Noise Characteristics in Spool Valve with V-notches

Experimental investigations on the noise characteristics in spool valve with v-notches are conducted in this paper. Cavitation noise with frequency peak forms when the flow state changes form single phase turbulent to cavitating. The peak frequency decreases with the increase of the flowrate. On the other hand, jet flow develops intensely from the notches. Self-sustained flow oscillation produces whistling noise with pure tones, which is much more powerful than the cavitation noise. The pure tone frequency jumps with the outlet pressure, in each jump range, which has good monotonicity with the outlet pressure.