCHINO, D. R ENTSCH , B. RUHSTALLER , A. C. V ÉRON , R. H ANY, Influence of chemically p-type doped active organic semiconductor on the film thickness versus performance trend in cyanine/C60 bilayer solar cells, Science and Technology of Advanced Materials, 16 (3), 035003, 2015. S. J ENATSCH , T. G EIGER , J. H EIER , C. K IRSCH , F. N ÜESCH , A. PARACCHINO, D. R ENTSCH , B. RUHSTALLER , A.C. V ÉRON , R. H ANY, Influence of chemically p-type doped active organic semiconductor on the film thickness versus performance trend in cyanine/C60 bilayer solar cells, Science and Technology of Advanced Materials, Taylor & Francis, 2016. L. K ELLER , A. H OLGER , I. M ANKE, Impact of sand content on solute diffusion in Opalinus Clay, Applied Clay Sciences, 134, 134–142, 2015.

Zürcher Fachhochschule

www.zhaw.ch

Institute of Computational Physics

Research Report 2015

L. K ELLER, On the representative elementary volumes of clay rocks at the mesoscale, Journal of Geology and Mining Research, 7, 58–64, 2015. L. K ELLER , L. H OLZER , P. G ASSER , R. E RNI , M. R OSSELL, Intergranular pore space evolution in MX80 bentonite during a long-term experiment, Applied Clay Sciences, 104, 150–159, 2015. J. T. K IM , O. P. K WON , F. D. J. B RUNNER , M. J AZBINSEK , S. H. L EE , P. G UNTER, Phonon Modes of Organic Electro-Optic Molecular Crystals for Terahertz Photonics, Journal of Physical Chemistry C, 119, 10031–10039, 2015). J. T. K IM , O. P. K WON , M. J AZBINSEK , Y. C. PARK , Y. S. L EE, First-Principles Calculation of Terahertz Absorption with Dispersion Correction of 2,2 ‘-Bithiophene as Model Compound, Journal of Physical Chemistry C, 12598–12607, 2015. E. K NAPP, B. RUHSTALLER, Analysis of negative capacitance and self-heating in organic semiconductor devices, J. Appl. Phys., 117, 135501, 2015. T. L ANZ , K. L APAGNA , S. A LTAZIN , M. B OCCARD, F.J. H AUG , C. B ALLIF, B. RUHSTALLER, Light trapping in solar cells: numerical modeling with measured surface textures, Optics express, 23 (11), A539-A546, 2015. S. H. L EE , B. J. K ANG , J. S. K IM , B. W. YOO, J. H. J EONG , K. H. L EE , M. J AZBINSEK , J. W. K IM , H. Y UN , J. T. K IM , Y. S. L EE , F. R OTERMUND, O. P. K WON, New Acentric Core Structure for Organic Electrooptic Crystals Optimal for Efficient Optical-to-THz Conversion, Advanced Optical Materials, 3, 756–762, 2015. S. H. L EE , B. W. YOO, M. J AZBINSEK , B. J. K ANG , F. R OTERMUND, O. P. K WON, Organic ionic electro-optic crystals grown by specific interactions on templates for THz wave photonics, CrystEngComm 17, 4781–4786, 2015. S. H. L EE , B. W. YOO, H. Y UN , M. J AZBINSEK , O. P. K WON, Organic styryl quinolinium crystal with aromatic anion bearing electron-rich vinyl group, Journal of Molecular Structure, 1100, 359– 365, 2015. M. L INDER , T. H OCKER , C. M EIER , L. H OLZER , K.A. F RIEDRICH , B. I WANSCHITZ , A. M AI , J.A. S CHULER, A model-based approach for current voltage analyses to quantify degradation and fuel distribution in solid oxide fuel cell stacks, Journal of Power Sources, 288, 409–418, 2015. M. L INDER , T. H OCKER , L. H OLZER , O. P ECHO, K.A. F RIEDRICH , T. M ORAWIETZ , R. H IES GEN , R. KONTIC, B. I WANSCHITZ , A. M AI , J.A. S CHULER , Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects, Solid State Ionics, 283, 38– 51, 2015. P. L OSIO,O. C AGLAR ,J. C ASHMORE , J. H ÖTZEL , S. R ISTAU, J. H OLOVSKY, Z. R EMES , I. S INICCO, Light management in large area thin-film silicon solar modules, Solar Energy Materials and Solar Cells, 143, 375–385, 2015. J. L UO, Z. L I , S. N ISHIWAKI , M. S CHREIER , M. M AYER , P. C ENDULA , Y. H. L EE , K. F U, A. C AO, M. K. N AZEERUDDIN , Y. E. R OMANYUK , S. B UECHELER , S. T ILLEY, L. .H. W ONG , M. G RÄTZEL, Targeting Ideal Dual-Absorber Tandem Water Splitting Using Perovskite Photovoltaics and CuInx Ga1-xSe2 Photocathodes, Advanced Energy Materials, 5, 2015. O. P ECHO, A. M AI , B. M ÜNCH , T. H OCKER , R. F LATT, L. H OLZER, 3D Microstructure Effects in Ni-YSZ Anodes: Influence of TPB Lengths on the Electrochemical Performance, Materials, 8, 7129–7144, 2015.

