Aerodynamic Noise Analysis of Cut-Off Valve During Opening Process Under High-Pressure Conditions

Abstract Cut-off valves under high-pressure conditions are used in aerospace industries; they can quickly cut off the liquid supply in hydraulic systems, and are of great significance in ensuring the safe and reliable operation of the whole system. However, due to the high-pressure conditions, the flow velocity of the fluid will increase when crossing the throttling region inside the valve, resulting in the generation of noise and threatening the entire system. This paper takes the common check cut-off valve as an example, based on the Ffowcs Williams and Hawkings (FW-H) sound analogy theory. The opening process of the cut-off valve under real working conditions is analyzed. The opening process is defined in three phases: initial opening state (20% opening), continuous opening state (60% opening), and full opening state (100% opening). The internal flow of the cut-off valve is researched, the distribution of the noise inside and outside of the cut-off valve is analyzed through the opening process, and the mechanism of the noise generation is studied. Based on the results of the noise analysis, the optimization of geometry is proposed. By reducing the taper of the valve core, the fluid flow is more even, so as to achieve noise reduction. Finally, the noise reduction performance of the optimized geometry is validated. The results show that the noise increases gradually during valve opening. For the symmetry geometry, the noise distribution is also symmetrical. At low frequency, the noise shows obvious characteristics of a dipole sound source. The noise has broadband characteristics. The original geometry has a maximum noise of 50 dBA at the monitoring point, and the optimized geometry can reduce noise by about 20%. This work can be used for the noise reduction design of cut-off valves such as check valves under high-pressure conditions.