基于多模式超声场作用下的空泡空化机理

Cavitation mechanism of bubbles under multi-mode ultrasonic field

为构建多模式超声空化机理,研究了空泡脉动的空化行为.利用PVDF压电薄膜传感器对多模式超声场进行实时监测,获得了单频、双频和三频组合下的超声空化噪声信号,在此基础上进行傅立叶转换,得到了频域谱线,根据不同频率组合下的超声波形,推算出了相应的峰值声强和平均声强.结果表明:三频同时工作获得的噪声信号强度高于双频同时工作获得的噪声信号强度,单频获得的噪声信号强度最低;多频超声场的频谱幅值高于单频超声场的频谱幅值,频谱出现2个峰值,主要集中在低频区域;三频超声作用下获得的空间峰值声强和平均声强最大,单频超声下的峰值声强和平均声强最小.

To establish the cavitation mechanism of multi-mode ultrasound,the cavitation behaviour of bubbles was investigated. The multi-mode ultrasonic field was monitored by polyvinylidene fluoride( PVDF) sensor,and the ultrasonic cavitation noise under the combination of single,dual and triple frequencies was obtained. The fast Fourier transform was used to gain spectrum in frequency domain.Based on the ultrasonic waveforms with different frequencies, peak and average intensities were calculated. The results show that the noise intensity of triple frequency is the highest,and that of single frequency is the lowest. Spectrum amplitudes of multi-frequency are higher than that of single frequency,and two peak values of frequency spectrum mainly focus on low frequency domain. Peak and average intensities of triple frequency are the highest,and that of single frequency is the lowest.