www.zhaw.ch

Zürcher Fachhochschule

Research Report 2015

Institute of Computational Physics

O. P ECHO, L. H OLZER , Z. YANG , J. M ARTYNCZUK , T. H OCKER , R. F LATT, M. P RESTAT, Influence of strontium-rich pore-filling phase on the performance of La0.6 Sr0.4 CoO3−δ thin-film cathodes, Journal of Power Sources, 274, 295–303, 2015. O. P ECHO, O. S TENZEL , B. I WANSCHITZ , P. G ASSER , M. N EUMANN , V. S CHMIDT, M. P RESTAT, T. H OCKER , R. F LATT, L. H OLZER, 3D Microstructure Effects in Ni-YSZ Anodes: Prediction of Effective Transport Properties and Optimization of Redox Stability, Materials, 8, 5554–5585, 2015. N. R EINKE, Was ist Licht?, Aktuelle Technik, 2015. Y. S AFA , T. H OCKER, A validated energy approach for the post-buckling design of micro-fabricated thin film devices, Applied Mathematical Modelling, 39, 483–499, 2015. S. Z ÜFLE , M. N EUKOM , S. A LTAZIN , M. Z INGGELER , M. C HRAPA , T. O FFERMANS , B. RUH STALLER , An Effective Area Approach to Model Lateral Degradation in Organic Solar Cells, Adv. Energy Mater. 5, 1500835, 2015.

A.3

Book Chapters

A. K HARAGHANI , C. K IRSCH , T. M ETZGER , E. T SOTSAS, Liquid Distribution and Structural Changes During Convective Drying of Gels, In Colloid Process Engineering, Editors M. Kind, W. Peukert, H. Rehage, H. P. Schuchmann; Springer, 93–112, 2015.

A.4

News Articles

M. Bonmarin, Hautkrankheiten mit Hightech-Verfahren aufspüren, Impact Magazine, Dezember, 2015. T. Hocker, Perfecting the chocolate making process, International Innovation, December, 2015. A. Bariska, S. Hauri, B. Rutz, M. Torroni, B. Schmid, T. Nguyen, U. Vögeli, N. Reinke, Elektrostatische Pulverbeschichtung mit Closed-Loop Regelkreis, mo Oberfläche, 2015.

