Study on Air Bubble Plume in Open Channel with CFD-PBM Coupling Model

Abstract

Air bubble plume flow has been applied widely in the dredging, ice breaking, and pollution control at navigation projects. But the interaction regimes among bubbles or between bubbles and water are not quite clear. Especially in open channels, the bubble plume flow are significantly affected by the separation phenomenon which is caused by the cross flow velocity. According to the existing research, the interaction force of gas-liquid and the distribution of bubble size are the key parameters to simulate the hydrodynamic characteristics of bubble plume flow. In order to explore the mechanism of air bubbles entrained plumes in open channels, an Eulerian-Eulerian approach for air-water flows numerical model was introduced, and the population balance model (PBM) was included to describe the distribution of bubble size. The cross flow velocity of open channels has been discussed in the proposed numerical model. It shows that the separation of bubble plume is strongly influenced by the cross flow velocity. The influence of these parameters on the movement characteristics of air bubbles is studied. The results indicate that the cross flow velocity has great impact on bubble plume as well as the lifting effectiveness of pneumatic sluicing. This research provides references for bubble plume in engineering applications.