Investigation of mass transfer and reaction characteristics in three-dimensional fully morphological channel-ridge type gas distribution zones for proton exchange membrane fuel cells

A well-designed gas distribution zone (GDZ) ensures uniform distribution of reactant gases over the active area, improves the output performance of the cell, and enhances the water and thermal management in the proton exchange membrane fuel cell (PEMFC), thereby ensuring efficient and stable operation of large scale PEMFCs. This study focuses on the design of a forced-flow type GDZ. A three–dimensional, multiphase, non-isothermal numerical model was established. Using this model, the effects of the GDZ ridge-to-channel number ratio, secondary split-flow, and oblique channel ridge length on cell performance were systematically investigated. The results demonstrate that, in comparison to the conventional empty-chamber gas distribution zone, a GDZ with a ridge-to-channel number ratio of 1:1 improves the uniformity of oxygen distribution in the middle plane of the gas diffusion layer by 3.401%. This enhancement concurrently suppresses concentration polarization effectively, thereby contributing to a 2.29% increase in the peak power density of the PEMFC. Further research revealed that secondary flow channel ridges only yielded suboptimal performance due to mass transfer limitation and liquid water accumulation. ... mehrAdopting moderately long oblique ridges is crucial, as it strikes a balance between reactant gas distribution, pressure drop and water management.