Optimization of proton exchange membrane fuel cell stack manifold inlet geometry using velocity-assisted gray wolf optimization algorithm

The manifold structure in high power PEMFC stacks has a great influence on the airflow distribution, which directly affects the performance and temperature uniformity of the stack. Existing manifold structures tend to have high-intensity vortices in the front region of the manifold, which form a gas recirculation zone and prevent the gas from uniformly entering the single-cell. The aim of this study is to investigate the influence law of the geometry of the inlet region of the stack on the flow field distribution characteristics and fluid distribution uniformity within the stack. The diffuse inlet structure is designed and the multidimensional parameters of its geometry are optimized using VAGWOA. The results confirm that the diffuse inlet structure affects the vortex generation and increases the mass flow rate of single-cell near the stack inlet. When the CRR of the optimized structure is 0.2029 and the inlet diameter is 29.1507 mm, the CV of mass flow rate in the stack decreases by 92.76 %, the pressure inhomogeneity coefficient decreases by 44.27 %, and the velocity inhomogeneity coefficient decreases by 89.92 %. The optimized manifold effectively mitigates the adverse effects induced by the double symmetric vortex structure at the front end, thereby significantly improving gas distribution uniformity.