Numerical studies on liquid water flooding in gas channels used in polymer electrolyte fuel cells

Abstract

Water management plays an important role in the development of low-temperature polymer electrolyte fuel cells (PEFCs). The lack of a macroscopic gas channel (GC) flooding model constrains the current predictions of PEFC modeling under severe flooding situations. In this work, we have extended our previously developed one-dimensional channel flooding model for including phase change and liquid water flooding on the anode side. Several case studies are conducted to explore the effects of inlet relative humidity, net water transfer coefficient and GC shape on water film flooding in the GCs on both sides with the assumption that, both GCs are free from water droplets for simplicity. We demonstrate that the present model is capable of capturing key phenomenon of liquid water flooding in GCs. Our primary results show that gas drag force prevents liquid water accumulation in GCs, which dominates the liquid water removal. Both inlet relative humidity and stoichiometry can influence the liquid water flooding in GCs dramatically. At last, it is shown that increasing the upper half corner angle of the GC can mitigate the film water flooding in GCs.