Detailed simulation parameters are described and emphasis is placed on establishing convergence criteria which are essential for producing consistent results. In this thesis three different areas of experimental characterization techniques was investigated, they include: The reason for this is that fuel cells currently suffer from too high production prices and too short life times, in relation to market requirements.
Methods for creating computer aided design CAD models of fuel cells are discussed.
It has been shown that these tools are Fuel cell modeling thesis means for obtaining very detailed data of the manifold flow. Additional,a focus on the dynamics and system control of the RMFC have been studied, which have also been a big part of the motivation for this work.
PEMFCs have several important limitations which must be overcome before commercial viability can be achieved. However, utilizing the excess hydrogen in the system complicates the RMFC system as the amount of hydrogen can vary depending on the fuel methanol supply, fuel cell load and the reformer gas composition.
The focus of this thesis has been to develop experimental techniques, that can aid in the development of making fuel cells cheaper and more durable. The method does however hold the potential to be used as a sensor in fuel cell control systems and to be transferred into a current density measurement tool.
The measurement method was furthermore transferred onto a Labview platform, which signiffcantly improves the exibility and lowers the cost of using this method. In the area of stack flow and pressure distribution, the techniques of CFD, PIV and differential pressure measurements have been adopted to study flow phenomenons in the cathode manifold, with special emphasis on the manifold inlet conguration.
The HT-PEM fuel cell operates at elevated temperatures above oC and therefore uses phosphoric acid as a proton conductor. Some of the methods used are well established techniques, such as AC impedance spectroscopy, and some are novel techniques developed in this project, such as the in situ temperature measurement methods.
The fuel is reformed with a steam reforming to a hydrogen rich gas, however with additional formation of Carbon Monoxide and Carbon Dioxide. Fuel cells are a key technology needed to cope with the climate changes of the future. However, compressed hydrogen is stored in the range of bar, which can be expensive to compress.
Moreover, the tools complement each other well, as high quality validation data can be obtained from PIV measurements to verify CFD models.
This technique is expected to bea very important future tool, used both for material characterization, celldiagnostic, system optimization and as a control input parameter in fuel cell systems. This PhD study has therefore been involved in investigating the gas composition of the reformer and the affects to the HT-PEM fuel cell.
It is the hope that the contribution of this thesis can aid in bringing fuel cells faster to the market.
Computer modeling can also help improve fundamental understanding of the mechanisms and reactions that take place within the fuel cell.
The overall purpose of the experiments conducted in this project, is to provide fundamental knowledge of the transport and electrochemical processes of PEM fuel cells and to provide methods for obtaining high quality data for PEM fuel cell simulation model validation.
High quality computer modeling and simulation of fuel cells can help speed up the discovery of optimized fuel cell components. Two novel methods for measuring the in situ temperature was developed in this project. A study of iteration sensitivity of the simulation at low and high current densities is performed which demonstrates the variance in the rate of convergence and the absolute difference between solution values derived at low numbers of iterations and high numbers of iterations.
Fluid Mechanics and Combustion Abstract Many fuel cells systems today are operated with compressed hydrogen which has great benefits because of the purity of the hydrogen and the relatively simple storage of the fuel. Active areas of research into making them commercially viable include reducing the cost, size and weight of fuel cells while also increasing their durability and performance.
Details Fuel cells are strong candidates to become the power sources of the 21th century. Details Many fuel cells systems today are operated with compressed hydrogen which has great benefits because of the purity of the hydrogen and the relatively simple storage of the fuel.
Fluid Mechanics and Combustion Abstract Fuel cells are strong candidates to become the power sources of the 21th century. A mesh sensitivity study of the catalyst and membrane layers is presented showing the importance of adhering to strictly defined convergence criteria.
Stack flow distribution tools, AC impedance spectroscopy and in situ temperature measurement techniques.modeling and control of a pem fuel cell system a thesis submitted to the graduate school of natural and applied sciences of middle east technical university.
3-DIMENSIONAL COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELL USING DIFFERENT FUELS. by. SACHIN LAXMAN PUTHRAN A THESIS. Presented to the Faculty of the Graduate School of the. THESIS Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE In Transportation Technology & Policy I would like to thank the staff and the researchers of the Fuel Cell Vehicle Modeling Program, UC Davis without whose help this project would not have taken place.
Specifically, I am grateful to Dr. Robert.
Power Distribution System Modeling and Simulation of an Alternative Energy Testbed Vehicle A thesis presented to the faculty of the Russ College of Engineering and. Improving and Understanding Direct Methanol Fuel Cell (DMFC) Performance By Alexandre Hacquard A Thesis submitted to the faculty of.
ONE DIMENSIONAL MODELING OF PLANAR SOLID OXIDE FUEL CELL A thesis presented to The faculty of the Fritz J. and Dolores .Download