Formation factors of confluence vortex in double nozzle ladle at end of teeming
At the end of ladle teeming,when the molten steel level is reduced to a certain height,a funnel-shaped con-fluence vortex will be formed in the ladle due to the interaction of viscosity of molten steel,initial tangential velocity and Coriolis force.Once the vortex penetrates into the pouring nozzle,the slag and air will be involved in the molten steel and pollute the molten steel.Therefore,it is necessary to accurately control the formation and penetration height of the vortex in production,so as to close the pouring gate in time when the vortex is formed.Additionally,by optimizing the process parameters of ladle to delay the generation of vortex,the steel residue in ladle can be reduced and the metal yield increased.There are few studies on the characteristics and influencing factors of vortex at the end of double nozzle ladle teeming.A 150 t industrial double-nozzle ladle in service was used as the prototype.Based on the similarity principle,a 1∶3.5 physical model was established by organic glass.The effects of ladle stand-ing time,initial height of liquid level,nozzle position and structure,bottom blowing stirring and anti-vortex device on the formation process of vortex at the end of pouring were studied by water simulation.The results show that the standing time of molten steel and the initial height of liquid level have no significant effect on the formation height of vortex,while the nozzle position has a great influence on the formation height,and almost no effect on the penetra-tion height.When the eccentricities of two pouring nozzles are 0.60 and 0.83 respectively,the formation height of vortex is the smallest with 17 mm.Compared with a funnel-shaped nozzle,the square-shaped nozzle can reduce the formation height of vortex.In addition,under the present experiment conditions,the bottom blowing stirring opera-tion is not conducive to controlling the vortex,whereas setting an anti-vortex device near the connection line of the two nozzles at a distance of 0.6R(R refers to the radius of the ladle bottom)from the center of the ladle bottom will reduce the formation height of vortex,which is conducive to the suppression of vortex.
ladledouble nozzleend of teemingphysical simulationconfluence vortex
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