In the present study, fuel cell performance on the PEMFC cathode is investigated numerically. The modeling framework is assuming that the transport process is diffusion controlled and the convection transport is neglected. Both the single phase and two-phase flows are studied. The single phase oxygen transport in the PEMFC is addressed first. The computational domain includes the gas channel, the gas diffusion layer, the catalyst later and the membrane. The predicted results are validated with the benchmark solutions of Gural et al. and good agreement is obtained. Simulations are then applied to explore the influences of the gas diffusion layer thickness, the gas diffusion layer porosity and the operating temperature on the fuel cell performance by examining the distributions of the current density and polarization curve distributions. It was found that the thin GDL thickness and high level of GDL porosity would produce better I-V polarization curve. The influence of the operating temperature is marginal within the temperature range simulated. For simplicity, the two phase computational domain is confined to the gas channel and the gas diffusion layer, and the catalyst layer is assumed to be infinitely thin. Factors affecting the fuel cell performance investigated are GDL thickness, GDL porosity and the inlet relative humidity. The percentage of the liquid water content in the GDL was found to increase with the level of the inlet humidity ratio and the thickness of the GDL and the liquid water in the GDL decreases with the increase of the GDL porosity.

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