质子交换膜燃料电池中平行流场的改进设计与多目标优化

Abstract Flow field design has a significant impact on the performance of proton exchange membrane fuel cells, especially under high current density conditions. To address the limitations of traditional parallel flow field (PAFF) in mass transfer capacity and drainage performance, this study proposes an improved cathode flow field design by introducing blocks at inlet end, middle region and outlet end, respectively. Numerical simulations revealed that the improved design of the parallel flow field with inlet block (PAIB) had the most significant performance enhancement, with a 6.1 % increase in the maximum power density and a 27.17 % reduction in the percentage of anoxic region compared to the PAFF. Furthermore, the uniformity of oxygen, current density, water content and temperature distribution were also greatly improved. To further enhance performance, an artificial neural network surrogate model coupled with non-dominated genetic algorithm II(NSGA-II) was employed to optimize block heights in each channel. Compared with the base case PAIB, the optimized design (PAIB-II) further improves the net power density by 4.6 %, reduces the percentage of oxygen-deficient region from 19.78 % to 12.19 %, and increases the oxygen homogeneity index from 0.8084 to 0.8338. Finally, a two-phase flow model based on the Volume of Fluid (VOF) method was used to evaluate drainage performance. Compared with the PAFF, the PAIB-II design has a shorter drainage time, lower liquid water volume fraction in the flow channel and lower liquid water coverage on the surface of the gas diffusion layer, demonstrating its superior water management capability.