Numerical Simulation of Local Entropy Generation of Oxygen Transport in Cathode Diffusion Media of PEFC

The oxygen transport in cathode electrodes of polymer electrolyte fuel cells (PEFCs) is a key process for determining their power generation performance. To identify the factors affecting its transport loss, this study introduced the analysis of local entropy generation into the conventional two-phase flow simulation in the cathode gas diffusion layer (GDL) of a PEFC and estimated the distribution of the entropy production rate due to oxygen diffusion. The effect of land-channel geometry on its entropy generation in the GDL was also evaluated. The results revealed that the entropy generation of oxygen diffusion becomes remarkably high under the boundary between the channel and land that causes its large concentration gradient. It was also found that the entropy generation due to oxygen diffusion in the GDL increases with an increase in the water accumulation during the operation.