Horizontal two-phase jet behavior with an annular nozzle ejector in the water tank

Abstract

The behavior of gas–liquid two-phase jets has been extensively studied over many years, due to their fundamental importance in many multiphase systems. Understanding jet behaviors is essential for predicting many processes of practical importance. The objective of this study is to investigate horizontal air–water jet behavior with an annular nozzle ejector in a shallow water tank and to present the effect of overall jet behavior on oxygen transfer characteristics from air bubbles to water. The experimental apparatus consisted of an electric motor-pump, an annular nozzle ejector assembly, a high-speed camera unit, a circulation water tank, and measuring or controlling accessories. The images of the air–water mixed jet issuing from the ejector are analyzed qualitatively, and the dissolved oxygen concentration is measured using the clean water unsteady state technique. The horizontal mixed jet behaves like a buoyancy jet, a quasi-horizontal bubble jet, or a horizontal momentum jet owing to the momentum of the primary flow and air bubble size. It can be concluded that the higher the momentum of primary water flow and the lower the entrainment ratio, the smaller the air bubble size. The buoyancy force of the air bubble and the penetration of the mixed flow are found to be important parameters for the oxygen transfer rate owing to the contact area and time of the two phases.