Flow characteristics and optimization of the orientated gas flow channels of proton exchange membrane fuel cells

Orientated-type gas flow channels are beneficial for the enhancement of Proton Exchange Membrane Fuel Cells (PEMFC) performance; however, higher flow losses are incurred as well. In this study, the flow characteristicss of the orientated gas flow channel are studied numerically; and the geometries of baffles are optimized using a Genetic Algorithm to minimize their flow losses. The results show that as the middle baffle length (L1) increases, the high-velocity zone expands, which leads to higher friction losses and pressure drops. Moreover, increasing the sloped leeward side baffle length (L2) reduces the vortices size on the leeward side, and increasing the inclination angle of the leeward side can mitigate the boundary layer separation and vortices formation. For lower baffle heights (R = H/4 and R = H/2), an increase in the mid-section length leads to a significant reduction in flow losses, indicated by pressure drop. However, for high baffle heights (R = 3H/4), the optimal L2 is insensitive to the variation of L1, indicating that the baffle height for high baffles dominates the flow resistance of channels. The pressure drop between the inlet and outlet of the optimized channel can be reduced by 4.8% compared to that of the original geometry.