Large eddy simulation of molten steel flow and inclusion transport in single plug ladle

Abstract

Based on a 120-t single plug ladle in a steel plant, a full-scale three-dimensional unsteady steel-slag-gas three phase coupled flow model was established to calculate the multiphase flow field and temperature field inside the ladle during the soft blowing (inclusion removal stage) under different bottom-blowing pressures and initial temperatures. On this basis, the discrete phase model combined with a user defined function was employed to simulate the motion, collision, flotation and removal of inclusions in molten steel. Considering the smoothing effect of the k-ε model and the fact that the driving force acting on inclusions mainly originates from the molten steel, large-eddy simulation was adopted to describe the turbulent flow more accurately and obtain more realistic inclusion motion. The results show that LES captures more detailed flow structures than RANS, leading to a more accurate prediction of inclusion removal efficiency. The inclusion removal rate increases with bottom-blowing argon pressure; at 8 min, the removal rates under 0.2, 0.35 and 0.5 MPa are 70.1%, 74.2% and 76.4%, respectively. Taking 0.35 MPa as an example, the removal rate exceeds 98% within 24 min, and then increases by only to 0.718% between 24 and 30 min. Meanwhile, the initial temperature has a limited effect on inclusion removal efficiency.