Study On The Formation And Stability Behaviors Of Argon Film On The Wall Of Argon Blowing Nozzle

In order to prevent the nozzle clogging during continuous casting,the argon blowing techniques in tundish nozzle were employed in the actual production generally.The effects of process parameters on the formation of argon bubbles,the critical diameter of bubble that separate the upper nozzle wall,the formation and migration behaviors of gas film on the upper nozzle wall,and the sizes and movement behaviors of bubble in SEN were studied in this paper,by the aid of theoretical analysis and water model experiments.The main results in this study are as follows:Theoretical analysis results show that the gas film on the upper nozzle wall is continuous when the gas permeable brick have very small sizes and evenly distributed air holes;whereas,that is bubbles chains when the gas permeable brick have bigger sizes and smaller amount air holes.The critical diameter of bubble that separate the upper nozzle wall decreases with the increase of the amount of argon blowing and the angle of tangent direction of the upper nozzle wall and vertical direction,and the decrease of the diameters and amounts of the effective air holes.In the bottom of the upper nozzle,the critical diameter of air bubbles that separate the upper nozzle wall is large.Experiments results show that the number of air bubble chains on the upper nozzle wall gradually increases with larger amount of argon blowing.There is a continuous air curtain on the lower part of the upper nozzle wall due to the superposition of bubble chains.The range of the continuous air curtain is larger with the increase of the water flow rate due to the superposition of bubble chains.The migration velocity of argon bubble decreases on lower upper nozzle wall,while that increases with the increase of the casting speed.The average distance between the gas chain and the wall gradually decreases with the increase of the water flow rate in the given amount of argon blowing,while that gradually increases with the increase of amount of argon blowing in the given the water flow rate.The formation behavior,the migration behavior,and the distribution status of argon bubbles upper nozzle during argon blowing process has been clarified in this paper,which could provide theoretical basis for to the regulatory mechanism of continuous and stability argon gas film on the nozzle wall,and the parameter optimization of the blowing argon parameters and permeability of upper nozzle in order to prevent the clogging of tundish nozzle.