Prediction of Control Valves Aerodynamic Noise Based on Pipewall Vibrations

摘要

The fluctuating pressure created by valve forces the pipewall to vibrate.In this paper,a vibration-to-sound conversion method (VSCM) used for predicting aerodynamic valve noise is proposed.To facilitate the difficulties for conversion the pipewall vibration,the conversion loss (CL) is employed to quantify relationship between the pipe internal sound pressure level and pipewall acceleration level.The analysis shows that the CL is connected with the speed of sound at downstream conditions,pipe radius,frequency factors and the thickness and conversion efficiency of the pipe.The CL needs to be improved by frequency factor in the low frequency range correspond to lower modes.The modal density is lower and the values of frequency factor are greater in lower frequency octave bands.The experiment was carried out in a pipe system with a high pressure air tank and a low pressure air tank.Compared with experimental data,all calculated values at 1/3-octave band for internal sound pressure level lie within the error band of ±5dB.Furthermore,the maximum difference between the calculated and measured total internal sound pressure level is 0.9 dB.It is concluded that the present approach should give reliable estimates of valve noise in practical situations.