Numerical modeling and performance prediction of water transport for PEM fuel cell.

Abstract A 2D PEMFC model has been built to simulate the current density distribution and liquid water distribution in cathode. In this simulation, the air mass flow rate, relative humidity of the air and cell voltage are considered as the input parameters into the model, the diagram of current density and liquid water distribution in cathode are shown according to the simulation result and compared to each other. The result indicates that the liquid water distribution has a strong positive relation to the current density, where water drops diffuse mainly by the pressure difference (capillary force) in the porous media (the porous media coefficient εp is very low), where the shear force of the air can hardly drive the water drops due to the high friction force of the porous media. In the thin porous media (the porous media coefficient εp is relatively high), the purge effect of the air flow can be enhanced, decreasing the flooding areas in the cathode. Due to the purge effect of the air flow, the outlet of the cathode is the critical areas, where the flooding is most likely to happen. The steep trough at the current density distribution may mean the local flooding, which blocks the oxygen and weaken the chemical reaction. [ABSTRACT FROM AUTHOR]