| With the promotion of "carbon neutral" policy in the world,the full premixed combustion system with natural gas as energy source has attracted more and more attention.In this paper,the aerodynamic noise problem of gas proportional valve-J1000(GPV-J1000)in full premixed combustion system is studied systematically.Based on the CFD theory,the flow sound analog numerical simulation method was used to carry out the research.The turbulence and aero-noise characteristics of GPV-J1000 are analyzed.Through the sound source analysis,the main sound location of aerodynamic noise is determined.The optimal noise reduction scheme suitable for GPV-J1000 is proposed.It provides theoretical basis and technical support for the design and optimization of GPV-J1000.Firstly,the flow channel model and mesh model of GPV-J1000 are established by using finite element analysis software.The pressure,velocity and eddy current intensity in steady and transient flow fields are numerically simulated and analyzed.Based on the experimental test platform of full premixed combustion system,the variable opening flow rate of GPV-J1000 is tested experimentally.The outlet flow obtained from numerical simulation and experimental test is compared.The reliability of the numerical simulation results is verified.It lays a foundation for simulation of aero-noise to provide accurate turbulent parameters.Secondly,the finite element and infinite element sound fields of GPV-J1000 are numerically simulated by using Lighthill flow-sound analogy method.The acoustic numerical model is established.The monitors and directivitys are set.Based on the sound source,the velocity of the transient simulated in time domain are transformed into the aero-noise source in frequency domain according to the Fourier rule.The spectral characteristics,acoustic directivity and pressure level distribution of pneumatic noise of GPV-J1000 are analyzed.By changing the simulation condition of GPV-J1000,the influence of inlet and outlet pressure difference and opening on aerodynamic noise was studied respectively.Finally,the active noise reduction technology is used to study the noise reduction optimization of GPV-J1000.By means of sound source optimization noise reduction method,the influence of five throttling components structure of primary/secondary solenoid valve seat,primary/secondary valve port and spool upper disc on eddy current intensity and aerodynamic noise sound pressure level was analyzed.The flow characteristics and aerodynamic noise reduction effects of the above five throttling components before and after optimization are studied respectively.Finally,an overall optimization and noise reduction scheme for GPV-J1000 is proposed. |
