Swirl Motion of a Bubbling Jet in a Cylindrical Bath with an Immersion Cylinder

The deep-water wave type of swirl motion of a bubbling jet appearing in a cylindrical bath agitated by bottom gas injection is promising to elevate mixing efficiency significantly in the steelmaking industry. At the same time, it affects the erosion of the refractory of the reactor and causes oscillation of the reactor. An understanding of the swirl motion observed under different conditions therefore is of practical importance. Considering these circumstances, an effect of a top lance on the swirl motion is investigated in this study based on water model experiments. A hollow cylinder which is a model for the top lance is slightly immersed in a water bath contained in a cylindrical vessel. The cylinder and the vessel are concentrically placed. Air is injected through a centered bottom nozzle into the bath to generate the swirl motion. The occurrence condition of the swirl motion is revealed and empirical equations are proposed for describing the condition. Empirical equations are proposed also for the basic characteristics of the swirl motion such as the period, amplitude, starting time, and damping time.