Abstract

Computational Fluid Dynamics (CFD) modelling is increasingly being used for studying various metallurgical processes. In secondary steelmaking, gas stirring is used in ladles to enhance the mixing of the steel. This work aims at numerical study to investigate the effect of different closure models on of the flow analysis in a two-phase gas-stirred ladle. The study represents a cylindrical geometry, in which liquid Wood’s metal represents the liquid metal phase and nitrogen gas is injected through nozzle located centrically or eccentrically at the bottom of the vessel. Three-dimensional CFD simulations were carried out using the commercial software package ANSYS FLUENT using Euler-Euler multi-phase model. To study the influence of turbulence models on the accuracy of the CFD analysis, three different models Standard k-ε, k-ω and Reynolds Stress Model (RSM) were employed. Furthermore, four different gas flow rates (100, 200, 500 and 800 cm3/s) were used for studying the effect of gas flow rates on the flow velocities. The simulation results were compared with the available experimental data of the liquid velocity profiles, volume fraction of gas and turbulent kinetic energy at different heights in the ladle. The RSM model showed a good accuracy of results when compared to experimental results, but it requires more computational time when compared to other turbulence models. The simulation results using the liquid Wood’s metal/nitrogen system were compared to water/air and liquid steel/argon systems to check the effect of material properties on the flow velocities in the ladle. The results provide useful guidelines for numerical modelling of fluid flows in steelmaking ladles and suggest that the RSM turbulence model is better suited for studying gas injection in metallurgical ladles than k-ε or k-ω models.