Prediction of turbulence suppression and turbulence modeling in bubbly two-phase flow

Abstract

An analysis was made on the turbulence suppression phenomenon in bubbly two-phase flow, which is characterized by a smaller turbulent kinetic energy than that in single phase flow. Based on the rigorous basic transport equation of turbulent kinetic energy which is derived by the authors, discussions were made on the turbulence suppression phenomenon and interfacial transport terms of turbulent kinetic energy. Dependence of the turbulence suppression phenomenon on liquid velocity and the ratio between bubble diameter and macroscale of turbulence is well explained by detailed considerations of interfacial transport terms. Based on the basic transport equation of turbulence kinetic energy and appropriately given constitutive equations of turbulent transport terms, predictions were made of the radial distribution of turbulent kinetic energy in the bubbly flow. The prediction successfully reproduced the turbulence suppression and turbulence augmentation which are observed in the experiment. The turbulence generation term and turbulence absorption term due to the bubble-eddy interaction are found to play the most important role in the turbulence suppression phenomenon in bubbly flow.