Experimental study of air-water two-phase jet: bubble size distribution and velocity measurements

An experimental investigation on a horizontal two-phase air-water jet has been conducted in order to develop a technique that can provide information on the interaction between the air bubbles and turbulent flow. In order to allow a measurement of the liquid phase flow field and of the bubbles size, the Particle Image Velocimetry (PIV) has been used, with the liquid phase seeded with a fluorescent tracer consisting of Rhodamine WT mixed with a commercial polyester resin. A phase discrimination algorithm has been developed and successfully used for the detection and separation of tracers and bubbles in distinct images. Three data sets have been recorded: one for a one-phase water jet and two for a two-phase water jet. The obtained results allow a valid characterization of the flow field and an estimation of the effect of the gaseous phase in the air-water jet flow. An analysis of the bubbles size and number has been also conducted and here reported.