Study On Aerodynamic Noise And Structure Optimization Of Outer Cage Throttle Valve

In the high-pressure natural gas extraction process,the external cage sleeve type throttle valve,as a key device used to balance the high pressure at the wellhead and the pressure-bearing of the pipeline manifold,is often required to have a high degree of safety and efficiency.However,in the field of gas extraction,the high noise generated by the gas flow in a small and compact space,high flow rate,high pressure difference,high temperature and other complex working conditions will not only reduce the accuracy of the equipment and restrict the safe and efficient extraction of gas wells,but also affect the health of the staff.In this paper,an external cage sleeve type throttle valve for a gas well is used as the research object to carry out noise reduction optimization research,and the corresponding conclusions are obtained,which provide theoretical support for the throttle valve noise reduction research.The main research contents and results are as follow:(1)Based on the research status of throttle valves at home and abroad,a compressible numerical model is established on the basis of fluid mechanics theory.Fluent software is used to simulate the steady-state flow field,and the influence rule of different opening and pressure ratios on the flow field in the valve is obtained,and the initial flow field information is provided for the transient simulation.Large eddy simulation(LES)is used to analyze the time-varying characteristics of flow field information.Based on the feedbacks of the parameters of steady and transient flow fields,the fundamental reasons of aerodynamic noise generated by throttle valve are analyzed from the perspectives of vorticity,shock wave and jet potential core,and the main noise components of valve aerodynamic noise are obtained.(2)The structural modal analysis of the throttle valve and manifold integrated system is carried out by Abaqus software,and the dominant structural modal which is easy to induce the structural resonance of the system is found out.Virtual Lab acoustic software is used to analyze the acoustic modes of throttle valve acoustic resonator and find out the dominant acoustic modes that contribute the most to the resonant noise radiation of the acoustic cavity.(3)The structural modal analysis of the throttle valve and manifold integrated system is carried out by Abaqus software,and the dominant structural modal which is easy to induce the structural resonance of the system is found out.Virtual Lab acoustic software is used to analyze the acoustic modes of throttle valve acoustic resonator and find out the dominant acoustic modes that contribute the most to the resonant noise radiation of the acoustic cavity.(4)The high noise of the throttle valve is related to the motion state of the medium inside the valve in the flow field,and the flow state of the working medium is subject to the flow path structure of the throttle valve.Based on the research results of the flow characteristics and aerodynamic noise characteristics of the throttle valve,an improvement scheme is proposed for the structure of the outer cage type throttle valve to change the overall flow state of the fluid medium in the valve and reduce the pressure gradient.The generation of shock noise is suppressed and the intensity of turbulence noise and jet noise is reduced.(5)The response surface method is used to optimize the parameters of the improved device,and the quadratic polynomial fitting equation of the response index and the design parameters is obtained.The accuracy of the fitting model is verified by variance analysis.Finally,the optimal solution is found in the sample design space,and the maximum aerodynamic noise of the optimized new outer cage sleeve throttle valve is reduced by13.1dB,which achieved a good noise reduction effect.