Simulation Of Slag-Steel Interface Fragmentation And Coiling Mixing Behavior In Bottom Argon Blown Ladle

Furnace refining is the basic link and guarantee to improve the quality of molten steel and grade of steel.As the most widely used method of out-of-furnace refining,bottom blowing of ladle has great influence on cleanliness of steel and final quality of steel products.In view of the fact that the slag layer crushing mechanism caused by the argon blowing process at the bottom of the ladle is still unclear,the size and distribution of the slag droplets in the bath have not been revealed and mastered.In this paper,the argon blowing is performed on the bottom by the combination of physical water model experiment and numerical simulation.In the process,the slag layer interface fracture and slag behavior were studied,and the mechanism of slag crushing and mixing in the bottom blown ladle was revealed.The main contents of the thesis are as follows:(1)According to the similarity theory,a physical simulation system for simulating the bottom slag layer crushing and mixing behavior of the bottom blowing ladle refining process is established.The ladle top slag with different composition properties was developed.The motion,deformation,fracture,slag drop size distribution and volume mixing behavior of the slag layer in the ladle under different process parameters were measured and analyzed by high-speed camera and computer image processing.The study found that the main modes of slag fracture are pocket fracture and tongue fracture,and the main mechanism of fracture is interface instability and shear fracture.As the gas flow rate increases,the slag layer fracture frequency increases,the number of slag droplets increases,and large particle slag droplets begin to appear.When the gas flow rate is more than 10 NL/min,12 mm slag droplets appear.When air flow rate increases from 3 to 10 NL/min the slag droplets are mainly distributed between 2.3mm and 5.2mm,and the slag droplets are mixed from 61.63mm to 169.5mm,the number of slag droplets appearing locally increases,and the particle size becomes larger as the thickness of the slag layer increase.(2)By establishing a CFD-DPM-PBM coupled mathematical model,the top slag movement,crushing and coil mixing behavior in the bottom-blown ladle.The physical simulation results are used to verify and improve the mathematical model,and to reveal the internal mechanism of top slag breakage under the action of turbulence,as well as the movement,size distribution and involvement behavior of micro-droplets generated.It is found that the slag-steel interface shearing is the dominant mechanism of slag layer fracture;as the gas flow rate increases,the size of the top slag eye becomes larger,the number density function of slag droplets increases,and the mixing depth of slag droplets increases,k and epsilon in the ladle increase;as the oil layer thickness increases,the number density function of the slag drops increases,and the diameter of the slag eye decreases;as the viscosity of the slag layer material becomes larger,the edge of the slag eye becomes clear,the diameter of the slag eye becomes larger,and the number of slag drops The density function becomes smaller.