A bubble-induced turbulence model for gas-liquid bubbly flows in airlift columns, pipes and bubble columns

Abstract

The presence of bubbles dramatically changes the liquid turbulence in bubbly flows. Modifications to liquid turbulent transport equations by adding source terms representing the effect of bubble-induced turbulence (BIT) are usually made to promote the reliability of Computational Fluid Dynamics simulations. However, existing closures for BIT fail to give reliable predictions of both mean flow properties and turbulence kinetic energy. In this work, a new BIT model, which embeds both the bubble swarm effects and the physics of bubble-induced vortices, is proposed to modify the Reynold stress model for bubbly flows. The anisotropy nature of BIT is also considered. The new BIT model can predict both mean flows and turbulence kinetic energy in airlift column systems, while investigated existing BIT models from the literature fail. Three simulation test cases for pipes and one for a bubble column have been conducted to show the validity of the proposed BIT model.