A Continuum Model of Solidification and Inclusion Collision-growth in the Slab Continuous Casting Caster

A coupled mathematical model on fluid flow, heat and solute transport, and inclusion transport is developed to investigate turbulent flow, solidification, and inclusion collision-growth in the slab continuous caster. The behaviors of inclusion and solute in the steel belong to mass transfer phenomena, but inclusion transport is different from solute transfer in the liquid phase zone, mush zone and solid phase zone. In the continuous caster, turbulent collision and Stokes collision, which are the major factor causing inclusions to coalescence, have been taken into account in the mathematical model. All these differential equations have the same basic structure and can be solved by the same numerical method. Influenced by the fluid flow, the temperature, carbon element and inclusion in the molten steel have similar spatial distribution as the fluid flow in the continuous caster. Their spatial distribution can be divided into the upper and lower recirculation zones, but their distributions have their own characteristics. Near the center of the recirculation zones, the temperature of molten steel and the characteristic inclusion concentration and the characteristic inclusion number density are lower, but the carbon concentration and the inclusion size are greater. Due to the interaction between the movement of solidified shell and the downward flow, a small corner-vortex appears near the meniscus. The initial solidified shell forms near the meniscus, so there is a few of indigenous inclusions with small size in the initial solidified shell.