Liquid Holdup in the Bipolar Plate Channels of a PEM Fuel Cell

摘要

Numerical simulations using Surface Evolver are employed to determine the minimum liquid volume (critical volume) necessary to form a plug in a square channel of mixed wettability. The critical volume has direct implications on the water distribution in the flow fields of a PEM fuel cell, as well as on the pumping parasitic power loss. The liquid plug is placed in a channel bend having a contact angle on the GDL wall fixed to 110° and 150°. For each considered GDL, the critical volume is determined for different contact angles on the bipolar plate walls, ranging from 50° to 130°. The numerical data allows one to determine the liquid holdup in a channel bend of mixed wettability. These correlations can be used as an optimization tool for water management in channels of non-uniform wettability, accounting for the contact angle of the GDL and of the bipolar plate sides, as well as the in-plane geometry (bend dihedral).