Physical and Mathematical Modeling of Swirling Gas Jets Impinging onto a Liquid Bath Using a Novel Nozzles-Twisted Lance

Physical and mathematical modeling is performed in a 10:1 scaled-down basic oxygen furnace (BOF) steelmaking vessel to study impingement onto a bath of swirling gas jets from a novel nozzles-twisted lance. The particular aspects with respect to the swirling jets-induced cavity characteristic, jets' stirring efficiency, and bath flow field are focused upon, and their discrepancies with those created by conventional oxygen lance jets are assessed. Results show that compared with the conventional jets, the swirling jets strike a greater impact area with a shallower but wider cavity and facilitate bath surface flow. Due to a more intensive bath horizontal flow, which shows an increase in intensity by 0.34-1.66 times than that of conventional jets, the swirling jets shorten bath mixing time by 11-60%, depending on the nozzle twist angle of the lance. These results suggest that the lance height of the nozzles-twisted lance is operated more flexibly than that of the conventional one. This not only enables sufficient bath stirring efficiency and improves slagging but also contributes to postponing lance tip erosion and prolonging its life span in plant operations, whereas the enhanced flows in the regions near the sidewall accelerate refractory erosion there.