Developing a New Type of Annular Flow Field Based on Murray’s Law in Proton Exchange Membrane Water Electrolyzers

The proton exchange membrane water electrolysis (PEMWE) technology is a highly promising method for hydrogen production. The flow field structure is a key factor affecting the electrolyzer’s performance and overall cost. The commonly used flow field designs are typically parallel flow fields or serpentine flow fields. However, parallel flow fields often suffer from an uneven distribution of reactants, which can negatively impact electrolyzer performance. Serpentine flow fields, on the other hand, exhibit higher pressure drops, leading to increased energy consumption. Furthermore, research on circular planar flow field designs in PEMWE has been limited. Therefore, this study proposes a novel annular flow field design based on a circular plane using Murray’s branching law, with comparative analysis against parallel and serpentine flow fields. This design aims to address the aforementioned issues. A three-dimensional numerical model coupling multiple physical fields was developed with the aim of verifying the effectiveness of the annular flow field design in terms of pressure drop, velocity distribution, temperature distribution, hydrogen distribution, and polarization curves. To confirm the model’s reliability, bipolar plates with the novel annular flow field were fabricated and assembled into a single cell for validation. The results show that the novel annular flow field exhibits optimal electrolytic performance and can significantly improve the uniformity of flow and temperature distribution in PEMWE. At a voltage of 2.6 V, the current density increased by 29.99% and 13.84% compared to the parallel and serpentine flow fields, respectively. The velocity distribution was the most uniform, and the average temperature of the Membrane Electrode Assembly (MEA) decreased by approximately 6.08 K and 6.84 K compared to the parallel and serpentine flow fields, respectively. Notably, the pressure drop of the annular flow field was significantly reduced, with reductions of 53.63% and 46.09% compared to the parallel and serpentine flow fields, respectively. This study provides an effective solution for the design of circular plane flow fields in PEMWE.