Numerical simulation of collision-coalescence and removal of inclusion in split swirling flow tundish

The swirling flow generated by the swirling chamber of the split swirling flow tundish can effectively promote the collision and growth of inclusions. The split swirling flow tundish can promote the removal of inclusions by improving the flow field. In this work, the CFD-PBM coupling model was applied to simulate the transport, aggregation, and floating removal of inclusions in the split swirling flow tundish, and compared with a same-size T-type tundish. The results indicated that the swirl flow can effectively promote the collision-coalescence of inclusions. Comparing the flow field of the split swirl tundish and the T-type tundish, the dead flow fraction of the two tundishes is similar, but the plug flow fraction of the split swirling flow tundish is 4.5% larger than the T-type tundish. Monitoring the volume concentration of inclusions at the outlet of the two tundishes, the inclusion removal rate of the T-shaped tundish and split swirling flow tundish are 29.28% and 34.33%, respectively. Therefore, the split swirling flow tundish is stronger than the T-shaped tundish in removing inclusion. Especially in the removal of small inclusions, the number density of 1.00–28.64 µm inclusions at the outlet of the split swirling flow tundish is 29.97%–65.91% lower than the T-type tundish, the split swirling flow tundish enhances the removal of small inclusions.