Mathematical Modelling of the Effects of Transient Phenomena on Steel Cleanness during Tundish Transfer Practices

摘要

Transient phenomena during tundish transfer practices have shown to be detrimental for the significance of clean steel production. These have become a distress for steelmakers; for this reason, there is opportunity for innovation in molten steel transfer devices, such as the dissipative ladle shroud. In the present modelling study the performance of this devise is fully analysed in order to quantify its efficiency in the reduction of the emulsification phenomenon and the slag aperture areas using a mathematical model to simulate a real steel-slag-air multiphase system during the ladle change-over practice. The most relevant results show that the convectional ladle shroud delivers a very turbulent steel flow generating strong mixing patterns, entrapping massive amount of air and slag into the tundish bath promoting a continuous emulsification and a permanent aperture of the slag layer. These phenomena are significantly reduced by using the dissipative ladle shroud technology since this innovative design reduces the emulsification phenomenon in more than a 50% and could decrease the steel re-oxidation by the reduction of the slag layer aperture in about 80%, all in comparison to the conventional ladle shroud; these will represent a diminishment in the amount of declassed steel to a less demanding application.