Numerical simulation of the effect of microstructure on liquid water transport in GDL-gas channel in fuel cell

The optimization of the water management of the gas diffusion layer (GDL), the accurate control of its interface’s two-phase flow characteristics, the prevention of excessive liquid accumulation, and the enhancement of mass transfer efficiency are of crucial importance for the lifespan and performance of fuel cells. The study employs a numerical simulation method to investigate the impact of perforation on water transport characteristics inside the gas diffusion layer (GDL) in a fuel cell. Different perforation diameters, depths, spacing, and wetting properties were analyzed and compared with an unperforated GDL. Results show perforation significantly enhances liquid water distribution within the GDL and decreases local water saturation. A perforation diameter of D = 75 µm improves the GDL’s internal water transport performance. A fully penetrating perforation with a diameter of 200 microns has the strongest effect, which can almost eliminate the liquid water in the GDL except for that in the perforation. A spacing of L = 225 µm significantly improves the GDL’s liquid water distribution, resulting in more uniformity. The study of wettability around perforations revealed a hydrophilic area further reduces local water saturation. These findings are important for optimizing fuel cell design and provide theoretical guidance for design and optimization. Future studies can focus on optimizing perforation shape and size to improve fuel cell efficiency, stability, and reliability.