In this study, a proton exchange membrane (PEM) fuel cell stack composed of five cells in series is numerically investigated to study the impact of the nonuniform reactant flow rate on the performance of the stack. A comparison of the water concentration, temperature, reaction heat source, and current density of change rule of two groups of fuel cell stacks with uniform and nonuniform reactant flow rate reveals the performance degradation mechanism caused by nonuniform reactant flow. The results indicate that while operating under low-voltage conditions, the nonuniform reactant flow rate will cause the accumulation of excess liquid water near the PEM that is near the cathode exhaust outlet, and the local area reacts strongly on the catalyst, whereas the local area reacts slowly. When the average voltage of the stack is 0.55 V, the current density under the nonuniform reactant flow rate condition is 12.9% lower than that of the uniform reactant flow rate condition. In the case of uniform and nonuniform reactant flow rate at low current densities, the performance difference is not evident, but it is expected to be pronounced with the increase in current density. The simulation results are compared with the experimental data reported in the literature through a polarization curve, and they turn out to be well correlated with the experimental results.

在这项研究中，数值研究了由五个串联的电池组成的质子交换膜（PEM）燃料电池堆，以研究不均匀反应物流速对电池堆性能的影响。比较反应物流量均匀和不均匀的两组燃料电池堆的水浓度，温度，反应热源和电流密度变化规律，揭示了反应物流动不均匀引起的性能下降机理。结果表明，在低压条件下运行时，反应物流量不均匀会导致多余的液态水在靠近阴极排气口的PEM附近积聚，并且局部区域在催化剂上发生强烈反应，而局部区域反应缓慢。当堆叠的平均电压为0.55 V时，非均匀反应物流量条件下的电流密度比均匀反应物流量条件下的电流密度低12.9％。在低电流密度下反应物流量均匀和不均匀的情况下，性能差异不明显，但是随着电流密度的增加，这种差异有望得到明显体现。通过极化曲线将仿真结果与文献中报道的实验数据进行比较，结果证明它们与实验结果具有很好的相关性。