Effects of sloshing gas-liquid interface on dynamics of meandering bubble plumes and mixing in a shallow vessel: PIV and PLIF measurements

摘要

Gas-liquid shallow vessels are widely used in steel-making and refining processes in the steel industry. The efficiency of these processes or the quality of steel depends on the extent of gas-induced liquid-phase mixing achieved through top-blowing of oxygen and bottom-blowing of inert gases. In the present work, the effects of combined top and bottom gas injection and sloshing interface on the dynamics of gas-liquid flow, and their role in the liquid-phase mixing in a shallow vessel, that corresponds 1:6 scaled-down model of a ladle used in steel refining, are investigated. The effects of interface sloshing and top blowing on the motion of multiple meandering bubble plumes on the liquid-phase velocity distribution, recirculatory flow structures and turbulent kinetic energy are analyzed using the time-resolved Particle Image Velocimetry (PIV) measurements. Further, the role of the aforementioned parameters on the liquid-phase mixing is analyzed using the Planar Laser Induced Fluorescence (PLIF) measurements. The effects of coaxial and eccentric top blowing configuration on the liquid flow structures and mixing are also investigated. In the case of combined top and bottom gas injection, in which gas was injected very close to the interface, the liquid-phase mixing was found to be significantly faster than that of the other configurations considered in the present work, due to the formation of strong downward flow regions and higher turbulent kinetic energy provided by the top blowing. The present investigations help to understand and to quantify the effects of the different top gas injection configurations on the meandering motion of bubble plumes, liquid flow structures, turbulence and their contributions to liquid-phase mixing.