An Experimental Study of Relative Permeability of Porous Media Used in Proton Exchange Membrane Fuel Cells

This study investigated gas and liquid relative permeability, one of the important two-phase transport properties of the porous media used in proton exchange membrane fuel cells. The experiment showed that the gas relative permeability obtained by the gravimetric analysis and neutron imaging agreed at low saturation levels, but differs at high saturation levels. The liquid relative permeability in the saturation level range of 0.3 to 0.8 was measured by neutron imaging. Because of dead air pockets in the porous materials and certain saturation levels are required to establish continuous flow of liquid water through gas diffusion media, liquid permeability at both high and low saturation levels could not be obtained. It was shown that the 3rd-order power correlation of gas permeability generally used in numerical simulation only fitted the porous media of A1 and A3 at low saturation levels.