| In the current study,the effects of different flow control devices and process parameters on the flow of molten steel,inclusion removal and reoxidation of molten steel by air of the slab continuous casting(CC)tundish were investigated through establishing a three-dimensional numerical simulation model.Firstly,the effects of different turbulence inhibitor structures,immersion depth and structure of shroud on multiphase flow of molten steel,slag entrainment,and wear of refractory materials of the tundish were investigated by combining three-dimensional k-εturbulent model and VOF multiphase model.The residence time distribution and flow pattern of a water model was used to validate the mathematical model of steady pouring of the tundish.The smaller the average turbulent kinetic energy of the steel level,the less slag entrainment on the steel level.Compared to turbulence inhibitor without eaves,turbulence inhibitor with eaves can reduce the mass of slag entrainment to 19.3 kg.The mass of slag entrainment of the straight shroud,diffusive shroud,and dissipative shroud were 22.4 kg,17.2 kg,and 17.8 kg,respectively.Next,the effects of flow control devices on the residence time of molten steel and inclusion removal rate were discussed through a three-dimensional mathematical model,combining the k-ε turbulent model,VOF multiphase model,and Discrete Phase Model,based on the consideration of the influence of the natural convection induced on the fluid flow.The accuracy of the model was verified through the temperature measurement results during the actual production process of the tundish.The results indicate that the inclusions with diameter less than 10 μm were mainly removed on both sides of the shroud,while the removal position of inclusions with diameters greater than 100 μm were more dispersed.The removal rate of inclusions increased with the increase of particle diameter,and the removal rate of large dimension inclusions by turbulence inhibitor with eaves reached74 %.Finally,the diffusion of dissolved oxygen in the steel was predicted through establishing a mathematical model for reoxidation of molten steel by air of the tundish.The initial concentration of dissolved oxygen was 3.45 ppm,and it was basically stable after 650 s of diffusion of dissolved oxygen.The concentration of dissolved oxygen increased by 0.535 ppm due to reoxidation.The effects of casting speed,initial concentration of dissolved oxygen,and interfacial tension between steel and slag on the equilibrium time and concentration of dissolved oxygen in molten steel were discussed,providing theoretical guidance for optimizing the reoxidation of molten steel during the casting process of the tundish. |
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