Enhancement of water droplet drainage performance in a cathode flow channel with baffles for a polymer electrolyte membrane fuel cell

Abstract

A reasonable design of flow channel is crucial for water management of a polymer electrolyte membrane fuel cell (PEMFC), and thus the cell performance. This paper develops newly designed baffles on a cathode flow channel to boost the water droplet drainage ability. The water droplet drainage characteristics within the novel flow channel are investigated by using a volume of fluid (VOF) method. The results show that the baffle height and number have a significant impact on the water droplet drainage performance. An appropriately increased baffle height and number leads to a shorter water droplet drainage time with a relatively low pressure drop. The water droplet drainage time for baffle height and number of 0.25 mm and 7 is reduced to 8.5 ms from 22.5 ms compared with that for the conventional channel. However, a too large baffle height and number could yield a very large pressure drop, thereby causing the water droplet detachment from the GDL surface and finally adsorption to the sidewalls. An optimal non-uniform interval layout of baffles along the channel can further shorten the water droplet drainage time by 6.25%. These findings can guide the optimal design of flow channels with baffles for a high-performance fuel cell.