A.5

Conferences and Workshops

S. A LTAZIN , C. R EYNAUD, U. M AYER , L. P ENNINCK , K. L APAGNA , T. L ANZ , C. K IRSCH , R. K NAACK , K. P ERNSTICH , S. H ARKEMA , D. H ERMES , B. RUHSTALLER, Scattering particle layers for light extraction in OLEDs: numerical design and experiment, International Meeting on Information Display IMID, Daegu, 2015. S. A LTAZIN , L. P ENNINCK , C. R EYNAUD, U. M. M AYER , K. L APAGNA , T. L ANZ , C. K IRSCH , R. K NAACK , K. P ERNSTICH , B. RUHSTALLER , S. H ARKEMA , D. H ERMES, Simulations, measurements and optimization of OLEDs with scatter layer, SID International Symposium, San Jose, 2015. R. A XTHELM, A finite element simulation of high density pedestrian flow, TGF15 Traffic and Granular Flow, Delft, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Zerstörungsfreie Prüfung von Faserverbundbauteilen, Stuttgarter Produktionsakademie Fraunhofer Zürcher Fachhochschule

www.zhaw.ch

Institute of Computational Physics

Research Report 2015

IPA, Stuttgart, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Berührungslose Schichtdickenmessung von Nass- und Pulverlacken, Winterthurer Lack und Farben Symposium, Winterthur, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Industrie 4.0 in der Oberflächentechnik - Fallstudien, Winterthurer Oberflächentag, Winterthur, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Berührungslose Schichtdickenmessung in der Lackentwicklung, European Coatings Show, Nürnberg, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Zerstörungsfreie Schicht- und Werkstoffprüfung, Control, Stuttgart, 2015. A. B ARISKA , S. H AURI , B. RUTZ , M. TORRONI , B. S CHMID, T. N GUYEN , U. VÖGELI , N. R EINKE, Closed-Loop Beschichtung durch kontinuierliche Schichtdickenmessung, EPS Pulvertreff, München, 2015. G. B OIGER, OpenFoam based Modeling of Particle Motion and Deposition Processes in Electro Static Fields, 10th Int. Conference of Multiphysics, London, 2015. M. B ONMARIN , L. H OLZER, On the potential of active thermal imaging for skin cancer diagnostic, 25. Deutscher Hautkrebskongress, München, 2015. M. B ONMARIN , L. H OLZER , B. M UENCH , B. S CHMID, Aktive Thermographie für Hautkrebs Diagnose, 25th Deutscher Hautkrebskongress der Arbeitsgemeinnschaft Dermatologische Onkologie ADO, München, 2015. L. C APONE , L. H OLZER , A. L AMIBRAC, J. D UJC, O. S TENZEL , F. N. B ÜCHI , J. S CHUMACHER, Voxel-based modelling of water distribution in PEM porous media, 12th Symposium on Fuel Cell and Battery Modelling and Experimental Validation – ModVal 12, Freiburg, 2015. L. C APONE , A. L AMIBRAC, J. S CHUMACHER, A novel Monte Carlo technique for simulating liquid water distribution in gas diffusion layers of PEFCs, 2nd SCCER-Mobility Annual Conference, Zürich, 2015. ¨ , J. S CHUMACHER , Voxel-based modeling of L. C APONE , L. H OLZER , A. L AMIBRAC, F. B U CHI water distribution in PEM porous media, 12th Symposium on Fuel Cell and Battery Modelling and Experimental Validation – ModVal 12, Freiburg am Brisgau, 2015. ¨ , A novel Monte Carlo scheme L. C APONE , A. L AMIBRAC, J. D UJC, J. S CHUMACHER , F. B U CHI for liquid water distribution in gas diffusion layers of PEFCs, Annual Conference SCCER Mobility, Zürich, 2015.

P. C ENDULA , L. S TEIER , S. T ILLEY, M. M AYER , M. G RÄTZEL , J. S CHUMACHER, Optoelectronic Modeling of Hematite Photoelectrodes, 12th Symposium on Modeling and Experimental Validation of Fuel Cells and Batteries, Freiburg am Breisgau, 2015. P. C ENDULA , L. S TEIER , S. T ILLEY, M. M AYER , M. G RÄTZEL , J. S CHUMACHER, Optoelectronic Modeling of Hematite Photoelectrodes, Solar Fuel Conference : Light Driven Water Splitting Using Semiconductor Based Devices, Mallorca, 2015. P. C ENDULA , L. S TEIER , S. T ILLEY, M. M AYER , M. G RÄTZEL , J. S CHUMACHER, Optoelectronic Modeling of Hematite Photoelectrodes, 1st International Solar Fuel Conference, Uppsala, 2015. www.zhaw.ch

