GAS ENTRAINMENT BY PLUNGING LIQUID JETS

In this paper an extensive survey of the results of possibly all available experimental and theoretical studies on gas entrainment by plunging liquid jets has been presented. The following aspects of the phenomenon are thoroughly discussed: mechanisms, conditions of the onset of entrainment, amount of the entrained gas, characteristics of the resulting bubble dispersion (bubble size, depth of bubble penetration, gas holdup and bubble residence time) and mass transfer. Wherever possible, empirical correlations enabling estimation of the relevant quantities characterizing the entrainment phenomenon studied are given or recommended. Practical applications of the plunging jet aerator in waste treatment, fermentation and in the flotation industry are reviewed and its aeration (e.g. oxygenation) performance is compared with conventional aeration systems.