转炉超音速氧枪喷头磨损后的吹炼特性变化

The oxygen lance nozzle of converter will be eroded to different degrees with the increase of lance age. In order to investigate the influence of oxygen lance erosion degree on the supersonic gas jet blowing characteristics, a three-dimensional full-size geometric model of 120 t converter and a supersonic oxygen lance were established, and the effects of different wear angles for oxygen lance nozzle on the gas jet characteristics, molten bath velocity, and wall erosion were studied. It is found that with the increase of wear angle, the jet velocity decays faster, the length of jet core area and the same isovelocity line are shortened, the maximum velocity of jet center and the distance from the maximum velocity point to the center increase. Dynamic pressure decay rate increases with increasing wear angles, the wear angle increases from 0 to 20°, the maximum dynamic pressure at 1.5 m from lance tip is reduced by 14.84%, and the 14 000 Pa isobaric envelope area is reduced from 0.038 m² to 0.002 m². The area of high-velocity zone at the liquid steel surface decreases with increasing wear angles, while the area of dead zone increases with increasing wear angle. The high-velocity area of longitudinal section for molten bath is mainly distributed near the impact dent and bottom blowing element, the low-velocity area is mainly distributed at the bottom of molten bath, and the dead zone is mainly distributed in the center of molten bath bottom and the lower part of furnace wall. In the depth range of 0.6 m below molten steel surface, the top blown oxygen jet plays a major role in the stirring of molten bath, the stirring ability of molten bath becomes weaker with the increase of wear angle, and the area of high-velocity zone decreases, while the area of low-velocity zone and dead zone increases. When the depth of molten bath exceeds 0.6 m, the bottom blowing airflow plays a major role in the stirring of molten bath, and the area of high-velocity zone is basically unchanged. The shear stress is concentrated in the slag-metal interaction area, the connection between furnace wall and bottom, and the wall near the bottom blowing stream, thus the erosion of refractories is serious. The turbulent kinetic energy and shear stress of fluid near the molten bath wall decrease with the increase of wear angle, and the erosion velocity of converter lining decreases.