Zürcher Fachhochschule

Research Report 2015

Institute of Computational Physics

M. D OLD, T. H OCKER , M. L INDER , L. H OLZER , A. M AI , J. A. S CHULER, Model-based analysis of electrochemical impedance spectra of solid oxide fuel cells, 12th Symposium for Fuel Cell and Battery Modeling and Experimental Validation ModVal 12, Freiburg, 2015. J. D UJC, M. C OCHET, A. F ORNER C UENCA , L. C APONE , J. S CHUMACHER , P. B OILLAT, 3D simulation of membrane electrode assembly with hydrophilic treated GDL, 2nd SCCER-Mobility Annual Conference, Zürich, 2015. J. D UJC, L. C APONE , J. S CHUMACHER , J. B IESDORF, P. B OILLAT, Numerical simulation of liquid water saturation in cathode side gas diffusion layers of PEFCs, 12th Symposium on Fuel Cell and Battery Modelling and Experimental Validation – ModVal 12, Freiburg am Brisgau, 2015. G. F RITSCHER , S. KOGLER T. H UBER , A. O PITZ , J. F LEIG , A. H EEL , D. B URNAT, L. H OLZER, Electrochemical properties of La0.2 Sr0.7 TiO3 thin film electrodes under reducing conditions, EMRS – European Materials Research Society Spring Meeting, Lille, 2015. J. F UCHS , G. B OIGER , C. M EIER , R. D ENZLER, Simulation of heat transfer processes within a fuel cell system based on OpenFoam, 12th Symposium for Fuel Cell and Battery Modeling and Experimental Validation - ModVal 12, Freiburg, 2015. M. G ORBAR , Y. D E H AZAN , D. P ENNER , L. H OLZER , G. B OIGER , R. J. C ERVERA , I. A. S CHNEI DER, Extrusion of YSZ diaphragms with controlled porosity used as liquid junction in pH electrodes, 14th Int. Conf of Europ. Ceram. Soc. ECERS, Toledo, 2015. A. H EEL , L. H OLZER ET AL ., CO2 Reduction & Reuse – Renewable Fuels for Efficient Electricity Production, NRP70 Kick-off Meeting, Lucerne, 2015. A. H EEL , R. KONTIC, L. H OLZER , P. S TEIGER , D. F ERRI , M. N ACHTEGAAL , O. K RÖCHER , H. M A DI , J. VAN H ERLE , J. A. S CHULER , A. M AI , SERAN – Self-Regenerating Smart Materials for Solid Oxide Fuel Cells, 1st Biomass for Swiss Energy Future Conference, Villigen, 2015. T. H OCKER, Teilnehmer an Podiumsdiskussion, Tagung über den Energiediskurs in der Schweiz, ZHAW, Departement für Angewandte Linguistik, Winterthur, 2015. L. H OLZER AND T. H OCKER, Influence of Coffee-Bed Microstructure on Extraction and Quality, Swiss Food Research Meeting, Wädenswil, 2015. L. H OLZER, Understanding the influence of electrode microstructure: methods and applications, 3rd Int. Workshop on degradation issues of Fuel Cells and Electrolysers (3rd DegIs), Santorini, 2015. E. K NAPP, B. RUHSTALLER, Analysis of Self-Heating and Negative Capacitance in Organic Semiconductors Devices, SID Display Week Technical Symposium, San Jose, 2015. E. K NAPP, B. RUHSTALLER, Analysis of self-heating and trapping in organic semiconductor devices, SPIE Optics + Photonics, San Diego, 2015. E. K NAPP, The Role of Self-Heating in the Electrical Characterization of Organic Semiconductors Devices, Theoretical Challenges in Organic Electronics, Heidelberg, 2015. M. L INDER , T. H OCKER , C. M EIER , L. H OLZER , A. K. F RIEDRICH , B. I WANSCHITZ , A. M AI , J. A. S CHULER, Quantification of SOFC stack degradation and fuel distribution based on current voltage data, 12th Symposium for Fuel Cell and Battery Modeling and Experimental Validation ModVal 12, Freiburg, 2015.

