Evaluation of Mold Electromagnetic Stirring in Slab Continuous Casting Based on the Steel/Slag Interface Behavior

A new two-way coupled magnetohydrodynamic (MHD) model considering the dynamics change of electromagnetic force at steel–slag interface was established to investigate the multiphase flow and slag entrapment in slab continuous casting under mold electromagnetic stirring (EMS). The transient turbulent flow and the steel–slag interface behavior were described by solving the large eddy simulation (LES) model and volume of fluid (VOF) model. The level fluctuation, the location, and net mass of slag entrapment were quantitatively evaluated. By comparing the predicted level height within the in-situ measurement, the results show that the two-way coupled MHD model can better reveal the multiphase flow under EMS. The type of slag entrapment is closely related to the flow pattern, the vortex formation is predominant under the lower EMS current, while it changes to the shear-layer instability under the relatively high EMS current, the proportion of vortex formation slag entrapment decreases to 30.7 pct under the EMS current is 600 A. The tendency of net slag entrapment rate is the same as that of level fluctuation, with the increase of EMS current and casting speed, both the level height and net slag entrapment rate decrease firstly and then increase. Therefore, it is necessary to match the casting speed and EMS current to avoid the slag entrapment in actual production. The net slag entrapment rate is 0.034 kg/s, under the condition of 1.2 m/min casting speed and 600 A EMS current.