Synergistic effects of “circular matrix-lattice” gas distribution zones and wavy gas-coolant channels on species distribution in proton exchange membrane fuel cells

To achieve the synergistic enhancement of mass transport, water removal, and thermal management in graphite proton exchange membrane fuel cells, this study develops a three-dimensional multiphase model integrating “circular matrix-lattice” gas distribution zones (CMLGDZ), 34 parallel wavy channels, and dual-side cooling circuits. Particular attention is given to the coupled effects of reactant flow configuration, species transport, operating pressure, high-load operation, and cooling arrangement. Counter-flow feeding of hydrogen and oxygen improves the spatial coordination among reactant concentration, product-water distribution, and membrane hydration, thereby increasing the current–density uniformity in the cathode catalyst layer by 0.004, corresponding to an improvement of approximately 0.47%. Cross-sectional analysis indicates that the CMLGDZ combined with the multiple-inlet configuration maintains stable hydrogen supply on the anode side. However, the relative deviation in cathode oxygen concentration increases along the flow direction from 23.26% to 45.86%, representing a relative increase of 97.2%; this deterioration is further intensified by liquid–water retention in low-velocity regions. Pressurized operation increases the reactant partial pressures and membrane hydration level. When the operating pressure rises from 1.0 to 2.0 atm, the average current density increases by 0.8947 A·cm −2 , corresponding to an improvement of 89.6%, although pumping-power consumption and hydrothermal non-uniformity simultaneously become more pronounced. Under high-load operating conditions, cathode oxygen depletion and localized mass-transfer polarization are further intensified. Although the net power density continues to increase, its marginal gain decreases markedly. The coolant-flow direction also restructures the coupled relationship among hotspot migration, liquid–water removal, and multiphysics-field uniformity. Specifically, aligning the cathode coolant flow with the oxygen flow direction favors instantaneous power output, whereas directing the coolant on each side along the corresponding reactant-gas flow provides a more balanced improvement in water removal, thermal uniformity, and operational stability. These findings provide a theoretical basis for the integrated design of full-plate channels, operating parameters, and cooling circuits.