Three-Dimensional, Two-Phase Computational Fluid Dynamics Simulations of Alkaline Diaphragm Water Electrolysis Devices

Abstract

Alkaline diaphragm water electrolysis (ADWE) devices are the most widely commercialized water splitting cells for large-scale applications. They are inexpensive and durable, but they undergo numerous voltage loss mechanisms that are absent in ion-exchange cells.1 Computational studies enable us to understand these losses and to engineer components that diminish them. Hammoudi et al.2 developed a validated one-dimensional multi-physics model incorporating bubble effects and compared relative overpotentials at different temperatures. Abdin et al.3 used a multi-physics approach that included electrode and separator properties to show effects of design parameters on performance.Our aim is to utilize computational fluid dynamics techniques to build an ADWE model that enables us to effectively engineer the flow field and porous transport layer (PTL). This two-phase model considers losses due to the presence of bubbles in the electrolyte, bubbles on the electrode surface, and shunt current through the diaphragm. We include a discussion of the current distribution in a straight channel ADWE device and what factors are important to consider for optimizing productivity and efficiency.