Study On Noise And Fatigue Life Of Reciprocating Piston Air Compressors

The reciprocating piston air compressor is a machine for increasing pressure by crank slider mechanism.By right of its unique characters of the wide pressure range and easy adaptability,its application range is growing fast.However,there are still many problems with reciprocating piston air compressors in application to industry at present:working without failures,it severes noise affecting users’physical and mental health in some degree;unbalanced inertia force produced by its internal structure crank slider mechanism is a common cause of serious body vibration and noise to some extent in normal working.The reciprocating piston mute machine has low noise and high cost.It is prone to arise fatigue failure problems after running for some time.In order to solve the above problems,the single-cylinder reciprocating piston air compressor was selected as the research object of the noise problem,and the reciprocating piston mute machine was taken as the research object of the fatigue life problem.It was analyzed using ANSYS Workbench finite element simulation and nCode fatigue simulation.The research mainly contains the following parts:(1)Noise detection experiment on reciprocating piston air compressor was performed.The single-cylinder reciprocating piston air compressor equipped with an air filter was perceived as the research object.The noise source was predicted.The four operating conditions of 0psi,60psi,90psi,and 135psi were selected for noise detection.The experimental data was analyzed to determine the frequency of the noise source,which offers some data support and provides theoretical research for subsequentstudy on noise reduction.(2)A dynamical model of the crank slider mechanism of a reciprocating piston air compressor was established.The crank slider mechanism in the reciprocating piston air compressor was taken as the kinematics analysis object to obtain the mathematical expression of the piston acceleration.The relationship which between the crank mass and the reciprocating inertial force was obtained by performing the dynamics analysis.(3)Comprehensive noise reduction measures for reciprocating piston air compressors were studied.The research was carried out on reducing vibration,avoiding resonance and vibration reduction.The relation between the crank design parmeters and the whole machine vibration was explored,the force at the main bearing of the crankcase was taken as measurement index of the whole machine vibration.The three-dimensional model of the reciprocating piston air compressor was simplified,and ANSYS Workbench was used for multiple simulation analysis.Using ANSYS Workbench,it was simulated and analyzed many times,and the data was analyzed to obtain the minimum reciprocating inertial force and the optimal amount of vibration crank design parameters.The correctness of the optimal crank parameter values,the feasibility and effectiveness of the optimized crank parameter scheme were verified by dynamics theoretical calculations.What’s more,modal analysis was used to determine the natural frequencies of the crank,connecting rod,and crankcase to ensure a large difference from the frequency of the noise source,avoid resonance phenomena,and reduce noise.Last but no least,the calculation formula of the rubber vibration isolator was performed to select a suitable rubber vibration isolator.As a result,comprehensive noise reduction measures were performed to improve the performance of the air compressor in some degree.(4)The design method on the fatigue life of the silent reciprocating piston air compressors valve plate was optimized.The silent reciprocating piston air compressors valve plate was taken as the research object.The results of the parts fatigue cycle times were obtained using ANSYS Workbench and nCode.With changing the valve plate parameters and simulation analyzing repeatedly for a number of times,it was obtained that the optimal value of the valve plate thickness is 5.34mm.It can increase the minimum lifespan from 1.126 to 1.315.It solved systematically the problem of fatigue life and improved the reliability of air compressor work to establish a fatigue life optimization model in some degree.In this thesis,the former resurrection plug air compressor was regarded as the research object.Based on using ANSYS Workbench and nCode and existing design experience,the design research was performed to reduce noise and improve life.The noise detection on the reciprocating piston air compressor was performed to find ou the frequency of the noise source and provide a theoretical basis for noise reduction;the dynamics analysis of the crank-slider mechanism was carried out to find the relationship between the impact of the crank on the inertial force,and a new design scheme for the design parameters of the crank was proposed to reduce the value of inertial force for reducing noise;the fatigue life of valve plate was predicted to replace parts reasonably and effectively and improve the utilization rate of material in some degree.This not only enriches the noise and fatigue research of reciprocating piston air compressors in industrial applications,but also provides a certain theoretical support for later research.