Three-dimensional numerical analysis of near-wall single-orifice ventilated bubble dynamics

摘要

Bubbling from near-wall orifices is widely used in ocean engineering, such as ship drag reduction, sewage treatment, underwater vehicle control technology and so on. But at present, most studies on ventilated bubble do not take into account the influence of the wall on the development of the bubble. Based on the potential flow theory, combined with mesh smoothing technique and mesh subdivision technique, the boundary element method is adopted to study the 3D ventilated bubble growth in this paper. The bubble is generated by ventilation during the vertical upward movement of the rotary body with a single horizontal orifice on the wall. And the convergence of the model is studied by modifying the mesh size. Meanwhile, the numerical simulation results agree well with the experimental results. Finally, with the existence of the inflow, the effects of different inflow velocities, ventilation rates, the diameters of the orifice and surface tension coefficients on the development process and flow characteristics of the bubble were studied. The results show that the inflow velocity is the main influencing factor of the bubble development process. The ventilation rate and the diameter of the orifice have some influence on the development process of the bubble. And the surface tension coefficient has little effect on the development process of the bubble.