Numerical simulation and multi-objective optimization on flow performance of novel alkaline water electrolyzer

The main development direction of producing hydrogen in the future is water electrolysis, but the electricity cost of water electrolysis is higher compared to other methods. During the electrolysis process, the products will cover the electrode surface in the low-speed zone due to the uneven distribution of electrolyte flow rate in the flow channel, which hinders the supply of reactants and increases the energy consumption of water electrolysis. The concave-convex mastoid polar plate can effectively improve the uniformity of gas-liquid distribution in the flow channel and is widely used in commerce. This article establishes a three-dimensional model of the electrolyzer with mastoid plates and studies the influence of the mastoid's structural parameters on the electrolyzer's performance using numerical simulation methods. It is found that as the diameter of the mastoid process increases, the uniformity of electrolyte velocity distribution in the channel gradually improves, but the pressure drop between the inlet and outlet of the electrolyzer gradually deteriorates simultaneously. When the diameter of the mastoid increased from 9.06 mm to 9.56 mm, the uniformity of electrolyte velocity distribution increased by 6.49 %, and the pressure drop also increased by 1.80 %. Therefore, this article proposes a new type of electrolyzer with a varied-diameter structure and optimizes the new structure based on the multi-objective genetic algorithm. Compared with the original structure, the optimized structure improves the uniformity of electrolyte velocity distribution by 8.40 %, and the pressure drop is still lower than the original structure. The research results have a guiding significance for commercial electrolyzers' development and structural optimization.