STUDY OF BUBBLE FORMATION DYNAMICS BASED ON ASSOCIATED ACOUSTIC RADIATION

The release of gas into water can be found in many industrial applications. This process results in the formation of bubbles, and both associated bubble size distribution and bubble volume flow rate have an important impact on the designed outcomes. Research has been carried out both experimentally and theoretically, in order to explore the underlining physics of a gas-water system of dispersed bubbles. Many researchers have used acoustic techniques to study a quasi-steady bubbly plume. However, it is relative rare to study the dynamics of turbulent release of gas into water using an acoustic techniques, in which both experimental and theoretic analyses become fairly challenging. For those conditions, the widely used optical technique is no longer reliable if an experimental study is performed. However, the use of acoustic technique has been found to be a promising approach because in injection conditions, the formation of each individual bubble emits sound. In this paper, the bubble formation dynamics will be studied using acoustic techniques. The acoustic emission of the gas discharge into water will be measured accurately and the bubble formation dynamics will be modelled based on their acoustic emission. The characteristics of the bubbly plume are explored. The bubble are generated using three nozzles having internal diameters of 4 mm, 6 mm and 9 mm and the gas discharge rate is varied between 2.5 L/min to 40 L/min. It has been found that the gas discharge rate has an strong impact on the sound of bubble formation. The choice of nozzle imparts some influence on the bubble formation.