LES‐VOF simulation of turbulent interfacial flow in the continuous casting mold

Abstract

Slag entrainment during continuous casting process is a multiscale problem strongly dependent on the molten metal flow in the mold. Large-scale flow structures in the mold interact with the slag layer at the top of the meniscus, and small-scale liquid structures in the form of slag droplets may be entrained into the solidifying metal. In this work a large eddy simulation - volume of fluid (LES-VOF) approach is applied to investigate the unsteady flow interaction with the metal-slag-air interface including the interface instability, deformation of the slag layer and its entrainment into the molten metal. A benchmark experiment was designed to investigate the flow field in the proximity of a liquid-liquid interface for validation purposes. The experiment uses water and paraffinum liquidum to model the combination of liquid steel and the slag layer. While the entrainment of oil droplets can be visualized via shadowgraphy the flow field was measured via particle image velocimetry PIV. In combination, these two methods allow a qualitative and quantitative comparison of the unsteady flow characteristics with the CFD results. The measurement data at different inflow conditions have been used to validate the simulation results. We compare the global flow characteristics and mean velocity of submerged entry nozzle jet upon injection to the mold. Furthermore, the statistics of turbulence including velocity fluctuations and turbulent kinetic energy are used to investigate the unsteady jet interaction with the slag layer as well as liquid-liquid interface dynamics. The comparison of CFD results and experimental data reveals fairly good agreement both quantitatively and qualitatively.