Abstract: For the problem of large residual steel during ladle teeming in a steel factory, the physical simulation was carried out to investigate the effects of ladle long nozzle diameter, nozzle eccentricity and slag thickness on the critical starting height of vortex and penetrating height (the liquid height of air column penetrating through the nozzle) during liquid draining. The results showed that the critical height of votex increased with increasing nozzle diameter. The starting votex height and penetrating height rised from 89.6，25.6mm to 165.0 and 40.7mm respectively for the simulated ladle when the nozzle diameter varied from 30mm to 60mm. The penetrating height of drain sink votex varied slightly with different nozzle positions when nozzle eccentricity was within 0.7, however, its value dramatically rised when nozzle eccentricity increased from 0.7 to 0.8. The optimum nozzle position was at 0.7R from the center of the ladle bottom. The critical slag entrapment height rised with the increasing layer thickness non-linearly. The slag entrapment height increased by 10mm when model slag thickness rised from 40mm to 50mm under the condition of 50mm of nozzle diameter.

Key words: ladle, sink vortex, slag entrapment, critical height, physical simulation