GAS HOLD-UP AND LIQUID-MIXING AT LOW AND INTERMEDIATE GAS VELOCITIES .1. AIR-WATER SYSTEM

Gas hold-up and liquid phase dispersion experiments have been carried out in a 0.06 m bubble column at varying liquid and gas velocities. The results obtained show that the coefficient of liquid mixing varies with the flow regime. The isotropic turbulence theory of Baird and Rice (Chem. Eng. J, 9 (1975) 171) was used to provide dimensionally consistent correlations for the chain bubbling, bubbly and churn turbulent flow regimes. The gas hold-up was determined to increase with gas velocity in the chain bubbling and bubbly flow regimes. The results obtained from this study also show that the Froude number represents a useful criterion for mapping flow regimes in vertical bubble columns.