Thermal and Electrical Analysis in a Solid Oxide Fuel Cell Stack Using a Curved Profile for the Inlet Flow Rate Along the Stacking Direction

This study analyzes the cell temperature and current density fields of a solid oxide fuel cell stack, in which the inlet flow rate along the stacking direction of the fuel is either a curved profile derived through hydraulics or a progressively decreasing profile. The results show that the temperature field was neglibibly affected by the non-uniform inlet profile of the fuel, but the current density distribution was apparently affected. The difference in current density distribution between the curved profile and the progressively decreasing profile was small in the case of an solid oxide fuel cell (SOFC) with 10 stacks, but became larger in an SOFC with 20 stacks. In the 10-stack SOFC, the difference of current density between the uniform inlet flow and the curved inlet flow was less than 3%, whereas the deviation in the curved profile was less than 12%. However, in a 20-stack SOFC, the difference of current density was over 20%, whereas the deviation in the curved profile was more than 50%. Comparing the results between the curved and the progressively decreasing inlet profile indicates that the current density difference was over 20% in the 20-stack SOFC, but below 1% in the 10-stack SOFC. Therefore, a progressively decreasing inlet profile can replace a curved profile for analyzing an SOFC stack when the number of stacks is less than 10.