Optimization Of Flow Control Device And Gas Bubbling In Thin Slab Continuous Casting By Physical Modeling

In this paper, a one-strand thin slab continuous casting tundish was considered as a research target, and a definite scale physical model was established in the laboratory by using law of similarity. Effect of shape and location of weir and dam, configuration of turbulence inhibitor, position of gas bubbling curtain (GBC) in the tundish as well as gas flow rate on the fluid flow characteristics were studied in detail, which results realized the aim of optimization for the tundish flow modifier. Some conclusions were obtained as follows:1) Under this experimental condition, when a weir-dam combination is used as substitute of single dam, the best design project of weir-dam combination is that, the distance between weir and nozzle is 422mm-522mm, the center distance between weir and dam is 290mm-350mm, the weir depth is 170mm and the dam height is 200mm. Compared with the original project, minimum residence time increases from 42s to 52s, peak concentration time increases from 183s to 188s, however, dead zone volume is still large.2) On the base of optimum project of dam and weir, the short circuiting decreases obviously by reducing the section 50% of the spout nozzle on the dam. Compared with the project before the optimization experiment, minimum residence time increases from 42s to 79s, peak concentration time increases from 183s to 234s, furthermore, dead zone volume decreases from 26.9% to 18.3%, the fluid flow characteristics improves obviously.3) The physical simulation experiment of turbulence inhibitor showes that, effect of the big square turbulence inhibitors with waved bottom in the laboratory showes an obvious increase for the characteristic parameters, which can be used as substitute of the original turbulence inhibitor.4) Based on the optimum weir-dam combination and turbulence inhibitors, a gas bubbling curtain is added at some position. When the position is at the stage edge, and gas flow rate is 0.02m3·h-1, minimum residence time is 68s, peak concentration time is 282s, dead zone volume is 13.9% respectively.5) When a gas bubbling curtain is installed on the top of dam, the optimum project is that, the distance between gas bubbling curtain and the inlet is 862mm, gas flow rate is 0.04m3·h-1. Minimum residence time is 55s, peak concentration time is 279s and dead zone volume decreases to 10.0%.6) Under this experimental condition, it is completely feasible by using the gas bubbling curtain replacing dam or weir. Compared with the conventional weir-dam combination, some parameters, such as the minimum residence time and dead zone volume has been improved.7) When gas bubbling curtain is used as substitute of wire-dam in the tundish, minimum residence time reaches to 62s, peak concentration time is 214s, and dead zone volume is 22.8%. However, the dead zone volume is still larger.