Numerical Simulation and Mechanism Investigations of Cavitating Noise Around a Two-Dimension Valve Pilot Stage

The two-dimensional valve integrates the pilot stage and the power stage on one spool, which makes it easy to achieve a fast valve operation and a high frequency response. It has the advantages of simple structure, stable performance and high power to weight ratio. In this paper, the fluid flow in the pilot stage of a 2D valve is analyzed by computational fluid dynamics, and the influence of cavitation on the flow field in the valve is the main study objective. The result shows that the throttling action of the valve port forms a high-speed jet in the chute area of the valve sleeve, and a large area of cavitation cavitation is generated at the same time. The velocity vortex and cavitation work together to intensify the pulsation of the fluid in the valve and become the main source of the noise. In the 2D valve pilot stage, the sound pressure level at the back of the chute of the valve sleeve reaches 175dB, and the maximum sound pressure level at the middle and outlet reaches 168dB. The sound pressure level at the back and middle of the chute decreases first and then increases, and the sound pressure level at the outlet of the chute decreases slowly. In the range of 0 - 5000Hz, the noise energy is concentrated in the low frequency band of less than 1000Hz, showing typical cavitation noise characteristics. The numerical result is favorable with the experimental result.