Research On Vibration Characteristic And Aerodynamic Noise Prediction Of Micro-open Spring Loaded Pressure Safety Valve

This paper is completed with the support of Gansu Province University Basic Research Business Project.Experiment in the paper is accomplished with the assistance of Gaoshan valve group Co.,Ltd in Henan.opened for venting,it is prone to problems such as severe vibration and aerodynamic noise,which will affect the operation of the field equipment and piping system,and cause damage of the hearing health of the field workers and surrounding households.At the same time,fatigue caused by vibrations also adversely affects the safety and reliability of the safety valve itself.The prediction of the emission noise of safety valves is mostly calculated by empirical formula.The accuracy and applicability of these calculation formulas lacks comparative analysis and verification,and it is difficult to provide an accurate basis for the design of the muffler after the valve.In addition,few scholars have been studied in this area,so how to accurately predict the aerodynamic noise of the safety valve in the design stage and provide a quantitative basis for the design of the noise reduction device.It's significant to improve the environmental friendliness of the safety valve.In this paper,the following studies are carried out on the calculation of the flow-induced vibration characteristics and the aerodynamic noise of the micro-open safety valve:(1)The background and significance of this research were introduced,and the research progress and current situation of flow-induced vibration research and aerodynamic noise research at home and abroad were investigated.Moreover,the necessity of the research on flow-induced vibration characteristics and aerodynamic noise prediction calculation of safety valve were put forward.(2)The working principle and discharge capacity calculation of the safety valve are summarized,and the conventional and the new structure of safety valve are investigated.Based on the fluid-solid coupling modal analysis method,the low-order modal frequency of the valve disc was calculated.And the frequency of pressure pulsation of the monitoring point in the valve is solved by unsteady flow.What's more,the natural frequency of spring is obtained by single-degree-of-freedom system analysis.Comparing the similarity of those value,the resonance of the valve trim assembly is judged.In addition,the flow-induced vibration model of the micro-open safety valve body is established,and the vibration response of the safety valve was solved.The flow-induced vibration characteristics of the inlet section,the external wall,the outlet section of under different opening heights of the safety valve were studied.(3)The acoustic transmission path and sound source type were analyze during the safety valve is opened and vented.The calculation formula existing in the world of emission noise prediction for safety valve were compared.The theory and calculation process of simulation of aerodynamic noise are studied.The valve aerodynamic noise analysis model was established and regard the unsteady pressure pulsation and velocity pulsation as the source exci tation.Based on the boundary element method,the numerical simulation of the safety valve emission noise is carried out,and the dipole and quadrupole are analyzed.Also,the influence of the source type on the contribution of the valve emission noise was studied.Weighting the dipole and quadrupole to get the total sound pressure level,and the comparison with the formula calculation to verifies the rationality of the numerical simulation.(4)According to the requirements of operational characteristics test of safety valve,the high-frequency software was developed and the selection of hardware such as DAQ module,displacement sensor and pressure sensor,and the wiring of system were completed.Simultaneously,the test procedure was designed for operational characteristics test.In addition,considering the verification of numerical simulation for vibration and acoustic,the vibration and acoustic test system of safety valve were designed,and the test device was selected,the layout of measuring points and the test procedure of vibration and noise test were completed.(5)The operational characteristics test of the micro-open safety valve was carried out,and the practicability and operability of the paper development software were verified.The vibration characteristics of the micro-open safety valve were tested and the vibration of the valve was measured.The correctness of the numerical simulation method is verified by comparing the previous calculation results.What's more,the experiment on the emission noise characteristics of the safety valve is carried out,and the sound pressure level at 1m outside the valve is measured.Comparing the previous calculation results,the accuracy and applicability of the boundary element method and the theoretical formula to calculate the prediction noise are verified.For the prediction of the noise of the micro-open safety valve,it have shown that the formulas of recommended by API 521 and VDI 2713 are less suitable for the prediction of the noise of the micro-open safety valve but the formula recommended by ISO 4126-9 and the Energy Institute guidelines are higher.Through those above researches,the numerical simulation method of safety valve emission noise prediction calculation is extended,which enriches the s tudy of flow-induced vibration and aerodynamic noise prediction of safety valve,and provides a theoretical basis for improving the stability and reliability of safety valve.