Hydrodynamics and mass transfer studies of a confined plunging jet

A confined plunging jet may be used as an energy efficient means of entraining a gas into a liquid for mass transfer. The application of such a jet as a wastewater oxygenator has been described. A literature survey of both the theoretical and experimental reports relevant to the hydrodynamics and mass transfer characteristics of both unconfined and confined plunging liquid jets systems, has been presented. The objective of the present study is to develop a better understanding of the confined plunging liquid jets, as a contribution towards establishing its future use as an oxygenator, especially in wastewater treatment. The effects of the three main operating variables investigated are the jet Reynolds number ReN, jet length to nozzle inside diameter ratio Lj/DN and the nozzle inside diameter DN. The effect of the downcomer size Dc on the hydrodynamics properties include the gas entrainment rates was also examined. Desirable effects on the hydrodynamics, with increasing operating variables have been obtained. [Continues.]