CFD Simulation of Two-Phase Flow Patterns in the Gas Channel of a Proton Exchange Membrane Fuel Cell

Water management plays a critical role in the operation of a proton exchange membrane fuel cell (PEMFC). The liquid water emerging from the gas diffusion layer (GDL) in the gas flow channel of a PEMFC gives rise to liquid-phase flow patterns, which affect the fuel cell performance. The role of the surface properties of the GDL was investigated through numerical analysis by varying the hydrophobic characteristic of the GDL. The effect of different channel geometries was also taken into account by considering a classical rectangular channel and a tapered one. Tapering the gas flow channel increases the gas velocity and thus the water removal, but it also raises the pressure drop. The water removal rate is enhanced by an increase in the hydrophobic properties of the wall