Effects of surface wettability on two-phase flow in the compressed gas diffusion layer microstructures

The surface wettability plays a significant role in two-phase flow in the gas diffusion layer (GDL). However, few reported researches have considered directional single gradient polytetrafluoroethylene (PTFE) distribution, PTFE immersion depth, and the GDL compression. In this study, effects of various surface wettability distribution schemes on two-phase flow in the GDL microstructures are investigated. In addition, the GDL deformation is also considered via clamping pressure simulation based on the finite element method (FEM). Two-phase flow in the compressed GDL microstructures is modeled using the volume of fluid (VOF) model. The results show that the direction of single gradient of the surface wettability is influential in two-phase flow, especially for the compressed GDL Moreover, thicker PTFE immersion depth contributes to water removal from the GDL. Finally, novel surface wettability distribution schemes are first proposed, and they are demonstrated as important references for controllable water transport in the GDL. (C) 2020 Elsevier Ltd. All rights reserved.