Zürcher Fachhochschule

www.zhaw.ch

Institute of Computational Physics

Research Report 2015

P. L OSIO, Simulation of Thin Film Silicon Solar Cells in industry, 8th Annual Meeting on Photonic Devices, Berlin, 2015. ˇ V. O RAVA , O. S OU CEK , P. C ENDULA, Modeling of Non-isothermal Reacting Flow in Fluidized Bed Reactors, Comsol Conference, Grenoble, 2015. ˇ V. O RAVA , O. S OU CEK , P. C ENDULA , J. .O. S CHUMACHER , L. G UBLER, Multi-phase modeling of a hydrogen generator coupled to a PEM fuel cell, 12th Symposium on Modeling and Experimental Validation of Fuel Cells and Batteries, Freiburg am Breisgau, 2015. ˇ V. O RAVA , O. S OU CEK , P. C ENDULA, Generalization of a multi-phase modeling of fluidized bed reactors, Multiphase Flow 2015, Valencia, 2015.

O. P ECHO, O. S TENZEL , B. I WANSCHITZ , R. J. F LATT, T. H OCKER , L. H OLZER, Improved redoxstability of Ni-YSZ anodes based on 3D microstructure and experimental analyses, 12th International Conference on Materials Chemistry (MC12), University of York, 2015. O. P ECHO, O. S TENZEL , M. N EUMANN , B. I WANSCHITZ , V. S CHMIDT, T. H OCKER , R. J. F LATT, L. H OLZER, Optimization of redox stability and electrochemical performance of Ni-YSZ anodes based on detailed 3D microstructure analyses, Materials and Processes Graduate Symposium, ETH Zürich, 2015. K. P ERNSTICH, Organische Halbleiter für grossflächige Elektronik Anwendungen, Winterthurer Lack- und Farbensymposium 2015, Winterthur, 2015. B. RUHSTALLER, Insights from Advanced Characterization and Modeling of Organic and Perovskite Solar Cells, Intl. Symposium on Organic Solar Cell Stability (ISOS-8), Rio de Janeiro, 2015. B. RUHSTALLER, Combining Simulations and Experiments to Study the Impact of Polar OLED Materials, Japan OLED Forum, Chiba University, 2015. Y. S AFA, Developed model of the phase change kinetics in cocoa butter, simulation of cooling and solidification processes. , "AK-Schoko Treffen" Meeting Day of Swiss Chocolate Industry, ETHZürich, 2015. J. S CHUMACHER , J. D UJC, L. C APONE , O. S TENZEL , L. H OLZER , A. L AMIBRAC, F. N. B ÜCHI, Parameterisation of macrohomogeneous models of proton exchange membrane fuel cells, 12th Symposium on Fuel Cell and Battery Modelling and Experimental Validation – ModVal 12, Freiburg, 2015. S. Z ÜFLE , M. N EUKOM , S. A LTAZIN , T. O FFERMANS , M. C HRAPA , B. RUHSTALLER, Humidity induced lateral degradation in Organic Solar Cells investigated by measurements and simulation, HOPV Conference, Rome, 2015. S. Z ÜFLE , M. N EUKOM , T. L ANZ , M. Z INGGELER , M. C HRAPA , T. O FFERMANS , J. R EINHARDT, U. W ÜRFEL , B. RUHSTALLER, A 2D model for water diffusion in organic solar cells leading to lateral degradation, EMRS, Lille, 2015. S. Z ÜFLE , M. N EUKOM , S. A LTAZIN , T. O FFERMANS , M. HRAPA , B. RUHSTALLER, Humidity induced lateral degradation in Organic Solar Cells investigated by measurements and simulation, EMRS, Lille, 2015. S. Z ÜFLE , M. N EUKOM , S. A LTAZIN , B. RUHSTALLER, Combined Simulation and Electrical Characterization for OPV Stability Analysis, COST StableNextSol Meeting, Lille, 2015. S. Z ÜFLE , M. N EUKOM , B. RUHSTALLER, Complementary techniques to investigate degradation mechanisms in solar cells, PV Reliability Conference of the SwissPhotonics Network, Lugano, www.zhaw.ch

