COUPLED TURBULENT-FLOW, HEAT, AND SOLUTE TRANSPORT IN CONTINUOUS-CASTING PROCESSES

A fully coupled fluid flow, heat, and solute transport model was devel oped to analyze turbulent flow, solidification, and evolution of macro segregation in a continuous billet easter. Transport equations of tota l mass, momentum, energy, and species for a binary iron-carbon alloy s ystem were solved using a continuum model, wherein the equations are v alid for the solid, liquid, and mushy zones in the casting. A modified version of the low-Reynolds number kappa-epsilon model was adopted to incorporate turbulence effects on transport processes in the system. A control-volume-based finite-difference procedure was employed to sol ve the conservation equations associated with appropriate boundary con ditions. Because of high nonlinearity in the system of equations, a nu mber of techniques were used to accelerate the convergence process. Th e effects of the parameters such as casting speed, steel grade, nozzle configuration on flow pattern, solidification profile, and carbon seg regation were investigated. From the computed flow pattern, the trajec tory of inclusion particles, as well as the density distribution of th e particles, was calculated. Some of the computed results were compare d with available experimental measurements, and reasonable agreements were obtained.