Two-Phase flow study in the 3D fine-mesh flow field and gas diffusion layer of proton exchange membrane fuel cells

Abstract

The two-phase flow transport mechanisms in the 3D flow field and gas diffusion layer (GDL) of proton exchange membrane fuel cells are not fully understood. In this study, the GDL structure was reconstructed using micro-CT technology, and the two-phase flow behavior in the 3D fine-mesh flow field (FMFF) and GDL was simulated and analyzed using the phase-field lattice Boltzmann method. The results show that the FMFF significantly enhances gas convection in both the flow field and GDL, reduces liquid water saturation, increases the pore area for gas transport at the interface between the two, and makes the distribution of gas and liquid in the GDL more uniform. Liquid water tends to accumulate above the air stagnation zone and below the concave baffle. Additionally, increasing the gas flow rate reduces the liquid water volume transported to the upper side of the flow field plate. Hydrophilic flow field plates facilitate liquid water transport above the plate but tend to accumulate liquid water in the flow field; conversely, hydrophobic flow field plates exhibit the opposite behavior. Comprehensive analysis reveals that flow field plates with a contact angle between 90° and 110° offer the most balanced performance.