Analysis of Transient Transport and Entrapment of Particle in Continuous Casting Mold

A mathematical model has been developed to simulate the transient turbulent flow, solidification, transport and entrapment of particles in a continuous casting mold. The turbulence of molten steel inside the liquid pool is calculated using the large eddy simulation (LES). The enthalpy-porosity approach is used to simulate the solidification of steel. A Laplacian equation is used to approximate the pull velocity in the solid region. The transport of particle (bubble and non-metallic inclusion) inside the liquid pool is considered according to the Lagrangian approach. A criterion for particle entrapment in the solidified front is developed using the user-defined functions (UDF) of FLUENT software, considering force balance involving eight different forces acting on a particle at the mushy-zone. The predicted asymmetrical flow pattern is compared with the water model experiment results. The entrapped positions of particles in the solidified shell are predicted and compared with the ultrasonic flaw results of rolled steel plates and the previous study of inclusions distribution in slabs. The model has successfully reproduced many known phenomena and other new predictions, including the transient asymmetrical flow pattern, transient asymmetrical distribution of particles inside the liquid pool, transient entrapment ratios and asymmetrical positions of different particles in the solidified shell.