Analysis of two-phase flow evolution of the parallel skeleton flow field in proton exchange membrane water electrolyzers based on the volume of fluid-coupled method

Proton exchange membrane water electrolyzer (PEMWE) are regarded as one of the most promising green hydrogen production devices, boasting advantages such as zero emissions, high hydrogen production efficiency, and excellent long-term stability. The polarization performance and mass transfer characteristics of PEMWE are largely governed by factors such as the flow field configuration and the aggregation of oxygen bubbles, which remain key constraints for performance enhancement. This study focuses on investigating the two-phase flow evolution process in parallel skeleton flow field (PSFF) using the Volume of Fluid (VOF) method, aiming to improve the operational performance of PEMWE. In this paper, two structures with three-parallel skeleton flow field (3-PSFF) and five-parallel skeleton flow field (5-PSFF) are designed, and the skeleton surface is divided into upper, middle and lower sections to regulate contact angle distribution. The results indicate that among all configurations of the 3-PSFF, the contact angle gradient of 30°–50°–70° delivers the optimal oxygen discharge performance, accompanied by the lowest average pressure drop in flow channels. For the 5-PSFF, the uniform contact angle configuration of 50°–50°–50° achieves the best comprehensive performance. Through systematic analysis, it is concluded that hydrophilic contact angle layouts can effectively enhance the working performance of PEMWE. The findings of this study provide theoretical guidance for the structural optimization and performance improvement of PEMWE.