TURBULENCE MODELING IN BUBBLY TWO-PHASE FLOWS.

摘要

Experiments have indicated that for bubbly two-phase flows through a vertical pipe, the bubbles tend to collect in the wall region for upflows and in the core region for downflows. Analysis has indicated that the turbulent-induced pressure field in the continuous phase and the lateral lift force acting on bubbles cause the observed phase distributions. In this study, the well established K-(epsilon) turbulence model of single-phase flows was generalized to predict turbulence in two-phase flows. Basically, terms accounting for bubble-induced drag, turbulent kinetic energy, and dissipation rate were added to the corresponding transport equations in the single-phase K-(epsilon) model. The model was used to calculate the mean velocity, and turbulence level of the liquid phase, and void distribution in fully developed two-phase pipe flows. These results were compared with our experimental data and with the data of other investigators. Good agreement was found.