Effect of the Shape Parameter on Droplet Behavior in Multiple Channels of a Proton-Exchange Membrane Fuel Cell

Abstract

Understanding the two-phase flow within multiple channels in a proton-exchange membrane fuel cell (PEMFC) is important to improve cell performance. In this study, the droplet behavior in multiple channels is predicted by the volume of fluid (VOF) method. In addition, the pressure drop and velocity and pressure distribution between the multiple channels are analyzed, and the effects of channel wettability, gas velocity, and structure parameters on the two-phase distribution within the multiple channels are investigated. The effect of different parameters on the droplet detachment time in multiple channels is evaluated by comparing the droplet movement time. The results show that the increase in amplitude and period leads to greater improvement in the water removal performance of the multiple channels. Additionally, the unevenness within the multiple channels is improved as the interval between channels decreases. The channels show better water removal performance at a channel period of 4, an amplitude of 1.2 mm, and an interval of 1 mm. With the lowering of the wall contact angle, the broken droplets tend to accumulate at the wall corners, and the time for the droplets to be removed increases significantly. It is also observed that as the inlet velocity increases, droplet breakup is more likely to occur in the third channel. At larger flow rates, the droplet detachment time from the channel decreases to some extent in all three channels, but the droplet detachment order is different due to the unevenness of the flow distribution of the two-phase flow in the multiple channels compared to a single channel. Therefore, this unevenness in the flow distribution is the cause of the different droplet detachment orders in the three channels. This study is important for the design of the flow channel and water management of the PEMFC.