Numerical Simulation of Inclusion Aggregation and Removal in the Gas-stirred Ladle

A comprehensive study of inclusion aggregation and removal in different bottom gas-stirred ladles has been conducted. The unsteady, three dimensional, isothermal, multiphase computational fluid dynamics (CFD) model was developed. A ladle with two bottom plugs was used in the study. Effects of plug separation angles (180° and 90°) and argon flow rate combinations (5/5 SCFM, 5/20 SCFM and 20/20 SCFM) were investigated. The whole study can be divided into two parts: first, the flow field, slag eye size and wall shear stress have been studied; second, inclusion aggregation and removal in different ladles have been investigated. In the first part, argon bubble breakup and coalescence has been considered. The slag eye size was validated with plant measurement. When the flow rate increases, the size of slag eye will increase while the wall shear stress increases as well. In the second part, a parametric study of ladle design and argon flow rate on inclusion aggregation and removal has been conducted. Turbulence shear collision shows the most dominant effect on inclusion aggregation. The argon flow rate is positively related to inclusion aggregation and removal. When the argon flow rate is fixed, a larger plug separation angle shows higher inclusion aggregation and removal efficiency.