Fluid flow and gas-liquid mass transfer in gas-injected vessels

Fluid flow, bubble distribution and gas-liquid mass transfer in a water model vessel with gas injection were analyzed to make clear the effect of turbulence on metallurgical reactions in ladles. Continuity equation, Navier-Stokes equation, k-ε equation and bubble-dispersion equation in axially symmetrical form were solved numerically. Calculated time-averaged liquid velocities and fluctuating velocities agreed well with the data measured by a Laser-Doppler Velocimeter. Calculated local gas-holdup distribution also agreed with the observed results. Volumetric mass-transfer coefficients were estimated in two regions in the vessel, the bubble-dispersion zone and the free surface of liquid, based on the eddy-cell model using calculated results of ε. The results were compared with the observed ones for a CO₂-water system obtained in our previous study. Estimated results gave reasonable agreement only for the bubble-dispersion region. In the case of the volumetric coefficients at the free surface, calculated results were larger than the observed ones. The reason for this disagreement was discussed based on the free surface fluctuation.