Water Transport in GDL Microstructures of Nonuniform Fiber Diameter Arrangement

Abstract

In proton exchange membrane fuel cells (PEMFCs), the gas diffusion layer (GDL) plays an important role in the transport of reactants, water, heat, and electrons. Microstructure manipulation of porous media via a nonuniform fiber diameter arrangement could potentially be used to improve water transport behavior in GDLs. A numerical modeling approach is used to simulate GDL microstructures with uniform and nonuniform fiber diameters. The reconstructed porous microstructures’ water saturation and porosity are compared. The simulations of three-dimensional (3D) two-phase flow volume of fluid (VOF) models were completed on the OpenFOAM platform using the finite volume method (FVM). Simulations demonstrate that by adopting a nonuniform microstructural fiber diameter design, both porosity and water transport behaviors can be altered. As a result of the nonuniform fibrous arrangement, the ability to improve GDL performance by controlling water transport and porosity is possible. The results indicate that by manipulating the GDL microstructure, additional water pathways can be created, resulting in slightly increased water saturation. We propose that water transport can be improved by microstructural manipulation of the GDL, specifically by optimizing the arrangement and position of nonuniform fibers.