Effect of cavity shape caused by jet impact of swirl-type oxygen lance on molten bath mixing efficiency

In top-blowing steelmaking, the shape and size of the cavity formed by a supersonic jet have impacts on the molten bath, which is crucial for the refining process. This study used physical experiments to explore the influences that the operation and structural parameters of swirl-type oxygen lance have on cavity shape and mixing time. The results demonstrate that the lance height has a greater influence on cavity shape than flow rate, and the influence that the inclination angle has on cavity shape is greater than that of the swirl angle. Compared to the traditional oxygen lance, the mixing efficiency of the swirl-type oxygen lance increased by 5%–13.3%. When the cavity shape index of the swirl-type oxygen lance for the 260 t converter is in the range of 0.46–0.5, the mixing effect of the molten bath is the best. Additionally, an improved cavity depth prediction model of the swirl-type oxygen lance was proposed using the previous studies.