Numerical study of gas purge in polymer electrolyte membrane fuel cell

Gas purge for eliminating water from gas diffusion layer (GDL) and membrane is of great importance for polymer electrolyte membrane fuel cell (PEMFC) start-up at subfreezing temperature. A gas purge model was developed to investigate the water transport phenomenon in GDL and membrane. In simulations, hydrogen and air were used as purge streams in anode and cathode, respectively. Effects of purge conditions on gas purge were numerically studied. In addition to relative humidity, flow rate and temperature, the flow configuration of purge gases was studied for the first time. In order to improve purge performance, several purge protocols were proposed and discussed in detail with respect to purge effectiveness and energy saving.