Simulation of Fluid Flow in the Top–Bottom Combined Blowing Converter

Abstract

The flow in the top–bottom combined blowing converter has an important impact on processes such as slagging, dephosphorization, decarburization, the heating of molten steel, and the homogenization of steel composition and temperature. A 1/6 reduced scale model based on a 210 t converter was used for the mathematical simulation. The validity of the model was verified by comparing the variation in cavity sizes caused by changes in the lance height and flow rate of the physical model with the numerical results. It was found that, in the bottom blowing converter, the area with higher velocity was distributed in the inverted conical plume. In top blowing, the area with higher velocity was distributed on the surface of a molten bath. The area of higher molten bath velocity in the combined blowing converter further increased. Compared with the top blowing converter, the increased percentage of the area-averaged velocity in the combined blowing converter first increased and then decreased as the distance from the bottom increased. When the top blowing flow rate changed, the combined blowing made the velocity change at the top of a molten bath smaller. The decrease in lance height significantly reduced the ratio of “inactive zone”, while the effect of the change in the flow rate was slight.