Analysis of flow patterns in bubble and slurry bubble columns based on local heat transfer measurements

Flow patterns in two-phase (G-L) and three-phase (G-L-S) bubble columns are investigated based on local time-averaged heat transfer coefficients. The experiments are conducted in a 0.28 m diameter Plexiglas column in air-water and air-water-glass beads (35 mum) systems over superficial gas velocity range 0.05-0.3 m/s and slurry concentration range 0-40 vol.%. The heat transfer measurements are made with a specially designed probe which provided local heat transfer coefficients. The measured heat transfer data are analyzed to illustrate the effects of gas velocities and slurry concentrations on flow patterns in different regions of the column. The heat transfer measurements at different axial and radial positions and for different probe orientations provided further insights into liquid circulation patterns in the column. (C) 2002 Elsevier Science B.V. All rights reserved.