Enhancing Efficiency in Alkaline Electrolysis Cells: Optimizing Flow Channels through Multiphase Computational Fluid Dynamics Modeling

Abstract

The efficient operation of alkaline water electrolysis cells hinges upon understanding and optimizing gas–liquid flow dynamics. Achieving uniform flow patterns is crucial to minimize stagnant regions, prevent gas bubble accumulation, and establish optimal conditions for electrochemical reactions. This study employed a comprehensive, three-dimensional computational fluid dynamics Euler–Euler multiphase model, based on a geometric representation of an alkaline electrolytic cell. The electrochemical model, responsible for producing hydrogen and oxygen at the cathode and anode during water electrolysis, is integrated into the flow model by introducing mass source terms within the user-defined function. The membrane positioned between the flow channels employs a porous medium model to selectively permit specific components to pass through while restricting others. To validate the accuracy of the model, comparisons were made with measured data available in the literature. We obtained an optimization design method for the channel structure; the three-inlet model demonstrated improved speed and temperature uniformity, with a 22% reduction in the hydrogen concentration at the outlet compared to the single-inlet model. This resulted in the optimization of gas emission efficiency. As the radius of the spherical convex structure increased, the influence of the spherical convex structure on the electrolyte intensified, resulting in enhanced flow uniformity within the flow field. This study may help provide recommendations for designing and optimizing flow channels to enhance the efficiency of alkaline water electrolysis cells.

Keywords

• computational fluid dynamics
• alkaline water electrolysis for hydrogen production
• multiphase flow
• concave–convex structure