Modeling Research of the Impact of Liquid Water in Channel on Gas and Water Transport in Proton Exchange Membrane Fuel Cell

Water management in channel plays a crucial role in influencing the performance of proton exchange membrane fuel cell (PEMFC). However, the limited comprehensiveness of existing model has hindered the investigation of this phenomenon. To investigate the impact of liquid water transport in channel on overall water and gas transport, as well as the performance of PEMFC, this study modifies the existing model by incorporating factors such as the channel wall wetting properties. Specifically, contact angle hysteresis is incorporated into the model. Based on the modified model, this study investigates the impact of liquid water in channel under various operational conditions and channel design schemes. The results demonstrate that the existence of liquid water in straight channel increases the liquid water saturation in gas diffusion layer while reducing the optimal inlet humidity and operating temperature. When relative humidity (RH) is around 0.5, the difference in the prediction results of the performannce of PEMFC is greatest when considering whether liquid water in channel is present or not. Channel wall with larger static contact angle and smaller hysteresis contact angle reduces liquid water volume fraction within channel, thereby enhancing oxygen transport while decreasing membrane water content.