In this paper, the cavitation performance and corresponding pressure pulsation, noise and vibration induced by the choked cavitating flow in a Venturi reactor are investigated experimentally under different cavitation conditions by using high-speed camera and high frequency sensors. Based on the instantaneous continuous cavitation images, the Proper Orthogonal Decomposition (POD), a tool to analyze the large-scale cavitation flow structure, is applied to investigate the choked cavitating flow dynamics. The POD results show that two mechanisms, re-entrant jet flow mechanism and shock wave mechanism, govern the shedding and collapse of cavitation cloud at different pressure ratios. These mechanisms contribute to the variation of pressure pulsation, noise and vibration at different pressure ratios. The pressure pulsation spectrum behaves differently in various cavitation regions induced by the choked cavitating flow. Due to the existence of low pressure in re-entrant region, the influence of high frequency fluctuation on pressure pulsation caused by re-entrant flow is small. Moreover, with the increase of pressure ratio, the induced noise and vibration intensity decreases gradually, then increases and reaches a maximum value. Finally, it drops to a low and stable level. Despite different inlet pressures, the intensity of cavitation noise and vibration reaches the maximum value at the same pressure ratio. Specifically, the FFT analysis of noise and vibration signals indicates that low frequency component prevails at small pressure ratios owing to the re-entrant jet mechanism, while high frequency component prevails at large pressure ratios owing to the shock wave mechanism. The relationship between the choked cavitation dynamics and the induced pressure pulsation, noise and vibration in the Venturi reactor is highlighted. The results can provide guidance for the optimal operation condition of the Venturi reactor for cavitation applications such as water treatment.

本文利用高速摄像头和高频传感器，在不同的空化条件下，通过实验研究了文丘里管反应器中的空化性能以及相应的压力脉动，噪声和振动。基于瞬时连续的空化图像，采用Proper Orthogonal Decomposition（POD）分析大型空化流结构的工具，以研究the化的空化流动力学。POD结果表明，在不同的压力比下，空洞云的脱落和塌陷控制着两种机制，即折返射流和冲击波机制。这些机制会导致不同压力比下压力脉动，噪声和振动的变化。压力脉动谱在由阻塞的空化流引起的各个空化区域中表现不同。由于折返区域中存在低压，因此高频波动对折返流引起的压力脉动的影响很小。而且，随着压力比的增加，感应噪声和振动强度逐渐减小，然后增加并达到最大值。最后，它下降到一个较低的稳定水平。尽管入口压力不同，但在相同的压力比下，空化噪声和振动的强度仍达到最大值。具体而言，噪声和振动信号的FFT分析表明，由于重入射流机制，低频分量在小压力比下占主导地位，而高频成分由于冲击波机制而在较大的压力比下占主导地位。文丘里管反应器中的气蚀现象与诱导的压力脉动，噪声和振动之间的关系得到了强调。结果可为文丘里反应器在气蚀应用（例如水处理）中的最佳运行条件提供指导。