Modelling transport of species at bubble interfaces with a combined level set and volume of fluid method

Modelling electrochemically gas-evolving systems like alkaline water electrolysis and Hydrogen production requires a multiphase and multiphysics approach. Optimizing the efficiency of these systems demands an understanding of the generation, growth, and dynamics of bubbles as they absorb or release dissolved gas in the fluid. Modelling transport of species between the bubble and fluid requires a precise bubble interface and conservation of mass. The volume of fluid method conserves mass, but inherent numerical diffusion smears the interface and produces spurious velocities. Alternatively, the level set approach does not suffer from numerical diffusion of the interface but does not conserve mass. We use a hybrid solver that combines the level set and volume of fluid approaches to both conserve mass and accurately model the interface. Combining the hybrid solver with a transport of species model in OpenFOAM, we model rising bubbles in reactive and non-reactive flows. The model produces similar results to experiments and accurately captures the stationary growth rate. We also present studies that demonstrate the impact of transport of species on the evolution of rising bubbles.