Numerical simulation and analysis of a two-phase flow model considering bubble coverage for alkaline electrolytic water

Abstract

The electrolysis of water to produce hydrogen is thought to be one of the most promising strategies to achieve carbon neutrality. However, the evolution of bubbles causes possible hindrances to its mass mobility between electrolytic solution and catalyst because they envelop the catalyst surface, which ultimately leads to a reduction in conversion efficiency. At present, the correlation between vigorous bubble evolution and electrolytic water performance has not been thoroughly investigated. Therefore, to quantitatively analyze this correlation, this work constructs an integrated model of the alkaline electrolytic cell based on COMSOL software that considers the effect of bubble coverage. The results show that increasing the bubble contact angle facilitates the generation and separation of bubbles and can decrease bubble coverage's effect on the electrolytic cell's current density at the same voltage. The current density can increase from 850 A/m2 to 1100 A/m2 with an increase in bubble contact angles from 90 ° to 140 ° at an electrolytic cell voltage of 1.83 V. In addition, although increasing the operating temperature (50–80 °C) enhances the negative effects due to bubble coverage, increasing the temperature still can increase the hydrogen production efficiency. Therefore, it can be believed that the work in this paper may guide the development and utilization of alkaline electrolytic cells.