Numerical simulation of liquid water emerging and transport in the flow channel of PEMFC using the volume of fluid method. (4th November 2020)

• Record Type: Journal Article
• Authors: Chen, Rouxian; Qin, Yanzhou; Ma, Suhui; Du, Qing
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 54(2020)
• Page Start: 29861
• Page End: 29873
• Publication Date: 2020-11-04
• Subjects: PEMFC -- Water flow -- Water detachment -- Flow velocity -- Surface wettability; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.07.169
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Three-dimensional numerical simulation of liquid water emerging from the gas diffusion layer (GDL) surface to the gas flow channel in the proton exchange membrane (PEM) fuel cell (PEMFC) is carried out using the volume of fluid (VOF) method. The effects of the water velocity in the GDL hole, the airflow velocity and the wettability of the channel surfaces on the water emerging process and transport in the flow channel are investigated. It is found that at low water velocity, the water detaches from the water hole, forming discrete water droplets on the GDL surface, and is transported downstream on the GDL surface until removed from the GDL surface by the U-turn part of the flow channel; whereas at high water velocity, the continuous water column impinges the hydrophilic channel surface counter to the GDL surface, being directly removed from the GDL surface. The airflow velocity affects water detachment and impact process in the channel corner, and water droplet breakup is observed under high airflow velocity. The channel surface wettability influences water droplet shape and its transport in the channel. Rather than forming corner water films at the U-turn for hydrophilic channel surface, water maintains the droplet shape and smoothly passes through the U-turn for hydrophobic channel surface. The importance of the U-turn to the water removal is also discussed. The U-turn promotes water removal from the GDL surface at low water velocity and water breakup at high airflow velocity. Highlights: Water removal modes from the gas diffusion layer surface depend on water velocity. Water directly impinges the channel surface and is removed for high water velocity. Small droplets are frequently detached from water hole for high airflow velocity. Surface wettability determines water flow patterns after impacting channel surface. U-turn of channel promotes water removal from the gas diffusion layer surface.