燃料电池新型流道对气体扩散层表面水去除的影响

质子交换膜燃料电池(Proton exchange membrane fuel cell,PEMFC)中气体扩散层(Gas diffusion layer,GDL)表面液态水的有效去除和输送对PEMFC的水管理非常重要。为了有效去除GDL表面液态水,提出一种新型流道结构,采用流体体积法对流道内液态水的传输过程进行三维数值研究,研究进气速度、表面润湿性和液滴尺寸对流道内液态水的传输过程和GDL表面液态水去除的影响。研究结果表明,新型流道结构可以有效去除GDL表面液态水。随着进气速度的增大,沿流动方向的空气剪切力增大,流道内水去除速率和压降增大,GDL表面水覆盖率降低。表面润湿性对液态水传输影响显著,GDL表面润湿性增强会减缓液滴运输,流道内阻力降低,压降减小,GDL表面水覆盖率增大。管表面润湿性增强,流道内压降和GDL表面水覆盖率降低。新型流道适用于流道内大液滴的去除。当θ_GDL=150°和θ_pipe=30°时,新型流道结构有较好的GDL表面除水性能。本研究工作为流道结构提供了一种新的选择,对GDL表面液态水的去除具有一定的指导意义。

Influence of Novel Channel in Fuel Cell on Water Removal from Gas Diffusion Layer Surface

The effective removal and transportation of water on the surface of the gas diffusion layer(GDL) in the proton exchange membrane fuel cell(PEMFC) is very important for the water management of the PEMFC. In order to effectively remove water from the surface of GDL, a novel channel structure is proposed, and a three-dimensional numerical study of the transport process of water in the channel is carried out using the volume of fluid method to investigate the effects of inlet velocity, surface wettability and droplet size on the transport process of water in the channel and the removal of water from the surface of GDL. The results show that the novel channel structure can effectively remove water from the GDL surface. As the inlet velocity increases, the air shear force along the flow direction increases, the water removal rate and pressure drop in the channel increase, and the water coverage on the GDL surface decreases. Surface wettability has a significant effect on water transport. The enhanced surface wettability of GDL slows down droplet transport, reduces resistance in the channel, decreases pressure drop, and increases the surface water coverage of GDL.Enhanced pipe surface wettability decreases pressure drop and GDL surface water coverage in the channel. The novel channel is suitable for the removal of large droplets in the channel. When θ_GDL=150° and θ_pipe=30°, the novel channel structure has better GDL surface water removal performance. This research work provides a new choice for the channel structure and has certain guiding significance for the removal of water on the GDL surface.