SOFC Modeling in Femlab
Ladda ner
Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Engineering Physics (300 hp)
Publicerad
2003
Författare
Nordelöf, Anders
Salsing, Christofer
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This report describes a graduate thesis project for the Master of Science diploma from the Engineering Physics program at Chalmers University of Technology. It has been performed at Volvo Technology Corporation with the primary aim to model a given Solid Oxide Fuel Cell design, the Rutquist cell, in Femlab. The model is intended to provide information on current-voltage characteristics, power development and the temperature profile, both during startup and operation. The secondary purpose was to evaluate the suitability of Femlab for this kind of task. The project was initiated with a bibliographic research, which gave several theories and parameters useful for modeling the different processes in the SOFC design. These models were then implemented in Femlab. Two separate modes were created where the startup and the operation of the cell respectively, were simulated. The cell was assumed to be a part of a larger system and receive hot gases from a fuel reformer. The heating in the startup process was achieved by letting warm gas, 1073 K, enter the electrodes via the gas channels. The chemical reactions were assumed to begin when all parts of the structure had reached 1023 K. The calculations showed that the heating to this temperature takes about one minute, and that most of the heat exchange takes place in the electrodes. The resulting temperature profiles from the operation mode model demonstrate that the temperature is in the same range as other SOFC structures and that the design is very compact. The dimensions of a cubic stack developing 10 kW at maximum power would be less than one cubic decimeter. The computational software Femlab has advantages, but also several shortcomings. Among the advantages are the flexibility in the module based system and the short learning period needed for solving simple problems. The weaknesses include the necessity of good knowledge of numerical solution methods, since many settings have to be adjusted when the models become more complex; especially the error report system is poor and occasionally even missing. The report also presents the theory of the physical and chemical processes ceramic fuel cells. Suggestions for improvements and the effects of the delimitations and approximations used in the modeling work are discussed. Finally, recommendations for future work are put forward.
Beskrivning
Ämne/nyckelord
Grundläggande vetenskaper , Energi , Keramteknik , Hållbar utveckling , Miljöteknik , Teknisk fysik , Materialfysik med ytfysik , Materialvetenskap , Basic Sciences , Energy , Ceramics , Sustainable Development , Environmental engineering , Engineering physics , Material physics with surface physics , Materials Science