Three-Phase Flow in a Single-Strand Tundish During Start-Up Operation Using Top-Swirling Turbulence Inhibitor

A top-swirling turbulence inhibitor (TS-TI) was designed, and the three-phase behaviors of steel–slag–gas during the start-up operation with different TIs (without a TI, with an ordinary TI, with a TS-TI, and a TS-TI with different thickness of guide vanes) in a single-strand slab tundish were numerically and physically investigated and compared. The results showed that the molten steel exposed behaviors and residence time distribution (RTD) curves obtained by numerical simulations were consistent with the experiments. A swirling flow would be generated by using the designed TS-TI during start-up operation in the impact zone, thereby weakening the average velocity and level fluctuation of the steel–slag interface, and the steel exposure phenomenon at the whole filling process could be prevented when the thickness of guide vanes in the TS-TI was over 40 mm. After the molten steel level reached to steady-state level, exposed area of 1875 and 875 cm 2 for molten steel in the impact zone that without a TI and with an ordinary TI, respectively, and remains at 430 cm 2 when the guide vane thickness is 20 mm. Meanwhile, on applying the proposed TI, the time of slag adding operation could be 11.5 seconds earlier than that of an ordinary TI. Therefore, the TS-TI with the guide vane thickness around 40 mm could obviously improve the steel flow behavior, avoid steel exposure, and enhance the production efficiency of the single-strand tundish.