Performance predictions in solid oxide fuel cells

The results of numerical calculations performed for planar solid oxide fuel cells are presented. Two different approaches are developed: (i) A detail numerical method and (ii) a presumed flow method. In the first approach, a commercial computational fluid dynamics code is employed, and user-defined-functions are developed to account for electro-chemical considerations. In the second approach, where the momentum equations do not require to be solved, an in-house code is developed and used to perform calculations. In both cases the following coupled physicochemical phenomena are modelled; heat and mass transfer, electrochemistry and electric potential. The polarisation curve is generally accepted as an important performance measure of the fuel cell. Performance predictions for this characteristic made by the two different approaches are compared. Results show voltage losses due activation, Ohmic resistance, and mass transfer in a typical solid oxide fuel cell, over a range of current density values. The results for the detailed numerical method are discussed in some detail with regard to the influence of different parameters on the overall performance of the device.