MODELING WATER CONTENT DISTRIBUTION IN THE POLYMER ELECTROLYTE MEMBRANE OF PEM FUEL CELL

Models play an important role in fuel cell design and development. One of the critical problems to overcome in the proton exchange membrane (PEM) fuel cells is the water management. In this work a steady state, two dimensional, isothermal model in a single PEM fuel cell using individual computational fluid dynamics code was presented. Special attention was devoted to the water transport through the membrane which is assumed to be combined effect of diffusion, electro osmotic drag and convection. The effect of current density variation distribution on the Water content (lambda) in membrane/electrode assembly (MEA) was determined. After that detailed distribution of oxygen concentration, water content in membrane, net water flux and different overpotentials were calculated. Simulation results show that the reduction of reactant concentration in flow channels has a significant effect on electrochemical reaction in the gas diffusion and catalyst layer. Different fluxes are compared to investigate the effect of operating condition on the water fluxes in membrane. The amount of different fluxes is a strong function of current density which is related to external load. The model prediction of water content curves are compared with one dimensional model predictions data reported in the validated open literature and good compatibility were observed. In addition, the model predicted fuel cell polarization curves compared well with experimental and numerical data.