HT-PEM燃料电池组合流场的性能模拟

Performance simulation of HT-PEM fuel cells with the different combination of flow field

为了研究流场结构对HT-PEM燃料电池性能的影响,运用多物理场直接耦合分析软件(COMSOL Multiphysics),对由两种流道组合而成的4种流场(两种单一流场与两种混合流场)的HT-PEM燃料电池进行了数值模拟。在相同的操作条件下,得到了4种组合流场的极化曲线、阴极氧气浓度变化及阴极流道中心压力变化情况。对模拟结果进行分析和比较得出:阴极氧气浓度和阴极流道中心压力均沿着气体流动方向逐渐降低,其变化主要发生在流道的拐角处及渐变处;综合考虑输出电流密度、气体传质及气体在电极各处分配的均匀性等因素,蛇形渐变流场的整体性能最好,阳极普通蛇形流场/阴极蛇形渐变流场组成的混合流场其次,普通蛇形流场再次,阳极蛇形渐变流场/阴极普通蛇形流场组成的混合流场最差。模拟结果对HT-PEM燃料电池结构的优化和设计具有重要的指导意义。

In order to study the influence of flow field structure on HT-PEM fuel cell, HT-PEM fuel cells with different combination of flow field （two kinds of single flow field and two kinds of mixed flow field） were simulated by using more physical fields direct coupling analysis software COMSOL Multiphysics. At the same operating conditions, simulated the polarization plot, oxygen concentration variation and pressure variation of flow field center in cathode for the four combinations, then by analyzing and comparing the simulation results we got that both the oxygen concentration and pressure of the flow field center in cathode reduced gradually along the direction of gas flow, and the changes mainly occurs at the corner and the gradient of the flow field. Considering the output current density, mass transfer and the distribution uniformity of gas throughout the electrode ect, the output of serpentine flow field gradient compared with the best performance, secondly, the mixed flow field which was combined by ordinary serpentine flow field in anode and serpentine flow field gradient in cathode, thirdly, the ordinary serpentine flow field and the mixed flow field which was combined by serpentine flow field gradient in anode and ordinary serpentine flow field in cathode is the worst. The simulation results have an important guiding significance on the optimization of the structure and design of HT-PEM fuel cells.