Numerical investigation of an oscillating gas bubble in an ultrasonic field

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The discovery of acoustic cavitation phenomenon is an important role in the design of a wide range of devices handling liquids and it has led to a renewed interest in the bubble dynamics in a sound field. In this study, the nonlinear behaviour of individual gas bubble in liquid under the action of ultrasound fields has been analysed, and simulated results of formation and collapse of a bubble have been provided. The characterization of acoustic cavitation bubbles under the influence of periodic pressure field, e.g., the motion of the bubble surface, pressure, temperature and density fields inside the bubble have been investigated and the results are compared with experimental data. The numerically calculated results reveal that the assumption of polytropic approximation inside the bubble predicts that a radius-time curve does not fit to the observed data. Also, the results indicate that the pressure gradient and the heat transfer inside the bubble and across the bubble surface play a major role to predict the extreme conditions associated with the bubble collapse.