Impact on Diffusion Parameters Computation in Gas Diffusion Layers, Considering the Land/Channel Region, Using the Lattice Boltzmann Method

Diffusion phenomena through the gas diffusion layer (GDL) at the microscale are one of the most complex physical phenomena to be described in proton exchange fuel cell (PEFC) numerical models. Predicting transport parameter behavior in GDLs is a valuable stage to propose micro-architectural designs, which can improve the efficiency and performance of fuel cells (FCs). The purpose of this paper is to propose an expression to estimate parameters involved in the diffusion process such as gas-phase tortuosity and effective diffusion coefficient when the effects of the land/channel region are considered. Three-dimensional GDL approximations are generated considering real characteristics of micro-porous layers employed in FCs. The fluid behavior through the porous media is simulated using the Lattice Boltzmann method (LBM), and the mentioned parameters are studied. The incidence of the land/channel presence over the gas-phase tortuosity is determined, and its effects over the effective diffusion are estimated.