Zürcher Fachhochschule

Research Report 2015

Institute of Computational Physics

2015.

A.6

Public Events

B. F URRER , T. H OCKER , J. M USIOLIK , N. R OSENBERGER, 2. Brennstoffzellenforum, Winterthur, Juni 2015. N. R EINKE , A. B ARISKA, Winterthurer Oberflächentag 2014, Winterthur, Juni 2015. ¨ , L. H OLZER , L. C APONE , A. L AMIBRAC, J. D UJC , NFP70 Site Visit, J. S CHUMACHER , F. B U CHI Winterthur, November 2015.

A.7

Patents

R. D ENZLER , A. M AI (H EXIS AG), C. M EIER (ICP), Brennstoffzellenmodul und Verfahren zum Betrieb eines Brennstoffzellenmoduls, Patent pending, Munich, 2015.

A.8

Prizes and Awards

The ICP spin-off Dermolockin GmbH was finalist of the Heuberger Jungunternehmer-Preis and received a cash prize of 50’000 CHF. The Swiss Federal Foundation for Promotion of the National Economy through Scientific Research supported the ICP spin-off Dermolockin GmbH with an interest-free loan of 100’000 CHF. Winterthur Instruments ist Finalist im Export Award des Switzerland Global Enterprise.

A.9

Teaching

R. A XTHELM, Analysis 1, HS15, Bachelor of Science. R. A XTHELM, Lineare Algebra 2, FS15, Bachelor of Science. R. A XTHELM, Numerik, HS15, Bachelor of Science. G. B OIGER, Numerik 1 für IT, HS15, Bachelor of Science. G. B OIGER, Systemphysik für Aviatik 1 – Praktikum, HS15, Bachelor of Science. G. B OIGER, Systemphysik für Aviatik 2 – Praktikum, FS15, Bachelor of Science. G. B OIGER, Advanced Thermodynamics, HS15, Master of Science in Engineering. G. B OIGER, EVA Thermofluiddynamik Modellentwicklung in OpenFoam 1, FS15, Master of Science in Engineering. G. B OIGER, EVA Thermofluiddynamik Modellentwicklung in OpenFoam 2, HS15, Master of Science in Engineering.

