Noise Properties in Spool Valves with Cavitating Flow

Investigations on cavitation noise in non-circular opening spool valves have been conducted in this paper. The cavitation noise is used as a good sign to cavitation process because of its similar trends in different valves. Cavitation inception is judged from the overall sound levels and the noise spectrums, which show good similarity. However, the characteristics of the cavitation's distribution seem discrepant in valves with different grooves. In the valves with V-grooves, cavitation always grows up by the throttling edges, and in the valves with U-grooves, two grow-up states exist. Moreover, the flow-choking phenomenon has been found in the cases of test valves.