Noise Characteristics Analysis And Noise Reduction Optimization Of Oil-free Piston Air Compressor

In recent years,with the rapid development of new energy vehicles in China,the noise caused by fuel engines in previous cars no longer exists,resulting in the prominent noise generated by the operation of air compressors.As a commonly used type of air compressor for electric vehicles,oil-free air compressors have the advantages of safety,environmental protection,and efficiency;However,due to limitations in weight and volume,as well as design defects,the exhaust pipeline may generate aerodynamic noise during operation,while the vibration of the rotor system may cause shell radiation noise.Therefore,how to reduce the aerodynamic noise and vibration radiation noise of oil-free air compressors is of great significance for improving the competitiveness of air compressor products.This article will focus on the specific model of the enterprise,using a combination of experimental testing,theoretical calculation,and simulation simulation to analyze the noise characteristics and optimize noise reduction of the oil-free piston air compressor.Firstly,noise and vibration response tests were conducted on this type of air compressor using semi anechoic laboratory and LMS testing software.Then,based on experimental test data,perform spectral analysis and observe the typical frequency bands of noise and vibration respectively;Then the coherence analysis of noise and vibration signal is carried out by MATLAB software to distinguish the typical frequency of aerodynamic noise.Subsequently,an air compressor air circuit model was established in Solid Works,and preliminary evaluation and analysis of air circuit noise were conducted using fluid analysis software STAR-CCM+.Combined with modal acoustic analysis,the key sensitive structural parameters of pipeline noise were determined.Then,sensitivity analysis and orthogonal experimental methods were used to optimize the key parameters of the pipeline.Further simulation shows that the broadband noise of the gas path has been reduced by 8.1d B.Furthermore,to study the vibration radiation noise problem of air compressors,firstly,theoretical modeling of the main shaft transmission system of the air compressor was conducted,and the dynamic balance calculation analysis of the main shaft inertia force was carried out.Under the constraint of maintaining the integrity of the main body,the balance mass block was optimized with the counterweight plate as the core;Then the multi rigid body dynamic analysis of the main shaft system was carried out using ADAMS software to verify the mechanical improvement performance before and after the optimization.On the basis of reducing the dynamic force of the main bearing,its time domain curve was extracted to provide a load spectrum for subsequent research.Finally,the vibration radiation noise mainly radiates outward from the air compressor casing as the carrier.Therefore,first establish the three-dimensional model of the whole air compressor casing,apply the dynamic load of the main bearing extracted previously to the corresponding position,and study its vibration response characteristics through ANSYS Workbench.At the same time,conduct modal analysis of the casing based on actual operating conditions.Import the surface node vibration velocity of dynamic response into the multi-functional simulation platform Simcenter 3D to complete the prediction of radiated noise of the air compressor body.By combining modal analysis and radiated noise prediction results,targeted optimization is carried out on the weak links of the casing to enhance the stiffness of key structures of the casing.Further analysis of the optimization results shows that after optimization,the total sound power of the vibration sound radiation surface of the entire machine is reduced by 6.7d B.Through the research in this article,noise reduction optimization was carried out on a certain type of air compressor from two aspects: air path noise and mechanical radiation noise.The relevant research methods and methods can provide reference for noise reduction of the same type of air compressor.