Zürcher Fachhochschule

www.zhaw.ch

Institute of Computational Physics

Research Report 2015

G. B OIGER, Heat and mass transfer with two-phase flow, FS15, Master of Science in Engineering. M. B ONMARIN, Physik I für Systemtechnik, HS15, Bachelor of Science. M. B ONMARIN, Physik II für Maschinentechnik, FS15, Bachelor of Science. M. B ONMARIN, Physik I für Systemtechnik – Praktikum, HS15, Bachelor of Science. M. B ONMARIN, Physik II für Maschinentechnik – Pratktikum, FS15, Bachelor of Science. T. H OCKER, Fluid- und Thermodynamik 1, FS15, Bachelor of Science. T. H OCKER, Fluid- und Thermodynamik 2, HS15, Bachelor of Science. T. H OCKER, Systemphysik für Aviatik 1 – Praktikum, HS15, Bachelor of Science. M. J AZBINSEK, Numerik für Energie und Umwelttechnik – Praktikum, Bachelor of Science. M. J AZBINSEK, Physik für Energie und Umwelttechnik 2, Bachelor of Science. M. J AZBINSEK, Physik für Maschinentechnik 2, Bachelor of Science. C. K IRSCH, Mathematik: Analysis für Ingenieure 4, FS15, Bachelor of Science. C. K IRSCH, Mathematik: Lineare Algebra für Ingenieure 1, HS15, Bachelor of Science. C. K IRSCH, Mathematik: Analysis für Ingenieure 3, 2HS15, Bachelor of Science. C. M EIER , J. S CHUHMACHER, Brennstoffzellen und Verbrennung, HS15, Bachelor of Science. K. P ERNSTICH, Physik und Systemwissenschaft in Aviatik 1 – Praktikum, Bachelor of Science. K. P ERNSTICH, Physik und Systemwissenschaft in Aviatik 2 – Praktikum, Bachelor of Science. J. S CHUMACHER, Analysis für Ingenieure HS15, Bachelor of Science. J. S CHUMACHER, Physik 2 FS15, Bachelor of Science. J. S CHUMACHER, Multiphysics Modelling and Simulation FS15, Master of Science in Engineering. J. S CHUMACHER, Numerical Simulation of Solar Cells FS15, Master Online Photovoltaics. M. S CHMID, Mathematik: lineare Algebra für Ingenieure 1, Bachelor of Science. M. S CHMID, Mathematik: lineare Algebra für Ingenieure 2, Bachelor of Science.

www.zhaw.ch

Zürcher Fachhochschule

Research Report 2015

Z端rcher Fachhochschule

Institute of Computational Physics

www.zhaw.ch

Institute of Computational Physics

A.10

Research Report 2015

Spin-off Companies

www.nmtec.ch Numerical Modelling GmbH works in the field of Computer Aided Engineering (CAE) and offers services and simulation tools for small and medium enterprises. Our core competence is knowledge transfer where we bridge the gap between scientific know-how and its application in the industry. With our knowledge from physics, chemistry and the engineering sciences we are able to support your product development cycle and to conform to yours time and budget constraints. We often create so-called customer specific CAE tools in which the scientific knowledge required for your product is embedded. In this form, it is easily deployed within your R&D department and supports actual projects as well as improving the skills of your staff. Ask for our individual consulting service which covers all areas of scientific knowledge transfer without obligation.

www.fluxim.com FLUXiM AG is a provider of device simulation software to the display, lighting, photovoltaics and electronics industries worldwide. Our principal activity is the development and the marketing of the simulation software SETFOS designed to simulate the light emission from thin film devices such as organic light-emitting diodes (OLEDs), thin film solar cells (organic and inorganic) and organic semiconducting multilayer systems. Our software products are used worldwide in industrial and academic research labs for the study of device physics and product development. Check out our references and testimonials for more info. We develop software in Switzerland and in addition we provide services such as consulting, training and software development.

www.winterthurinstruments.ch Winterthur Instruments AG develops measurement systems for fast non-contact and non-destructive testing of industrial coatings. These measurement systems can be used to determine coating thicknesses, material parameters, e. g. porosity and contact quality, e. g. to detect delamination. The system is based on optical-thermal measurements and works with all types of coating and substrate materials. Our measurement systems provide the unique opportunity of non-contact and non-destructive testing of arbitrary coatings on substrates.

www.dermolockin.com Dermolockin GmbH is a recently founded spin-off company developing active thermography-based setups for dermatological applications. The main focus lies in the detection and characterization of cutaneous cancerous lesions with lock-in thermal imaging methods.

