Numerical study on water transfer characteristics under joint effect of placement orientation and flow channel size for PEMFC with dead-ended anode

Abstract

Proton exchange membrane fuel cell (PEMFC) with dead-ended anode is of outstanding advantages of high hydrogen utilization and simple hydrogen system. Because of its unique operation mode, the effect of gravity on water and gas transportation in PEMFC with dead-ended anode cannot be ignored. A two-phase model of PEMFC with dead-ended anode was developed, and the effects of placement orientation and cross section sizes of flow channel on water transport characteristics were analyzed. The results show that the flow channel with smaller cross section (0.5mm × 0.5 mm) showed better initial performance, but its voltage drop rate was faster due to liquid water was easier to be accumulated in the channel. Conversely, the liquid water volume fraction was smaller with a larger flow channel size. Moreover, the volume fraction of liquid water at the end of the channel was significantly greater than that in other areas when it was placed vertically. According to the results, the flow channel placed vertically combined with a larger cross section size (2mm × 2 mm) could effectively transferred liquid water to the end of the flow channel. Thus, it can effectively reduce the damage to PEMFC caused by water accumulation.