Analysis of Damping Mechanism and Acoustic Attenuation Characteristics of Bubble Oscillation Driven by Sound

To study the acoustic propagation characteristics in the boiling region of steam generator, the damping mechanism of bubble oscillation in water driven by sound and the acoustic attenuation characteristics induced by bubbles under high temperature and high pressure conditions were analyzed. At the same time, based on the bubble damping theory, and combined with the linear model of acoustic propagation in bubble-containing water, the relationship between the damping and attenuation in bubble-containing water and the boundary layer thickness was derived. Results show that the bubble oscillation system is in an underdamped state at a₀=10^-6~10^-3 m and f=20~20 000 Hz. When a₀=10^-3 m and \widetilded≥0.2, an overdamped state exists in the bubble oscillation system. Under high temperature and pressure conditions, thermal damping dominates the total damping coefficient and is the main factor causing acoustic dissipation. The boundary layer thickness significantly affects the acoustic attenuation, and the acoustic attenuation coefficient increases and then decreases with the increase of \widetilded.