Study On The Fluctuation Of Liquid Level In Continuous Casting Mold

The level fluctuation in the mold has an important influence on the quality of the cast slab.In production,the wave height of the liquid is often monitored so as to better regulate other parameters.Turbulent level fluctuation may cause the slag wrapped on the surface,decreasing the billet quality,while too gentle fluctuation will cause the malfunction of slag melting,resulting in production accidents.Therefore,it is vital to main the surface wave within the mold in a reasonable range through appropriate adjustment of the relative parameters,which is crucial for improving the productivity of the continuous caster as well as the quality of the billet.In the light of Turbulent submerged jet theory,the current research establishes a theoretical model considering the molten steel flow's impact velocity and impact point on the narrow face of the mold during the casting process.An analytic formula of the level fluctuation index is deduced.The prediction result of the theoretical model is verified by comparing with the experimental outcome.A mathematical model of flow field in the continuous casting mold,whose accuracy is verified through field data,is initially built based on the Numerical analysis theory,with the parameters of industrial design taken into account.Steady and unsteady state solvers are used to solve the equation of flow field and surface wave in mold.Numerical simulation result is used to analyze the influence of SEN depth,casting speed and mold width and other parameters on level fluctuation whose general motion law is further summarized.The study also explains the reason for the raceway in the internal flow field of the mold and predicted the area that is prone to form slag entrapment.The result shows that the level fluctuation is more sensitive to the change of casting speed compared to other factors.As the SEN immersion depth decreases,the amplitude of fluctuation increases,which makes the upper raceway unstable and the flow field in the mold uneasy to reach the steady state.In the premise of confirmed casting speed,the increase of the mold width is unfavorable to the lowering of level fluctuation.The liquid level reaches its maximum in the vicinity of meniscus.The most vulnerable area for slagentrapment is about one fifth of the mold width to the narrow side.In a third of the way from the nozzle to the narrow face in mold,the slag layer is thickest and liquid surface is relatively steady.