Abstract: The air-breathing proton exchange membrane fuel cells (PEMFCs) are one of the most competitive candidates for future portable-power applications. To predict the performance of air-breathing PEMFCs and promote its commercialization, a three-dimensional mathematical model was developed,including full governing equations for fluid dynamics, electrode kinetics, and water transport in membrane. The model was numerically solved with commercial CFD tool STAR-CD and user-defined subroutine in FORTRAN code using the finite-difference technique. According to the numerical results, the experiment system was designed. The performance of an air-breathing PEMFC and temperature distribution on the surface of diffusion layer was tested. The calculated cell performance curve was in good agreement with experimental results.It was demonstrated that the oxygen mass transfer rate by natural convection played a major role in cell performance and the interaction of velocity, temperature, current density, water concentration. The model could be used as a computer-aided design tool for an air-breathing PEMFC to obtain better cell performance.

摘要： 在空气自然对流式燃料电池内部，速度、温度、组分浓度及电流分布特性有着极强的耦合作用.氧气质量传输限制引起的浓度过电位是这种燃料电池的主要性能损失.从自然对流、传热传质的角度，建立了三维数学模型.利用三维流体动力学软件和用户建立的子程序，对自然对流下Navier-Stokes 方程，能量方程，电化学动力学方程以及组分、水的传输方程进行了数值求解.通过分析数值计算的结果，结合自然对流的特性，设计了实验系统.对温度分布和电池性能进行了测试.对空气湿度对电池性能的影响进行了分析.数值计算结果与实验结果很好地吻合.模型的建立，对于认识空气自然对流式质子交换膜燃料电池内部的耦合传输现象有极大的意义，可以作为质子交换膜燃料电池的计算机辅助优化设计工具.