Acoustic noise spectra were studied for the first time in overheated water using sonohydrothermal reactor operating at 20 kHz ultrasound in the temperature range from 25 to 200°C at the autogenic pressure of 1-14 bar. The obtained results highlighted a dominating role of stable cavitation during ultrasonic treatment of hot water. Heating of sonicated water results in the formation of large number of nonlinearly oscillating bubbles synchronous with the driving frequency. At 200°C, the acoustic spectra also display strong subharmonic and multiple ultraharmonic bands. Moreover, cavitation bubbles formed at 200°C exhibit chaotic and random motions. It has been shown that the addition of TiO₂ nanoparticles to hydrothermal water heated at 200°C allows to eliminate subharmonic/ultraharmonic bands and stochastic oscillations as well. This effect was assigned to Pickering-like bubble stabilization due to the particle accumulation at the bubble surface.

使用在20 kHz超声波，温度范围为25至200°C，自生压力为1-14 bar的超声波水热反应器，在过热水中首次研究了声噪声谱。获得的结果突出了在热水超声处理过程中稳定气蚀的主要作用。超声水的加热导致大量与驱动频率同步的非线性振荡气泡的形成。在200°C时，声谱还显示出强次谐波和多个超谐波频带。而且，在200℃下形成的空化气泡表现出混沌运动和随机运动。已经表明，TiO _2的添加纳米粒子在加热到200°C的热水中可以消除次谐波/超谐波带以及随机振荡。由于颗粒在气泡表面的堆积，这种效果被赋予类似于Pickering的气泡稳定作用。