Effect of slag properties and non-uniform bottom blowing gas supply mode on fluid flow and mixing behavior in converter

Bottom blowing plays an important role in improving the physical and chemical reaction speed in the molten bath of combined blowing converter. In this paper, physical and numerical simulations were performed to study the influence of slag properties and non-uniform bottom blowing gas supply mode on flow and mixing behavior of molten bath in a 210 t converter. Compared with the two-phase case, the average velocity in the three-phase case is lower and the flow field is asymmetric. The increase of slag thickness, viscosity and surface tension will reduce the average velocity of the molten bath and make the mixing time longer. The numerical simulation of ten cases is carried out to study the effect of partial blockage of the tuyere on the overall mixing. The results showed that the existence of the central vortex and the long horizontal flow are beneficial to promote the overall mixing, while the central collision and the vortex at the edge play the opposite role in the non-uniform mode. The smaller flow difference between the tuyeres is unfavorable to the mixing of the molten bath. Reasonable tuyere flow difference can promote the horizontal flow of the molten bath and improving the stirring force.