Numerical Simulation of Liquid Water and Air Flow in Separator-Channels in PEM Fuel Cell Using LBM

In a polymer electrolyte membrane (PEM) fuel cell, the condensed water in the separator-channel prevents the supply of reactants to electrodes, which deteriorates the cell performance. The Lattice Boltzmann simulation has been developed to understand the behavior of condensed water in the separator-channels. The calculation process was improved, and the effect on the stability and reliability of simulation of two-phase flows with large density difference was confirmed. Further, the comparison with experiment of the falling water droplet by gravitation on the slope of micro porous layer was conducted to validate effectiveness of the improved simulation. It was shown that the simulation can express the increase in falling speed of water droplet and the effect of inclined angle of the slope, and our simulation is effective enough to estimate the liquid water and air flow in the separator-channel. Finally, the simulation of liquid water behaviors in separator-channels with various cross-sectional shapes was conducted, and the drain efficiency of water droplet of separator-channel was discussed.