Numerical simulation on the motion of bubbles and inclusion removal in the swirling long nozzle

Abstarct Improving the removal rate of inclusions is crucial for enhancing the quality of steel products. The paper designs a swirling flow generator (SFG), which is installed between the ladle and the long nozzle, to optimize the efficiency of converting gravitational potential energy of the molten steel into swirling kinetic energy within the long nozzle. Compared the effects of the discrete phase model (DPM) and the DPM-volume of fluid (VOF) on the removal of inclusions during bubble injection, where the collision elimination behavior of inclusions and bubbles was simulated using a self-developed user-defined function (UDF), which optimizes the collision determination between bubbles and inclusions from a time point approach to a time step method, enabling full-process monitoring of bubble-inclusion collisions within discretized time steps. The results indicate that the application of the SFG significantly optimizes the flow field in the long nozzle, compared to the traditional long nozzle (TLN), the inclusion removal rate in the swirling long nozzle could be increased by approximately 50% and 20% using the DPM model and DPM-VOF coupled model, respectively.