Liquid Water Effects on the Performance of a PEMFC With Serpentine-Parallel Channels

Water management is one of the most important issues for the performance of Proton Exchange Membrane Fuel Cell (PEMFC). Understanding of water liquid behaviors in the gas-liquid flow of PEMFC is necessary for the optimization of PEMFC. In this study, a three-dimensional and unsteady PEMFC model with serpentine-parallel channels has been incorporated to investigate not only the fluid flow, heat transfer, species transport, electrochemical reaction, and current density distribution but also the behaviors of water liquid in the gas–liquid flow of the channels and porous media. The results show that tracking the interface of water liquid in a reacting gas-liquid flow in PEMFC can be fulfilled by using Volume-of-Fluid (VOF) algorithm combined with solving the conservation equations of continuity, momentum, energy, species transport and electrochemistry. Consequently, the behaviors of liquid water were fully understood by presenting the motion and deformation of water droplets inside the channels and the penetration of liquid through the porous media at different time instants. Additionally, the presence of liquid water in the channels significantly influences the flow fields. Due to the blockage of water liquid, the gas flow became unevenly distributed, the high pressure regions took place around the locations where water liquid appears, and the reactant transport in the channels and porous media was hindered by water liquid occupation.