Investigation of Two-Phase Flow Interfaces in Gas Flow Channels of Proton Exchange Membrane Fuel Cells with Various Channel Parameters

Gaining a profound understanding of the dynamic interface characteristics of the two-phase flow within the gas flow channel holds immense significance in enhancing the water management capability and the overall performance of fuel cells. This study investigated the effect of the channel geometry on the two-phase flow interface behavior by utilizing experimental observation and numerical techniques. The findings suggest that reducing channel height increases the contact interface area between the two phases, promoting slug flow transformation to film flow. The two-phase interface formed in the depth direction under the same channel height is similar for different channel widths, resulting in a comparable time for the breakthrough slug to transition into a liquid film flow. With increasing channel width from 0.4 mm to 0.6 mm, a "spoon" like interface form, would facilitate the water movement but would develop into a slug in a circular channel. Therefore, reducing the flow channel size has a positive effect on avoiding liquid water blockage both in the depth direction and in the width direction, but the mechanism of the effect on the two-phase flow interface is different, reducing the channel depth can remove the slug flow faster while reducing the width can tend not to form a slug.