Bubble coalescence in viscous liquids

✍ Scribed by J.R. Crabtree; J. Bridgwater

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 944 KB
• Volume: 26
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(71)83045-2

✦ Synopsis

When a gas is bubbled into a viscous liquid, coalescence of the bubbles occurs. This in turn influences the bubble-induced liquid flow and the mass transfer rate, matters of considerable practical importance. Experiments have been conducted on the relative motion of vertically aligned bubble pairs, each having volumes from 10 to 40 cm3, in a 67 per cent wt solution of sucrose in water. The Reynolds numbers encountered were 40-90. It was demonstrated that bubbles up to 70 cm apart initially, coalesced, even when the difference in the infinite fluid rise velocities of single bubbles would suggest that coalescence is impossible. Although more detailed information upon wake structure and the motion of bubbles in such wakes is required before a fuU explanation is possible, a theoretical treatment relying on an asymptotic wake velocity profile provides a general explanation of the phenomenon.