Numerical simulation of thermal stratification and destratification in secondary steelmaking ladle

A two dimensional model was developed to model transient fluid flow and heat transfer for the molten steel in a secondary steelmaking ladle during the standing time and subsequent submerged gas injection. Lagrangian-Eulerian approach was employed to model two phase region in gas injection operation. It was observed that stratification develops due to natural convection. Therefore, the influence of gas stirring on thermal homogenisation was investigated. It was seen that bottom bubbling induces a recirculatory turbulent flow in the molten bath. Simulation attempts were performed to examine the effect of gas flowrate on the thermal homogenisation and resultant temperature field. The results indicate that an increase in gas flowrate accelerates thermal destratification and reduces final thermal gradients. Also, there is a minimum gas flowrate for a particular ladle situation and associated stratification, which can result in desired thermal destratification in the ladle.