Instability Phenomena at Bath Surface Induced by Top Lance Gas Injection

Abstract

Top lance gas injection processes are extensively used in metallurgical engineering. When the exit of the top lance is placed near the bath surface, a downward bubbling jet is generated in the bath. The flow patterns of the downward bubbling jet are classified into seven categories mainly with gas flow rate. Instability phenomena of the bubbling jet appear when the gas flow rate is higher than a certain critical value. The phenomena are strongly dependent on the penetration depth of the bubbling jet into the bath, and hence, an empirical relation is proposed for the penetration depth as a function of the gas flow rate, nozzle diameter and vessel diameter.