In the last three decades, continuous casting has become increasingly important in steel production and nowadays it is the most important step in the manufacture of steel. The fluid flow and heat transfer phenomena in a continuous casting mold are very complex and these phenomena affect considerably on the product quality. Therefore the understandings of the fluid flow and heat transfer phenomena in continuous casting mold have become important. Particularly, value of solidified shell thickness in the mold outlet is very important. Becouse, the solidified shell must be thick enough to withstand the ferrostatic pressure of molten steel. Due to the very high temperature of process, the direct measurement of velocity and temperature distribution is difficult. Thus numerical simulation is an important tool and provides more complete knowleges. In this study, a model is proposed on the basis of the technical and operational conditions of the slab caster in the continuous casting unit of Mobarakeh Steel Company. A three dimensional mathematical model using Fluent finite-volume software was developed for simulation of turbulent flow and heat transfer in continuous slab casting mold by bifurcated nozzle. Gambit software was used to create geometry and mesh generation. To predict the correct flow pattern in the mold, the solution domain including the nozzle, mold and small part of secondary cooling zone was considered. The turbulent flow is mathematically described by the Reynolds averaged Navier-Stokes equations (RANS). The realizable k - ? model and Reynolds stress model are used to close the RANS equations. The non-equilibrium wall functions near the wall are used to capture the steep gradients with accuracy on a coarse grid. Enthalpy-porosity technique has been used for solidification process. In this method a source term, derived from Darcy’s law of porous media, is incorporated in the momentum and turbulence equations. Due to the convergence problems in simulation of solidification process (as use of enthalpy-porosity technique), the problem was solve in transient state. Convergence criterion is establishment of the energy balance on the boundaries of solution area. According to the results, quantities as flow velocity, height of free surface oscillation, temperature and thickness of solidified shell were determined. The upper recirculation and lower recirculation flows were predicted truly. Level fluctuations of meniscus weas calculated using pressure distribution along the free surface based upon potential-energy conservation. The temperature distribution is vigorously dependent to the velocity distribution. The uniform distribution of temperature obtained that is important for slab quality. Reynolds-stress model didn’t have any advantage toward k-? model, although, it had more computational expense (CPU time and memory). This is due to the more sensibility of Reynolds-stress model to
