Continuous Casting Immersion Nozzle Inner Wall Structure Study On The Influence Of Molten Steel Stream

In the continuous casting process,the problem of blockage of the tundish nozzle has always been one of the problems that plague the continuous casting production.The blockage attached in the nozzle will cause the phenomenon of bias flow and crystallizer liquid level fluctuation,which seriously affects the surface quality of the casting blank.The stability of the casting state has a direct relationship with the quality of the slab.Therefore,optimizing the nozzle structure is of great significance for solving the problem of nozzle blockage.In this paper,a slab mold with a immersion nozzle and a section of 1200 mm×200 mm is taken as a research object.The effects of different immersion nozzle structures on the flow behavior of molten steel inside the nozzle and the velocity distribution of the molten steel at the outlet are studied.The model was established by Solidworks and the flow field of the molten steel in the immersion nozzle and the velocity distribution of the molten steel in the immersion nozzle of the crystallizer were simulated by Fluent.Based on this,it was clarified that optimizing the internal structure of the immersion nozzle can improve the immersion.The molten steel flows in the nozzle to reduce the nodule near the water outlet and improve the impact depth of the molten steel on the crystallizer.1.In the hydraulic model experiment,the inner diameter of the immersion nozzle is 75 mm,the section of the slab mold is 1200 mm × 200 mm,and the speed of the mold is 1.3 m/min.The effect of optimizing the nozzle structure parameters on the liquid flow rate in the immersion nozzle was studied.The experimental results show that after adding the hemispherical crown inside the immersion nozzle,the liquid flow rate inside the immersion nozzle is smaller than that in the immersion nozzle without the hemispherical crown added.2.In the numerical simulation,the liquid velocity inside the immersion nozzle is in good agreement with the experimental results of the hydraulic model.At the same time,the numerical simulation results show that after adding the hemispherical crown inside the immersion nozzle,the liquid in the nozzle produces a velocity on the horizontal section to generate a swirling flow;the outlet velocity is significantly attenuated and the impact depth is improved;the outlet stream is separated by a single jet.Becomes a swirling stream.The hydraulic model experiment and the numerical simulation results show that changing the immersion nozzle structure(adding the hemispherical crown to the inner wall)can reduce the internal flow velocity of the nozzle and simultaneously cause the liquid in the nozzle to swirl;the outlet velocity is obviously attenuated and the impact depth is improved.The outlet flow changes from a single jet to a swirling flow.Therefore,changing the inner wall structure of the immersion nozzle can improve the internal flow of the nozzle,reduce the nodule near the water outlet,and improve the impact depth of the molten steel on the crystallizer.