Analyzing and optimizing cathode gas distribution uniformity in proton exchange membrane fuel cell stacks based on two-phase flow network model

Uneven distribution of reactive gases in proton exchange membrane fuel cell stacks deteriorates the material state and performance of individual cells, leading to a “barrel effect” that significantly reduces the stack lifespan and safety. In this work, a flow network model incorporating two-phase flow effects is developed to comprehensively assess the impact of two-phase flow effects, flow field types, and flow resistance types on the uniformity of cathode gas flow distribution within the stack. Results show that at the current density of 1.2 A cm⁻², ignoring two-phase flow leads to the flow uniformity index being overestimated by 429.52 %. Stacks using flow fields with greater flow resistance achieve more uniform gas flow distribution, and compared to increasing frictional resistance, enhancing flow distribution through increases local resistance requires less additional pump work. Furthermore, the differential flow field configuration strategy proposed in this study significantly improves the uniformity of flow distribution, with the stack inlet and outlet pressure drop being 21.97 % lower than that achieved by increasing local flow resistance alone. This study not only opens new perspectives for research into optimizing design of cathode flow fields but also provides potential solutions to the problem of uneven flow distribution in stacks.