Numerical investigation of 3D bubble growth and detachment

Combined with new numerical techniques, the boundary element method is adopted to study the 3D bubble growth and detachment from a submerged nozzle under constant pressure conditions in this paper. During the bubble growth, an efficient mesh topology optimization technique is adopted to eliminate ill-shaped elements for large deformation problems. At the bubble detachment, a 3D bubble pinching algorithm is employed to deal with the topological changes automatically. In this study, the cases with or without liquid cross flow are simulated numerically and the mechanism of bubble dynamic behaviors is analyzed. 3D results without cross flow show good agreement with the experimental and axisymmetric results in the literature, which validates the 3D numerical model. Besides, with the existence of the cross flow, the effects of cross flow velocity and nozzle radius on the bubble detachment characteristics are studied. The simulation results show that the bubble frequency and shape at the detachment can be controlled by exerting different cross flow velocities.