质子交换膜燃料电池（Proton Exchange Membrane Fuel Cell，PEMFC）流道结构优化能提高反应气体质量传输效率和电流密度，是改善PEMFC输出性能的有效方法。建立PEMFC单直流道几何模型，通过在流道内添加梯形挡板研究了挡板倾角对反应气体传输特性的影响。结果表明，在流道内添加挡板，可明显提高流道内反应气体流速并促进反应气体由流道向扩散层的质量传输；增大对称和非对称梯形挡板的前、后倾角，可有效增大挡板下方O2质量分数，提高气体扩散层中反应气体通量，强化反应气体质量传输；与对称梯形挡板相比，前倾角75°、后倾角60°或前倾角60°、后倾角75°的非对称梯形挡板强化反应气体质量传输的效果更佳；PEMFC扩散层与催化层中的O2摩尔分数随挡板数量增加而显著提高，且在挡板对应区域出现反应气体浓度波峰；PEMFC输出性能随流道内挡板数量增加而提升。流道内添加11个前倾角60°、后倾角75°的非对称梯形挡板时PEMFC峰值功率密度为0.435 W/cm2，比无挡板时提高6.6%。此外，工作电压U=0.1 V时，无挡板流道的电流密度为1.57 A/cm2，挡板数量为11时,电流密度为1.80 A/cm2，提升约14.6%，研究结果为后续PEMFC流场优化提供了理论和技术借鉴。

The optimization of the flow channel structure of proton exchange membrane fuel cell (PEMFC) can improve the mass transfer efficiency of reaction gas and increase the current density, which is an effective method to improve the output performance of PEMFC. First, the geometric model of a single straight channel of PEMFC was established, and the influences of baffle inclinations on the transmission characteristics of reaction gas were studied by adding trapezoidal baffle in the flow channel. The results show that adding baffles in the flow channel can significantly increase the flow rate of reaction gas in the flow channel and promote the mass transmission of reaction gas from the flow channel to the diffusion layer. Increasing the front and rear of inclination angle of the symmetrical and asymmetric trapezoidal baffle can effectively increase the O2 mass fraction under the baffles,  improve the flux of reaction gas in the gas diffusion layer, and strengthen the mass transfer of reactive gases. Compared with the symmetric trapezoidal baffle, the asymmetric trapezoidal baffle with 75° front and 60° back or 60° front and 75° back angles has a better effect on enhancing the mass transfer of the reactant gas. The O2 concentration in the diffusion layer and catalytic layer of PEMFC increases significantly with the increase of the number of baffles, and the peak of reaction gas mole fraction appears in the corresponding area of the baffles. The output performance of PEMFC increases with the number of baffles in the flow channel. The peak power density of PEMFC is 0.435 W/cm2 when 11 asymmetric trapezoidal baffles with 60° front and 75° back inclination are added to the flow channel, which is 6.6% higher than that without baffles. In addition, when the working voltage U=0.1 V, the current density of the flow channel without baffle is 1.57 A/cm2, and when the number of baffles in the flow channel is 11, the current density is 1.80 A/cm2, which increases by about 14.6 %. The research results provide a theoretical basis and technical reserve for the subsequent PEMFC flow field optimization.

0 引言

1 PEMFC模型建立

   1.1 工作原理

   1.2 几何模型

   1.3 模型假设

   1.4 控制方程

   1.5 边界条件

   1.6 计算方案

2 PEMFC模型验证

   2.1 仿真验证

   2.2 试验验证

3 结果与分析

   3.1 对称梯形挡板对PEMFC性能的影响

   3.2 非对称梯形挡板对PEMFC性能的影响

   3.3 挡板数量对PEMFC性能的影响

4 结论