Modeling And Optimization Of Gas Field In PEM Fuel Cell System For Vehicle Application

Proton Exchange Membrane Fuel Cell (PEMFC) has become one of the hotspot for its high-energy efficiency, low noise, pollution-free characteristics, simplicity in design and operation, low operation temperature and safety. The gas field is of significant importance for the PEMFC stack. In order to keep the fuel cells working well and to do a good water management, it is necessary to design the gas field of the PEMFC stack, so as to make sure the hydrogen and air could be sent to all the fuel cells homologous and with a certain velocity.The basic theory of fuel cell is described firstly. A three dimension mathematical model is described to model the working process of PEMFC, it accounts simultaneously for the fluid flow, gas diffusion in the porous media, electrochemical reaction in the catalyst layer and the VOF (Volume of Flow) model for the water transport in the gas channel.The stack's geometrical model has been established nearly the same as the real one. The porous media model is used to decrease the computing quality. And simulation of the cathode and anode gas field is carried on according to this model. The result shows that the gas distribution in anode is good but the velocity is too low to flow the water away; the gas field of cathode is of great difference because of the air needed is much more than the hydrogen and the inlet manifold is too long; The difference is nearly 4 times between the most one and the least one; the air flow is increasing from the inlet to the outlet in manifold.Then, the performance of single fuel cell is analyzed using the PEM module of computational fluid dynamics software Fluent. The single fuel cell in different place could get a different gas feed. The result shows that the performance of single fuel cell becomes better as the gas supply improved. But in the last half stack, the increase is smaller. The performance of the whole stack is achieved by adding the single fuel cell's together.The VOF (Volume of Flow) model is used for modeling the water block in...