1.School of Energy and Environmental Engineering，Hebei University of Technology，Tianjin 300401，China;2． School of
Mechanical，Electronic and Control Engineering，BeijingJiaotong University，Beijing 100044，China
Abstract: Bubbles play an important role in life and industrial equipment． The breakup of bubbles shows
specific acoustic characteristics．Studying its acoustic characteristics can effectively reveal the essence of bubble
breakup and provide theoretical basis for engineering applications such as gas-liquid two-phase flow condition
monitoring and fluid equipment condition diagnosis．The acoustic characteristics of suspended bubbles breaking
in free space were investigated by experimental methods．The acoustic characteristic curves of bubble breaking
under different bubble characteristics were discussed，and the parameters such as characteristic frequency and
characteristic sound pressure level were obtained．The results show that the sound pressure signal of bubble
breaking presents large positive amplitude and small negative amplitude in time domain，and obvious
characteristic frequency and sound pressure level in frequency domain．Both liquid film thickness and bubble
size have obvious effects on the acoustic characteristics of bubble rupture，while viscosity has little effect．This
investigation provides a theoretical basis for the acoustic law of bubble breaking and its engineering
application，which is expected to promote the development of experimental teaching in the field of aeroac-
oustics．
