质子交换膜燃料电池两维、两相流动模型

A Two-dimensional, Two-phase Flow PEM Fuel Cell Model

提出了考虑电池内部两相流动的质子交换膜燃料电池数学模型,模拟了阳极、阴极两侧的流道和扩散层中同时发生两相流动时电池内部的各种传递特性,并用实验数据验证了该模型的准确性。模拟结果显示,当电池阴极扩散层中有液态水存在时会大大降低膜中的局部电流密度;质子交换膜中水的净通量方向可正、可负,因此电池的增湿策略应根据不同的运行工况而不断变化。

A two-dimensional numerical model was developed to simulate proton exchange membrane fuel cell. The model takes into accounts simultaneously the two-phase flow transports in both anode and cathode gas channels and gas diffusion layers, electrochemical kinetics in catalyst layers, current density distribution and water content distribution in the membrane and net water flux through the membrane. The model was validated against experimental data with good agreement. The modeling results show that the net water flux can flow either from the anode side to the cathode side or from the opposite direction through the membrane, as a result, anode water concentration fraction would decrease or increase according to different current densities. The appearance of liquid water at the cathode gas diffusion layer would sharply decrease the local current density, and the humidification strategies should always be changed with the changing working conditions of a PEM fuel cell so as to keep the proton exchange membrane fully saturated and to prevent the cathode gas diffuser being flooded.