Model Study On The Formation And Suppressing Of Free Surface Vortex During Steel-teeming Process By Water Moder

In the continuous casting process of steel, the vortex of slag entrainment will be generated during the steel-teeming process. And slag entrainment brings a lot of harms, reduces the cleanliness of steel and affects the billet surface quality. Suppressing the formation process of the free surface during the steel-teeming, which reduce the critical height of vortex, can greatly reduce the volume of the slag entrainment and improve the steel quality. In this study, with a 60t ladle as a prototype, a water model scaled for 1/4 was built according to the similarity principle. It studies the formation of the surface vortex through the water model and analysis the influence of the standing time, the initial level, the nozzle diameter, the nozzle position (the nozzle eccentricity) on the forming height and the critical height of the vortex. The tangential velocity distribution under the different levels is analyzed and the vortex formation rule is obtained. Based on the previous experiments, this paper studies the suppressing vortex formation in both the center nozzle and the eccentric nozzle by blowing. And the effects of suppressing the vortex through different blowing method (including the blowing hole position and the blowing volume) are analyzed. The main conclusions are as follows:(1) During the steel-teeming process, the forming height and the critical height of the vortex decreased with the increase of standing time. The forming height and the critical height of the vortex rise with the increase of the initial height and then remained constant. The forming height and the critical height of the vortex rise with the increase of the nozzle diameter, descend with the increase of the nozzle eccentricity.(2) During the steel-teeming process, the fluid tangential velocity decreases with the level increasing at the same time. It indicates that the vortex begins to form from the ladle bottom. The tangential velocities are different under different condition during the steel-teeming process, but their distribution regularities are the same. The larger the tangential velocities are, the greater the forming height and the critical height of the vortex are. To reduce tangential velocity can reduce the forming height and the critical height of the vortex.(3) It can disrupt the velocity distribution in the process of the formation of vortex by blowing, which can effectively suppress the vortex. As for bottom blowing, there is an optimal blowing volume. If the blowing volume is less than the optimal blowing volume, the critical height of vortex decreased with increasing blowing volume. If the blowing volume is higher than the optimal blowing volume, the critical height of vortex enlarges with increasing blowing volume. The blowing position affects the suppressing vortex. The further the blowing is from the nozzle, the weaker the effect of suppressing vortex is. Compared with the center nozzle position, the eccentric nozzle blowing volume of is smaller than the center nozzle blowing volume. For side wall blowing, the suppression of vortex effects by blowing hole position height, and it is less than bottom blowing.