Removal of inclusion through bubble curtain created by swirl motion in submerged entry nozzle

Abstract

In the steel-making processes, it is well known that suspended non-metallic inclusions can be removed by Ar gas bubbles injected in the steel baths. This study aims to remove the inclusions through a bubble accumulated zone (namely, bubble curtain) created by swirling motion imposed on the flow in a submerged entry nozzle. The results obtained through water model experiments and numerical calculations (Eulerian/Lagragian, Eulerian/Eulerian method) show as follows; the swirling motion works effectively to form a bubble curtain through that all the flow pass, and the half vertical angle of the bubble curtain increases with the increasing swirl strength. On the other hand, inclusions pass nearly parallel to the axis of the submerged entry nozzle, the trajectories of them being similar to the liquid-phase flow pattern. Therefore, a chance for a bubble and an inclusion to meet with each other would significantly increase.