Development of Advanced Cfd-Based Model for Anion Exchange Membrane Water Electrolyzer

Recently, various computational fluid dynamics (CFD)-based water electrolysis models have been developed to analyze the internal phenomena of water electrolysis cells for green hydrogen production. Anion exchange membrane water (AEM) electrolysis is a promising and inexpensive solution to address hydrogen production and environmental issues. AEM electrolysis requires high fidelity to improve its durability, reliability, and efficiency, because of its low technical proficiency. In this study, a CFD-based model for AEM electrolysis was developed to analyze the three-dimensional and two-phase phenomena inside the cell. By combining electrochemical models with mass, momentum, and heat transfer models the temperature, pressure, and gas generation profiles inside the cell were studied. Parameters were estimation using the experimental data from a high-accuracy model. The results showed that the applied voltage, which determined the exothermic/endothermic mode, had a significant effect on the water electrolysis performance. The current density and activity of the gas generation reaction increased as the voltage increased. Specifically, in the exothermic mode, with voltages higher than the thermo-neutral voltage (1.48 V), the amount of hydrogen generated (28.15 and 32.75 mol/m3 at 1.7 and 2.0 V, respectively) was higher than that in the endothermic mode (11.92 mol/m3 at 1.45 V). However, the increased gas generation caused a rapid increase in the temperature and pressure drop inside the cell, which adversely affected the durability. The cell design also had a significant effect. The model developed in this study can be used in experiments of various scales to optimize serpentine designs and commercial AEM electrolysis stack developments.