Structural Parameters on the Effective Transport Properties of Carbon Cloth Gas Diffusion Layers: Random Walk...

One of the key challenges in optimizing the transfer characteristics of carbon cloth gas diffusion layers (GDLs) is accurately evaluating their effective transport properties. In this work, a stochastic reconstruction algorithm based on structural parameters was developed to generate virtual carbon cloth GDLs with varying porosities, carbon fiber diameters, and length-to-thickness ratios. A pore-scale random walk model was also developed to predict the permeability, tortuosity, and effective diffusivity of the GDLs with well-validated accuracy. The results show that higher porosity and larger carbon fiber diameters enhance the diffusion and transfer of oxygen through the GDL, and when the length-to-thickness ratio exceeds 2, the permeability stabilizes. The model developed in this study offers the advantages of low computational cost, accurate representation of the material's microstructure, and broad applicability, making it a powerful and convenient tool for predicting the transport properties of porous media.