质子交换膜燃料电池阳极相对湿度对压力降影响的渐近分析

Asymptotic analysis of the effect of anode relative humidity on anode pressure drop of proton exchange membrane fuel cell

阐述了质子交换膜燃料电池(PEMFC)阳极相对湿度和阳极压力降之间的关系。根据PEMFC实际尺寸,运用气体摩尔比与局部压力比相同的原理,考虑了阳极水蒸气的摩尔流率和质子交换膜的水通率对阳极压力降的影响,建立了阳极相对湿度–压力降(RHPD)模型,并通过自定义函数将其导入软件FLUENT中进行仿真。在PEMFC工作温度为60℃、阴极相对湿度为25%、阳极相对湿度25%～75%的工况下进行试验并与仿真结果比较,进行渐进分析。结果表明:阳极压力降随着阳极相对湿度的增加而减小;当阴极和阳极相对湿度分别为25%和75%,相变阶段时间为70 s时,仿真值和试验值相对误差最小值为0.19%。

A model of anode relative humidity – pressure drop(RHPD) was established to explain the relationship between anode relative humidity and anode pressure drop, which based on the same principle of gas molar ratio and local pressure ratio, and considered the influence of the molar flow rate of anode water vapor and the water flux of the proton exchange membrane on the anode pressure drop. The RHPD model was imported into FLUENT by user– defined function(UDF) for simulation. A self-developed PEMFC test stand was carried out under working temperature of 60 ℃, cathode relative humidity of 25 %, anode relative humidity of 25 %~75%, respectively. The test results were compared with those of the simulation and the differences were analyzed. The results show that the anode pressure drop decreases with the increase of anode relative humidity, and there is only 0.19 % difference between RHPD model and the experimental data when the anode relative humidity and the cathode relative humidity is respectively 25 % and 75 % at 70 s.