On the turbulence modelling of bubble plumes

Proper turbulence modelling of bubble plumes is critical for accurate simulation of liquid phase and bub-ble dynamics. The k-epsilon turbulence model is widely used. However, the model is unsatisfactory due to not accounting for the following physics: (1) turbulence damping in the vicinity of a free surface; (2) turbulence modifications created by non-uniform distribution of the bubbles; (3) extra turbulence agitation by bubble wakes. In order to remedy these deficiencies, an enhanced turbulence model has been developed, followed with application to a literature experiment of a gas-stirred ladle. The model framework is an Eulerian-Lagrangian large scale interface-capturing computational fluid dynamics (CFD) approach, coupling a volume-of-fluid model with discrete phase model. The implications of each physical process in turbulence modelling are investigated. The detailed model-experiment comparisons indicate that the enhanced turbulence model allows improved representation of the physics of bubble plumes, as well as the transport phenomena at, and close to, the free surface. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Proper turbulence modeling is crucial for accurate simulation of bubble plumes, with an enhanced turbulence model developed to address the deficiencies of the widely used k-epsilon model. The enhanced turbulence model allows for improved representation of the physics of bubble plumes and transport phenomena near the free surface.