Gas and water transport in the gas diffusion layer of proton exchange membrane fuel cell

Abstract

The main content of this study is the water and gas transport processes within the gas diffusion layer (GDL) of proton exchange membrane fuel cells (PEMFCs). During the research, two key issues were focused on: 1. The distribution characteristics of water and gas within the GDL. 2. The influence of permeability on the transport process. Since it is difficult to directly observe the water and gas transport within the GDL during the operation of the fuel cell using conventional experimental methods, this study employs the numerical simulation approach using the COMSOL Multiphysics software for investigation. The research process includes the physical field setting based on the Darcy law of two-phase flow, geometric modeling, parameter and boundary condition setting, and parametric scanning with permeability as the variable. During the simulation process, the transport behaviors of oxygen, water vapor, and liquid water in the GDL were mainly analyzed. According to the simulation results, it is known that 1) the oxygen concentration gradually decreases along the direction from the inlet to the catalyst layer, 2) the concentration of water vapor is higher near the catalyst layer, 3) there is a significant accumulation of liquid water in local areas, 4) the regions with higher liquid water content will hinder gas transport, and 5) a higher permeability is conducive to the gas transport process