Integrated performance evaluation of flow channel designs in zero-gap alkaline electrolyzers: A 3D multiphysics study

As alkaline electrolyzers evolve toward compact architectures, the flow channel has become critical to zero-gap electrolyzer design. This study develops a three-dimensional multiphysics model of a zero-gap alkaline electrolyzer coupling electrochemistry, two-phase flow, heat transfer, and gas crossover. Incorporating the supersaturated solubility of dissolved hydrogen enables three-dimensional calculation of hydrogen in oxygen contamination (HTO). Polarization characteristics and HTO are validated against experimental data. Four flow channel designs are systematically evaluated over a wide current density range. Flow channel design significantly affects gas removal and thermal management, with the serpentine channel performing best. Because bubble and temperature effects partially offset each other, flow channel design has limited influence on polarization characteristics, with a maximum voltage difference of only 0.26 %. Comparisons of dissolved hydrogen concentration distributions and HTO values among the four designs show that flow channel design indirectly influences gas crossover, mainly through changes in the temperature field.