FLOW CHARACTERISTICS NEAR THE NOZZLE IN A BUBBLE COLUMN WITH SIMULTANEOUS GAS-LIQUID INJECTION

Gas holdup, bubble rising velocity and bubble size were measured by an opticalfiber probe near a nozzle in a bubble column with simultaneous gas-liquid injection. A jet-like spouting stream was formed near the nozzle, and the height of the jet was not affected by the diameter of the nozzle. Bubbles were formed at the side wall and the top of the jet, and they dispersed radially with increasing axial position. When the axial position was greater than 88 cm from the nozzle, the radial distribution of gas holdup became uniform regardless of axial position. The radial dispersion and the bubble diameter depended on the nozzle diameter, and the effects of simultaneous gas-liquid injection on the bubble formation were similar to those of an increase of pressure. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.