Numerical Simulation of Mixing Characteristics in a Top-Bottom Combined Blowing Converter Based on Bubble Characteristics and Vortex Distribution

A validated Large Eddy Simulation (LES)-Volume of Fluid (VOF) coupled model is established to investigate the mixing characteristics in a combined top-bottom blowing converter. It is found that after the bottom-blowing flow rate increases to 0.86 N m3/h, the bubble formation mode transitions from single-bubble mode to double-bubble mode. As the bottom-blowing flow rate increases, the Reynolds (Re) and Weber number (We) of the bubble swarm increase, the proportion of low-velocity bubbles gradually decreases, and the bubble swarm becomes more uniform in diameter distribution. Due to the instability of the impact crater, the inclination angle of the central plume decreases as the bottom-blowing flow rate increases, and the subgrid scale (SGS) turbulent dissipation exhibits larger fluctuations over time at low flow rates. Vortex entropy exhibits a quasi-periodic variation similar to crater depth. The correlation between vortex entropy and mixing time indicates that vortex entropy can effectively predict the mixing rate.