CFD-Based Cavitation Research and Structure Optimization of Relief Valve for Noise Reduction

The cavitation flow of the cartridge pilot-operated relief valve’s main valve port was numerically simulated and studied using Computational Fluid Dynamics (CFD) in our research, and the relief valve structure was modified to decrease cavitation noise. These findings indicate that cavitation in the relief valve occurs primarily downstream of the main valve port and is linked to the wall. The cavitation generation is influenced by the jet at the valve port. The closer the high-speed jet at the valve port is to the valve’s inner wall, the more readily cavitation occurs. Conversely, less cavitation is observed. This paper reports the effects of the forms and parameters of the main port structure on the jet angle and morphology of cavitation. The annular groove structure of the spool has a considerable influence on the cavitation attached to the spool and the valve sleeve wall, whereas the outlet position of the relief valve mostly affects the intensity of cavitation near the valve sleeve wall. Based on this, an optimized structure of the relief valve was designed, with which the maximum vapor volume fraction and total vapor volume of the cavitation flow were considerably decreased for various inlet pressures and spool openings. The experimental results show that, following optimization, the noise of the relief valve drops dramatically, confirming that optimizing the structure has a beneficial impact on decreasing cavitation noise.