Modeling and analysis of water droplet dynamics in the dead-ended anode gas channel for proton exchange membrane fuel cells

Abstract

Proton exchange membrane (PEM) fuel cells usually operate in dead-ended anode mode due to a comparatively simple system. Nevertheless, flooding in the anode channels in dead-ended mode is severe than that in flow-through configuration, which causes cell performance degradation and durability decrease. In this study, water droplet dynamics in the anode channel is investigated numerically using volume of fluid method to study water accumulation and drainage in the PEM fuel cell with the dead-ended anode. Simulations are divided into a dead-ended stage and a purge stage to study the two-phase flow behaviors. Impact of water accumulating volume is taken into consideration and, cases of different wettability of the gas diffusion layer surface and the bipolar plate surface are compared. The numerical results reveal that water droplets emerge from the water inlets and then accumulate and coalesce in the dead-ended stage. Most water droplets are drained out of the gas channel along the channel corners in the purge stage. It is found that larger water accumulating volume results in higher eliminating rate. The total purge time is mainly affected by the wettability of the bipolar plate surface.