Cell-to-Cell Variations With Increasing SOFC Stack Size

This numerical study considers the influence of stack size on cell-to-cell performance variations within a stack of planar solid oxide fuel cells. In order to model large stacks (>10 cells) a pseudo 2-D scheme was implemented using the parallel technique of domain decomposition and was solved on a Beowulf cluster. Results were obtained for stacks of 5, 10, and 20 cells. The results indicate that although significant variations in temperature were observed the voltage variations were practically negligible for cases with uniform flow distribution. Non-uniform fuel flow distribution resulted in more significant cell voltage variations. With the assumption of adiabatic boundary conditions, increasing stack size resulted in slightly lower average cell temperatures but increased outlet temperature of the fuel and air channel in the top cell.