Simultaneous Simulation of Gas Diffusion Layer and Air Channel in a PEM Fuel Cell: Pore-Scale Modeling of Water Flooding

In this study, Lattice Boltzmann method (LBM) is used to investigate liquid water transport in a carbon paper gas diffusion layer (GDL) and gas channel (GC) of polymer electrolyte membrane fuel cells (PEMFC). The carbon paper GDL is reconstructed using the stochastic method. This work is done in a microscopic porous structure and behavior of liquid water clusters from catalyst layer / GDL interface to gas channel is studied. In this study, the dynamic behavior of liquid water during removal from gas diffusion layer (GDL) of a PEMFC electrode is simulated using LBM. The effects of GDL wettability on the removal process and liquid water distribution are investigated. In addition, liquid water dynamic behaviors and liquid water saturation within the GDL in two case of steady and transient are explored. This study focuses on the effects of surface wettability on the number of effective clusters, merging of clusters, and the required time for reaching the steady-state water distribution. The simulation results show that by increasing the contact angle of fibers in GDL, the required time to obtain a steady-state water distribution is reduced. Therefore, if the solid surface becomes more hydrophobic, water management will be improved in the gas diffusion layer.