Numerical Investigation for the Influence of Turbulent Heat Transfer of Mushy Zone on Shell Growth in the Slab Mold

Abstract

The turbulent heat transfer in the mushy zone caused by the impinging of molten steel jets in the slab mold has a significant effect on the growth of the solidified shell and the formation of impinging zone, as well as the quality of steel products. In the present work, a Peclet number of the mushy zone (Pem) is proposed to analyze the influence of turbulent heat transfer on the shell growth in the mushy zone and define the boundary of the impinging zone. A three-dimensional mathematical model based on the enthalpy-porosity method has been established to predict the flow, heat transfer and solidification processes in the slab mold. The influences of casting speed and secondary dendrite arm spacing (SDAS) on the turbulent heat transfer behavior are also investigated. The results indicate that the turbulent heat diffusion has a great effect on the formation of the impinging zone and is the only source of energy to maintain the boundary of the impinging zone. The Pem can evaluate the turbulent heat transfer in the mushy zone and is a more reasonable method to obtain a clearer boundary of the impinging zone. The impinging zone is formed when the Pem reaches a critical value, been dependent on the casting speed and SDAS.