Mass Transfer and Power Loss of Proton Exchange Membrane Fuel Cells with Blocked Flow Channels

Abstract

Blocked flow channel can enhance the reactants transfer process and improve the output performance of proton exchange membrane fuel cells. In waved-like blocked flow channels, the flow resistance at the windward side can be reduced because of the streamline shape design. However, the vortexes, which account for the power loss, can be formed at the leeward sides. In this work, a two-dimensional, two-phase, non-isothermal and steady state model is developed, and flow channels with different wave-like blocks are designed to investigate the effects of windward sides and leeward side on output performance of proton exchange membrane fuel cells. Simulation results show that: when the heights and weights of wave-like blocks are both fixed, longer leeward side of blocks facilitate to reduce the vortexes forming and decrease the pumping powers, in the meantime, the net powers and the efficiency are improved. However, when the leeward sides of blocks are shortened and windward sides are lengthened, vortexes forming in flow channels are strengthened and pumping powers are improved, and the net powers are reduced. Moreover, when the leeward side is prolonged, the liquid water in flow channels can be removed more easily.