Numerical studies on the geometrical characterization of serpentine flow-field for efficient PEMFC

Abstract

Geometrical characterization of the serpentine flow-field is one of the key issues to be solved to enhance the performance of PEMFC in relation to pressure drop, discharge of condensed water, maximization of cell voltage, and uniformity of current density over the entire surface area. Three different channel heights and widths were compared with the base flow-field design of the serpentine channel whose width is 1 mm and 0.34 mm in height, each through a detailed numerical study of the distribution of temperature, pressure, water content, and local current density. As the channel height increases higher than the base design, the total pressure drop decreases and results in reduced load of BOP and accumulation of liquid water at the outlet of both anode and cathode. The accumulation of anode liquid water at the outlet caused by back diffusion is accelerated as the channel height increases. As the channel width expands wider than the base design, the pressure drop is lowered and the removal rate of liquid water becomes faster. The effect of the channel width increase on the water removal is greater than that of the channel height increase. Which can influence the dehydration and temperature of the MEA and thus cell performance and lifetime of PEMFC. The results obtained in this work are expected to be applied in developing an efficient serpentine flow-field channel with sub-channels and by-passes.