Numerical Simulation Of PEMFC Flow Channel Based On VOF Model

Fuel cell technology is a clean and efficient energy conversion technology Water management is a key technology that affects the working performance and working efficiency of Proton Exchange Membrane Fuel Cell(PEMFC),and is currently a hot research topic at home and abroad.The cathode channel in PEMFC has more complicated flooding problems,which need to be analyzed and solved from the mechanism level.In this paper,the VOF(Volume Of Fluid)model is used to conduct an in-depth simulation study of the gas-liquid two-phase flow of liquid water in the battery flow channel.At the same time,three new serpentine flow channels are proposed based on the research of conventional direct current channels and conventional serpentine flow channels to further improve water management.The results show that the hydrophobic wall surface is more suitable as a gas diffusion layer(GDL)surface due to its low adhesion;the side wall needs a wall material that is more hydrophilic than the GDL surface to accelerate the generation of liquid water from the GDL surface and improve the efficiency and performance of the battery.However,the wall surface that is too hydrophilic will form an annular flow and hinder the transport of the reaction gas;when the initial water drop is located at the corner point,since the adhesion force of the corner and the wall is greater than gravity,most of the generated water will leave the GDL plane,which is conducive to the transmission of the reaction gas.For the serpentine flow channel,the hydrophilicity of the wall surface of the curved part should be consistent with the hydrophilicity of the side wall of the direct current channel to ensure the stability of the air flow in the curved channel.The serpentine double-slope flow channel has the best drainage effect in three new serpentine flow channels.The serpentine double-slope flow channel with the inner and outer curved walls inclined at the same time has the best drainage effect.The inner and outer curved walls of the serpentine flow channel are inclined at a certain angle at the same time,which is conducive to the stable discharge of the water generated in the curved channel.The angle of inclination should not be too large.The angle easily causes the airflow in the bend to be too concentrated,and the high-speed airflow distribution range is large,which leads to the instability of the liquid water flow.At the same time,due to the excessive intensity of the airflow disturbance,a large number of broken small droplets are generated.At this time,if the amount of water generated is large,it will increase the possibility of"water flooding".