THE TEMPORAL RISE BEHAVIOR OF OZONE-CONTAINING GAS BUBBLES IN AQUEOUS SOLUTION

摘要

A high-speed micro video was used to observe the temporal rise behavior of ozone-containing gas bubbles in aqueous solution. Results indicate that the presence of low ozone concentrations (less than 20 mg/l in this research) in the gas bubbles has minimal impact on the bubble rise in aqueous solutions. The shape of bubbles shifted from spherical to be more like ellipsoidal during the rise course along the column. The average diameter of bubbles at X-axis was markedly increased after the bubbles left the diffuser because the gas pressure inside the bubbles was not balanced with surrounding water pressure. The rise of bubbles was accelerated to reach a pseudo terminal velocity of about 28 cm/sec. The gas-liquid interfacial areas were determined to be ranging from 3.3 to 8.9 m~(-1) for gas flow rate ranging from 145 to 656 ml/min. The dimensionless drag coefficient, C_D , was calculated to be about 0.12 based on the pseudo terminal velocity, and was believed to be markedly affected by the variation of bubble shape during the rise course. The shape of bubbles formed in aqueous solution with the presence of SDS (sodium dodecylsulfate), a commonly used anionic surfactant, was kept spherical rising along the column. The addition of SDS significantly raised the calculated interfacial area of o-zone mass transfer.