www.zhaw.ch

Z端rcher Fachhochschule

Research Report 2015

A.11

Institute of Computational Physics

ICP-Team

Name

Function

e-Mail

Dr. Rebekka Axthelm Andor Bariska Dr. Tilman Beierlein David Bernhardsgrütter Dr. Gernot Boiger Marlon Boldrini Dr. Mathias Bonmarin Dr. Peter Cendula Teresa D’Onghia Dr. Jaka Dujc Jonas Dunst Josef Fuchs Samuel Hauri Prof. Dr. Thomas Hocker Dr. Lorenz Holzer Dr. Mojca Jazbinsek Dr. Lukas Keller Dr. Christoph Kirsch Dr. Evelyne Knapp Kevin Lapagna Dr. Paolo Losio Philip Marmet Christoph Meier Martin Neukom Tan Thai Nguyen Vit Orava Tobias Ott Omar Pecho Dr. Kurt Pernstich Markus Regnat Prof. Dr. Nils Reinke Claude Ritschard Prof. Dr. Beat Ruhstaller Benjamin Rutz Dr. Yasser Safa Dr. Guido Sartoris Benjamin Schmid Dr. Matthias Schmid Prof. Dr. Jürgen Schumacher Esther Spiess Moreno Torroni Urs Vögeli Stephan Weilenmann Dr. Andreas Witzig Simon Züfle

Lecturer Research Assistant Research Assistant Research Assistant Lecturer Research Assistant Lecturer Research Associate Administrative Assistant Research Associate Research Assistant Research Assistant Research Associate Lecturer Research Associate Lecturer Research Associate Research Associate Research Associate Research Associate Research Associate Research Associate Research Associate Research Assistant Research Associate Research Assistant Research Assistant Research Associate Lecturer Research Assistant Lecturer Research Assistant Lecturer Research Assistant Research Associate Research Associate Research Assistant Lecturer Lecturer Administrative Assistant Research Assistant Research Assistant Research Assistant Lecturer, Head ICP Research Assistant

rebekka.axthelm@zhaw.ch andor.bariska@zhaw.ch tilman.beierlein@zhaw.ch david.bernhardsgruetter@zhaw.ch gernot.boiger@zhaw.ch marlon.boldrini@zhaw.ch mathias.bonmarin@zhaw.ch peter.cendula@zhaw.ch teresa.donghia@zhaw.ch jaka.dujc@zhaw.ch jonas.dunst@zhaw.ch josef.fuchs@zhaw.ch samuel.hauri@zhaw.ch thomas.hocker@zhaw.ch lorenz.holzer@zhaw.ch mojca.jazbinsek@zhaw.ch lukas.keller@zhaw.ch christoph.kirsch@zhaw.ch evelyne.knapp@zhaw.ch kevin.lapagna@zhaw.ch paoloantonio.losio@zhaw.ch philip.marmet@zhaw.ch christoph.meier@zhaw.ch martin.neukom@zhaw.ch tan.nguyen@zhaw.ch vit.orava@zhaw.ch tobias.ott@zhaw.ch omar.pecho@zhaw.ch kurt.pernstich@zhaw.ch markus.regnat@zhaw.ch nils.reinke@zhaw.ch claude.ritschard@zhaw.ch beat.ruhstaller@zhaw.ch benjamin.rutz@zhaw.ch yasser.safa@zhaw.ch guido.sartoris@zhaw.ch benjamin.schmid@zhaw.ch matthias.schmid@zhaw.ch juergen.schumacher@zhaw.ch esther.spiess@zhaw.ch moreno.torroni@zhaw.ch urs.voegeli@zhaw.ch stephan.weilenmann@zhaw.ch andreas.witzig@zhaw.ch simon.zuefle@zhaw.ch

Zürcher Fachhochschule

www.zhaw.ch

Institute of Computational Physics

A.12

Research Report 2015

Location

ICP Institute of Computational Physics Technikumstrasse 9 P.O. Box CH-8401 Winterthur www.icp.zhaw.ch Contact Andreas Witzig Phone +41 58 934 45 73 andreas.witzig@zhaw.ch Administration Esther Spiess Phone +41 58 934 73 38 esther.spiess@zhaw.ch Teresa Dâ&#x20AC;&#x2122;Onghia Phone +41 58 934 67 62 teresa.donghia@zhaw.ch

TL building

TK building

www.zhaw.ch

ZĂźrcher Fachhochschule

Zurich University of Applied Sciences

School of Engineering ICP Institute of Computational Physics Technikumstrasse 9 P.O. Box CH-8401 Winterthur Phone +41 58 934 71 71 info.engineering@zhaw.ch www.zhaw.ch/icp