Abstract: Aiming at the problem that the method of visual analysis of fluid motion in tundish by RTD curve combined with water model flow field is complicated, and the distribution of dead zone cannot be accurately given. In this paper, the analysis method of fluid motion pattern model in continuous casting tundish was proposed. Based on the analysis results of RTD curve obtained by physical simulation, the dead zone was determined by numerical simulation, and the relationship between the critical velocity of dead zone and the inlet velocity was determined. Based on the critical velocity of the dead zone, the proportion and regional distribution of the dead zone can be determined in real time and online by numerical simulation, and then the fluid motion patterns in the single-strand and multi-strand tundish can be evaluated. The influence of casting speed and tundish structure on the proportion and regional distribution of dead zone in tundish was investigated. The results show that the fluid motion morphology model can quickly determine the dead zone of tundish and realize the quantification and visualization of dead zone. At the same time, compared with the same single-strand tundish, the critical velocity of dead zone increases with the increase of casting speed, while the volume fraction of dead zone is opposite, and the distribution pattern of dead zone does not change. In addition, the size and regional distribution of the dead zone under different baffle hole diameters and elevation angles in the multi-strand tundish can be intuitively compared. When the hole diameter is 70 mm and the elevation angle is 19°, the volume fraction of dead zone in the multi-strand tundish is only 7.64 %, and the dead zone is concentrated near the central nozzle and the side wall.

Key words: tundish, dead zone volume, RTD curve, numerical simulation, flow control device, casting speed