Effect of operation parameters on supersonic jet behaviour of BOF six-nozzle oxygen lance

A three-dimensional mathematical model of compressible supersonic free surrounding jets from six convergent-divergent nozzles oxygen lance was developed based on the Reynolds averaged Navier-Stokes equations. The modelling results were validated by experiment. A comparison between the standard k similar to omega turbulence model and realisable k similar to epsilon was carried out, and it shows that the standard k similar to omega turbulence model is superior in being able to depict the flow characters of multiple jets. The effects of nozzle inclination angle and operation pressure on jet flow characteristics and coalescence behaviour were investigated, and the mechanism of jet coalescence is discussed. The results show that coalescence patterns of six nozzle jets are strongly affected by the inclination angle but hardly by the operation pressure. When jets impinge on the melt surface in a BOF, the nozzle inclination angle plays also an important role in the splashing phenomena and the shape of cavity. It can be expected that when the nozzle inclination angle reduces from 17.5 to 10 degrees, the cavities impinged by jets evolve from several scattered small craters to one large cavity. The change of jet coalescence pattern leads to different splashing patterns of the melt.