Liquid water transport phenomena in the porous transport layer of proton exchange membrane fuel cell based on lattice Boltzmann simulation

Abstract

The porous transport layer (PTL) of proton exchange membrane fuel cell (PEMFC) plays an important role in water management. The liquid water transport behavior with real density ratio and viscosity ratio is discussed by establishing a multi-relaxation time (MRT) multiphase flow lattice Boltzmann model. The effects of temperature, wettability and microporous layer (MPL) thickness on the water transport process and water distribution are included. As the temperature increased from 278.15 K to 353.15 K, the water saturation in the PTL decreased from 0.501 to 0.219. The breaking phenomenon of water clusters are captured at temperatures of 328.15 K and 353.15 K. The hydrophobic structure has less water content under the ribs and the whole, which is beneficial to the reaction gas transport and the performance improvement of PEMFC. Adding MPL with a thickness of 25 µm can significantly improve water management. However, excessively thick MPL will drive water to flow under the ribs and reduce the permeability of the structure. Appropriate MPL thickness design is a feasible solution to improve water management.