Moisture migration in the cathode GDL of PEMFC under variable physical parameters based on a modified two-fluid model

Abstract

To predict the morphology and migration of water in the porous electrode of proton exchange membrane fuel cell (PEMFC) more accurately, a modified mathematical model of with extensions of the original two-fluid model is presented based on the heat and mass transfer model of unsaturated porous media. The model integrated the mechanisms of the capillary effect, pressure, diffusion, and phase-to-phase interaction, and was applied to the numerical study of the single-fluid channel cell herein. The results show that the interaction between the gas and liquid is dominated by the drag force caused by relative motion, which highly depends on the position and local water saturation. What's more, a higher porosity facilitates the discharge of liquid and gaseous water in the GDL, while for the permeability, there exists a local optimum value which leads to a lowest liquid saturation in the GDL and helps to avoid the flooding phenomenon.