Water transport in the gas diffusion layer of proton exchange membrane fuel cell under vibration conditions

Fuel cell vehicles face complicated road conditions, which may impact on the output performance of fuel cell stacks. In the present study, the water transport in the gas diffusion layer (GDL) of proton exchange membrane fuel cell (PEMFC) under vibration conditions are investigated. A stochastic method is employed to reconstruct the 3-D GDL with experimentally validated varying porosities. The volume of fluid (VOF) method is adopted to investigate the two-phase problems. Sinusoidal vibration source terms are superposed, which can vary with required amplitudes and directions. Over time, the water transport process takes three steps: water intrusion, water accumulation, and water removal. The water intrusion tends to start from the sides of the GDL, then spreads into the central area. Compared with the no-vibration case, the water saturations are higher in both the vertical and horizontal vibration cases. The vibration will enhance the water transport through GDL layers. As such, the higher the vibration amplitude and frequency, the larger the water saturation. Accordingly, the water saturation of the GDL vary sinusoidally over time. The water breakthrough paths are identified and compared during the water removal processes. Vibration in the horizontal direction is much easier to promote the water transport inside a layer compared with vibration in the vertical direction. More substantial water saturation in the GDL layers will restrict the gas transfer paths. Consequently, less oxygen will participate in the reaction, which will further impact on the fuel cell performance.