Investigation on Cavitation Behavior and Noise in Hydraulic Valves

Cavitations inside hydraulic valves were investigated by using high-speed camera technology and noise spectrum analyzing method. The bubble flow’s morphological and flowing characteristics were converted into numerical information by the employment of image process, which made the two-phase flow easily identifiable. Based on this, cavitation’s distribution and shape characteristics were revealed. Combined with cavitation noise spectrum analyzing, it was found that the shedding process of cavitation had similar high frequency properties with cavitation noise spectrums. Typical noise curves of cavitations were obtained, and the second peak levels were found in low cavitation number conditions. In addition, it assumed that, the shedding frequencies played a good reflection to cavitation noise while using cavitation numbers as the only variable.