The effect of operating parameters on water transport in PEM fuel cells

Water content in the membrane and the presence of liquid water in the catalyst layers (CL) and the gas diffusion layers (GDL) play a very important role in the performance of a PEM fuel cell. To study water transport in a PEM fuel cell, a two-phase flow mathematical model is developed. This model couples the continuity equation, momentum conservative equation, species conservative equation, and water transport equation in the membrane. The modeling results of fuel cell performances agree well with measured experimental results. Then this model is used to simulate water transport and current density distribution in the cathode of a PEM fuel cell. The effects of operating pressure, cell temperature, and humidification temperatures on the net water transfer through the membrane, liquid water saturation, and current density distribution are studied.