Study on motion behavior of bubbles in argon blowing through a tundish stopper rod

Argon blowing through the stopper rod is a key technique in the continuous casting process for preventing nozzle clogging and improving molten steel quality. To optimize the stopper rod argon blowing process in continuous casting tundishes this study establishes a 1∶1 water-argon physical model based on a prototype tundish from a specific plant and combines it with numerical simulation. The study systematically investigates the influence of argon blowing hole position casting speed argon flow rate and stopper rod opening on argon bubble behavior flow field and turbulent kinetic energy distribution.The results indicate that the B1 position located above the sealing face of the stopper rod head yields optimal performance as its gas flow can effectively scour the sealing face. At an argon flow rate of 3 L/min bubbles are able to fully enter the nozzle at specific stopper rod openings corresponding to different casting speeds: specifically 33.75 mm at 1.3 m/min, 36.80 mm at 1.5 m/min and 41.90 mm at 1.7 m/min.Casting speed has a significant effect on bubble motion. For instance at a 30 mm opening and a 3 L/min argon flow rate increasing the casting speed from 1.3 m/min to 1.7 m/min increases the average bubble diameter from 12.5 mm to 15.1 mm. Conversely this speed increase reduces the average flow area width from 51.9 mm to 42.7 mm. Adjusting the argon flow rate simultaneously alters bubble volume and their range of motion within the nozzle. When the argon flow rate is reduced from 5 L/min to 1.8 L/min, the average bubble diameter decreases from 18.1 mm to 12.4 mm. Consequently the average bubble flow area width narrows sharply from 47.8 mm to 32.7 mm.The B1 position is suitable for a stopper rod opening up to approximately 40 mm with smaller openings generally resulting in better blowing effectiveness. However if the opening exceeds 50 mm the gas streams merge or float upward. This behavior not only loses the scouring effect on the stopper rod head but also increases the risk of erosion to the stopper rod at the molten steel surface in the tundish.