Bubble Formation and Surface Sloshing in the TSL Flow with a Viscous Liquid

Due to the ever-increasing importance of the top-submerged lance (TSL) process in metal recycling and slag valorization, considerable effort have been devoted to studying TSL flow characteristics. In this work, the bubble formation and surface sloshing in a TSL flow with a viscous liquid are numerically investigated by the volume-of-fluid model coupled with large eddy simulation approach. First, the numerical model is validated by high-resolution particle imaging velocimetry (HR-PIV) experiments in both qualitative and quantitative manners. After that, the numerical model is adopted to determine the bubbling frequencies at various operational conditions. The results show that the bubbling frequency decreases with increasing gas flow rate, and it slightly depends on the lance submergence depth. Besides, a dimensionless correlation is proposed considering inertial force, viscous force and surface tension. Similar correlations are achieved for the present work and the experimental work from the literature. The agreement highlights the ability of the proposed correlation to evaluate bubbling frequency obtained at diverse conditions. In addition, the influences of gas flow rate and lance submergence depth on surface sloshing behavior are clarified. This fundamental work gives insights into the TSL flow physics, the understanding of which can aid in TSL process control and optimization.