Investigation of convective transport in the gas diffusion layer used in polymer electrolyte fuel cells

Recent experimental data on a fuel-cell-like system revealed insights into the fluid flow in both free and porous media. A computational model is used to investigate the momentum and species transport in such a system, solved using the finite element method. The model consists of a stationary, isothermal, diluted species transport in free and porous media flow. The momentum transport is treated using different formulations, namely, Stokes-Darcy, Darcy-Brinkman, and hybrid Stokes-Brinkman formulations. The species transport is given by the advection equation for a reactant diluted in air. The formulations are compared to each other and to the available experimental data, where it is concluded that the Darcy-Brinkman formulation reproduces the data appropriately. The validated model is used to investigate the contribution of convection in reactant transport in porous media of fuel cells. Convective transport provides a major contribution to reactant distribution in the so-called diffusion media. For a serpentine channel and flow with Re = 260-590, convection accounts for 29-58% of total reactant transport to the catalyst layer.