Heat Transfer Characteristics in a Large-Scale Bubble Column Operating in a Semi – Batch Mode

Abstract

Time-averaged local heat transfer coefficient profiles were studied in a 0.45m bubble column using air-water system. The effect of the superficial gas velocity andaxial locations (Z/D) on the heat transfer coefficient and its radial (r/R) profiles wereinvestigated in bubble column. Significant differences were observed between heattransfer coefficients in the axial directions viz. in the bulk flow region (Z/D=4.8)higher than in the distributor region (Z/D=0.28) by 14% -22% for increasing thesuperficial gas velocity from 0.05-0.45 m/s. The heat transfer coefficients increasewith superficial gas velocities and the values in the center of the column were 9–13%greater than those near the wall region .The characteristics of bulk flow region arelarge variation in radial direction and little in axial direction for the values of heattransfer coefficients.

Keywords

• bubble columns
• large
• scale
• heat transfer coefficient
• axial location
• radial profile