基于三维非等温多相模型的质子交换膜燃料电池局部传质机理

Local Mass Transfer Mechanism in Proton Exchange Membrane Fuel Cell Using 3D Nonisothermal Multiphase Model

为使质子交换膜燃料电池(PEMFC)内部的电极反应物和电极产物有一个更加稳定与均衡的分布,在燃料电池传统阴极蛇形流道的基础上,对其U形转弯入口及出口处进行渐缩渐扩处理,使流道U形转弯处侧壁形成一定角度的坡面,并建立了缩放坡面流道的单电池三维数值模型。对比研究了不同几何参数对流道内液态水动力学行为、排水效率、反应气体质量分数、电池最大功率密度的影响,结果表明坡面结构在一定程度上引导了液滴的流动路径,使流道底面的气体扩散层(GDL)附近气流扰动增强,氧质量分数和电流密度分布更加均匀,最大功率密度得到了明显提高,整体上提高了PEMFC内部的传质能力。

To make the electrode reactants and products in the proton exchange membrane fuel electricity(PEMFC)more stable and evenly distributed,in this study,based on the traditional cathode serpentine flow channel of fuel cells,the inlet and outlet of the U-turn are gradually tapered and expanded,and the side wall of which was made to form a certain slope angle.A three-dimensional numerical model of a single cell with a tapered and expanded slope flow channel was established.The effects of different geometrical parameters on the kinetic behavior of liquid water in the flow channel,drainage efficiency,reaction gas mass fraction,and maximum power density of the cell were studied comparatively.The results showed that the slope structure guided the flow path of droplets,and the airflow perturbation near the bottom surface Gas Diffusion Layer(GDL)of the flow channel was enhanced.The oxygen mass fraction and current density were shown to be more uniformly distributed,and the maximum power density and the overall mass transfer capacity inside the PEMFC were improved.