Assessment of Turbulence Models for Prediction of Intermixed Amount with Free Surface Variation Using Coupled Level-Set Volume of Fluid Method

摘要

In continuous casting tundish steelmaking, old ladle is replaced by new one to ensure continuous supply of steel from tundish to mold. Bath height changes in case of ladle change-over. To bring the bath height level to normal height, the flow rate of liquid steel from the new ladle is increased. This has a direct bearing on the fluid flow pattern and resultant intermixed amount formed. In the present work, assessment of Reynolds-averaged Navier-stokes (RANS) equations based standard k-ε, Renormalization group (RNG) k-ε, Realizable k-ε standard k-ω, and Shear-stress transport (SST) k-ω turbulence models have been carried out for prediction of free surface level of steel in tundish during ladle change-over and the intermixed amount formed. Coupled Level-Set Volume of Fluid (CLSVOF) method was used for free surface tracking in the three dimensional, multi-phase numerical model. Physical investigations were carried on water model setup of reduced scale tundish. Inflow rate of steel into the tundish from second ladle was varied due to which free-surface height of water varied and grade mixing in tundish was analyzed. Results obtained through physical investigations were compared with that of numerical investigations. The predictions revealed that RNG k-ε model have good approximation of F-curves as well as the interface between the two phases. Predictions made by all models except SST k-ω model have shown a satisfactory approximation with the experimental values. Free-surface interface profiles predicted by variants of k-e models were seen to closely match with experimental data.