Development of a commercial code-based two-fluid model for bubble plumes

Bubble plume models are applied to study the de-stratification of lake water, aeration of reservoirs, wastewater treatment, and gas injection into liquid metals. Several existing models exemplify numerical modeling as problem-specific art, solve a mixture momentum equation, and have limitations in the availability of documentation, definition of boundary conditions, and post- and pre-processing capabilities. The transfer of problem-specific models to a client or to a multidisciplinary research and development team is a difficult process. The questions addressed in this study were as follows: (a) can one use a commercial code as a basis to develop a user-friendly, efficient model that simulates two-phase flow in bubble plumes? (b) what are the capabilities and limitations of such a model? The two-fluid model developed has flexibility in the definition of the multiphase and viscous models, easily understood definition of boundary conditions, simple definition of spatial dimensionality and time dependency, efficient numerical solution, clear documentation and user-friendly pre- and post-processing capabilities. Water and air phase velocities, water turbulent kinetic energy, and air volume fraction are predicted with accuracy similar to that of existing problem-specific models. A strategy to overcome some under-dispersion and include air-water mass transfer effects through user-defined functions is discussed.