Signals of sound pressure oscillations during vapor condensation and transition of condensation regimes were investigated using a high-speed video camera and a hydrophone. Results indicate three different condensation regimes with the increase of subcooling and vapor injection rates

which are referred to as bubble oscillation regime

transition regime and capillary wave regime. In addition

two waveforms occur in the detected signals

of which sources are vapor bubble split-up and collapse. The kurtosis of the signals presents step changes

which is close to the transformation threshold of condensation regimes. The peak at frequency of 150—300 Hz appears in spectra in all condensation regimes

which may be resulted from the periodic variation in vapor volume. The peaks with frequency higher than 7000 Hz appear only in transition and capillary wave regimes and may be the resultant of the high-frequency oscillation in pressure caused by sudden collapse of vapor bubbles. The bubble collapse frequency increases with the increase of subcooling and vapor injection rates and is close to the frequency of the first peak in spectra with an error within ±20%.