Pore scale study of heat and mass transfer in ice-containing gas diffusion layer of polymer electrolyte membrane fuel cells

Abstract

The liquid water transport and ice melting process in gas diffusion layer (GDL) are studied using the enthalpy-based multi-component multiphase flow lattice Boltzmann model. Then the heat and mass transfer process under different inlet heating temperatures, inlet flow velocities, rib-channel width ratios and contact angles of carbon fibers are discussed. The results show that heat convection and heat conduction areas are formed in the GDL, and the increase of the inlet heating temperature promotes ice melting, the heating temperature needs to be high enough to promote the reduction of the mixture content of water and ice. The inlet flow velocity has a great influence on both the ice melting efficiency and the discharge of liquid water. The reduction ratio of melting time from 0.5 m/s to 1.0 m/s is larger than that from 1.0 m/s to 1.5 m/s. The wider rib structure reduces the range of heat conduction region, so it has higher ice melting efficiency. The surface wettability of carbon fibers has no significant effect on ice melting rate in the heat convection area. Overall, the more hydrophilic the surface, the sooner the ice melts, but the more hydrophobic the surface, the more favorable the discharge of liquid water.