考虑两相影响的PEMFC内部传递过程三维模拟

Three-dimensional simulation of transport processes in PEMFC considering two-phase effects

针对常规流场的质子交换膜燃料电池提出了三维非等温数学模型,在考虑水相变的情况下对电池内部传热传质和电化学反应进行了数值模拟,分析了多孔介质内水蒸气凝结和液态水分布对传递过程和电池性能的影响,并同单相模拟结果进行了对比.计算表明,水蒸气的凝结在降低多孔介质渗透性的同时,加强了反应气体向反应界面的传递;两种模型在高电流密度下阳极均缺水严重,需要更好的水管理;单相模型由于忽略了水蒸气的凝结,实际低估了电池的欧姆极化.

A three-dimensional non-isothermal mathematical model is developed for proton exchange membrane fuel cell （PEMFC） with conventional flow field. The heat and mass transfer and the electrochemical reactions are simulated considering phase change of water. The effects of water vapor condensation and liquid water distribution in porous media on transport processes and cell performance are analyzed, and the results are compared with those of singlephase model. The calculation indicates that the condensation of water vapor enhances the transport of reactant gases to reaction interfaces while decreasing the permeability of porous media. There is a lack of water in anode side at high output current densities for the two models and this requires more effective water management. And the singlephase model underestimates the actual ohmic polarization for neglecting the condensation of water vapor.