中文摘要：

为研究阀口高速流动中的旋涡空化机理及其与噪声特性的关系，运用高速摄像、噪声频谱分析等手段对典型阀口孔隙节流处的流场及流动现象进行分析。利用高速摄像机在微距模式下对阀口流场进行观测，最高拍摄速度达120000幅／s。研究发现空化的产生与流动分离受背压的影响最为明显，进口压力对气穴形态及噪声影响次之；孔口较深时，不同流动参数下气穴初生的位置始终位于节流边与孔壁相交的锐缘区附近，随着阀口开度的变化，初生位置稍有变化。频谱分析同时表明，气穴的形态和尺度是影响噪声的最重要因素之一。

英文摘要：

To study the cavitation mechanics and its relationship with noise characteristics of the valve-port high-speed flow, high-speed photography and noise spcctrum analysis are applied to investigate the flow area and the related phenomenon inside the throttling area of valves. The observation is taken under macroshot-model and the frame rate of high-speed camera can reach 120 000 frames/s. Both the experimental and the numerical results reveal that the cavitation inception and flow separation have close relationship with the pressure distribution in the valve. As the secondary influencing factor, the change of inlet-pressure also affcets the characteristics of cavitation and noise. To deep orifice, the position of cavitation inception is invariably near the sharp-cdged area, where the throttling-edge crosses the side-wall of the orifice, and the inception position slightly changes with the change of valve opening. Spectrum analysis indicates that the size and shape of cavitations are also the most important factors which affcet the noise.