Author(s): M Liu; L Tan; S L Cao; B B Wang

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Keywords: Bubble rise; Initial stage; Separation behavior; Large eddy simulation; Volume-of-fluid method

Abstract: The numerical investigation has been carried out on the initial stage of bubble free rise in still water. The simulation and analysis focus on the separation behavior of air bubbles. The Large Eddy Simulation (LES) and Volume-of-Fluid (VOF) methods are applied as the turbulence model and multiphase model, respectively. The bubble behavior and flow field are analysed to reveal the mechanism of bubble separation. The predicted results show that there exists a funnel shape air gathering on the injection hole of water tank, and the air bubbles are separated from the upper part gradually. The separation behavior of air bubble results from the back flow induced by vortex structure. The strength difference of vortex in both sides is the major cause of zigzag motions of streamlines and bubbles.

DOI: https://doi.org/10.1088/1755-1315/163/1/012121

Year: 2017