Towards a comprehensive, high-fidelity, multi-physics simulation framework for alkaline water electrolyzers

To enable the industrial upscaling of alkaline electrolyzers, a deeper understanding of all the different "physics" involved is needed. To this end, while the use of computational fluid dynamics (CFD) is essential, comprehensive 3D CFD models are still rare, with stack simulations often hampered by computational cost. The present study addresses this research gap by introducing a detailed multi-physics CFD model for alkaline electrolyzers, integrating two-phase flow, electrochemistry, thermal effects (including Faraday and Joule heat sources, plus reaction heating in the thermal equation) and interaction between anodic and cathodic half-cells. Moreover, unlike previous models, which simulate one cell alone, our approach allows for the simulation of any specific cell within the stack by enabling boundary conditions to be tailored for the positioning of the cell at hand. The model successfully replicated the expected fluid-dynamic and heating trend of a real-cell geometry and allowed highlighting critical areas for design improvement.