燃料电池扩散层与流道中液态水传输数值模拟与协同优化

Numerical simulations for optimizing the liquid water transport in the gas diffusion layer and gas channels of a PEMFC

燃料电池流道或扩散层结构的优化是改善高电流密度下排水性能的重要措施,已有研究多集中于流道或扩散层的独立优化,缺少针对穿孔型扩散层与波浪形流道中水输运的协同优化。该文采用多松弛时间格子Boltzmann高密度比多相模型,模拟了高电流密度工况下燃料电池流道和扩散层孔隙尺度下水的输运过程,分析了扩散层中Re大小和波浪形流道角度、以及扩散层中开孔形状和位置对燃料电池水管理的影响。结果表明:对扩散层以及流道的形状进行协同优化可以更有效地提高燃料电池的排水速率;同时发现扩散层中水开始排出的时刻随着Re的增加而减小,而与波浪形流道角度、开孔形状以及位置无关。该文针对锥孔型扩散层和波浪形流道的优化对未来的燃料电池在高电流密度下的水管理优化设计具有指导意义。

The multiple-relation-time(MRT)lattice Boltzmann method with a high-density-ratio two-phase model was used to simulate liquid water transport in the gas diffusion layer(GDL)and gas channels of a high-current-density fuel cell.The results show the effects of Reynolds number,perforation shapes and locations in the GDL and the angles of the wave-like gas channels on the water transport.The results show that the GDL and the gas channels should be optimized together to improve the water removal rate.In addition,the results show that the water begins running out of the GDL at earlier times as the Reynolds number increases with the times not related to the wave-like gas channel angle or the perforation shape or location.The structural optimization of the perforated GDL and the wave-like gas channels can guide future designs of fuel cells with high current densities.