Abstract:Injection characteristics of side-blown lance in a bath smelting furnace directly govern reaction intensity and smelting efficiency. In this study, stirring enhancement mechanism of a novel side-blown lance with an adjustable rotation angle was investigated by computational fluid dynamics (CFD), and structural parameters of the lance were optimized. A volume-of-fluid (VOF) multiphase flow model coupled with the realizable k-ε turbulence model was employed to conduct transient simulations of gas-liquid two-phase flow in an oxygen-enriched side-blown smelting furnace. Influence of lance rotation angle (0°, 15°, 30°, 45°, and 60°) on flow field and mixing performance of the molten bath was analyzed. Results indicated that lance rotation angle exerted a nonlinear control effect on bath hydrodynamics. A moderate rotation angle (around 30°) effectively enlarged gas-induced disturbance region, accelerated interfacial renewal, and improved the uniformity of bath stirring. In contrast, either a non-rotating angle (0°) or an excessively large rotation angle (60°) led to pronounced flow drift and deteriorated local mixing. Overall, the proposed side-blown rotatable lance, through appropriate optimization of rotation angle, can enhance bath stirring while simultaneously ensuring furnace lining integrity and prolonging lance service life. The findings provided a theoretical basis and engineering guidance for lance design and optimization in large-scale oxygen-enriched side-blown smelting furnaces.