Simulation of Sliding Nozzle Gate Movements for Steel Continuous Casting

The slab surface quality is generally known to deteriorate when the casting speed fluctuates during the continuous casting of steel. The mold powder on the meniscus is more likely to be entrapped in the molten steel undergoing molten steel flow fluctuations due to a casting speed change. As the casting speed is controlled by the sliding nozzle (SN) gate movement, an investigation into the effect of such SN gate movement on the molten steel flow would be useful. In this study, the molten steel flow in a mold was numerically simulated during partial opening/closing of the SN gate by a certain distance at a constant speed. The deforming mesh model was used to consider the geometry change in the simulation. The validity of this model was confirmed by comparison with the results of a water model simulation experiment. When the SN gate is partially opened/closed, the steel mass flow rate is increased/decreased accordingly. At the SN gate and the SEN ports, the transitional time required to reach a steady flow is several seconds after the commencement of SN gate movement. At the meniscus, an even much longer time is required to reach a steady flow.