Experimental study of gas-induced liquid-flow structures in bubble columns

The computer-automated radioactive-particle tracking (CARPT) technique is used to investigate liquid recirculation and turbulence in bubble columns. Experiments are conducted in air-water bubble columns of different sizes, with various gas distributors, and operated over a range of superficial gas velocities. This study covers gas-liquid flows front the bubbly regime to the churn turbulent regime. The time-averaged spatial flow structure, axial liquid velocity profiles, Reynolds shear stress, and turbulence intensities profiles are analyzed for different columns and flow conditions. Supplemental, experiments, using the hot-probe anemometry technique, are performed at selected flow conditions, and the results are compared with the corresponding ones front CARPT measurements. The Reynolds stress determined by CARPT was compared with that obtained by hot-film anemometry in an independent investigation by Menzel ct al. (1990).