Research On Simulation Analysis Of Scroll Compressor Rotor System Under Variable Speed

As the third-generation compressor,the scroll compressor is a new type of high-efficiency fluid machinery.Because of its excellent thermodynamic performance and unique structure and motion law,it is widely used in the refrigeration industry,vehicle air-conditioning,compressed gas and petrochemical industries.Multiple areas.With the gradual improvement in the performance of the scroll compressor,the working speed also increases.Therefore,the requirements for the stability and balance of the transmission system are getting higher and higher,and its operation directly affects the performance of the scroll compressor.Therefore,it is necessary to analyze and study the balance and dynamic characteristics of the rotor system as the main structure of the transmission system.This paper takes the rotor system of a horizontal natural gas scroll compressor as the research object.Through a combination of theory and simulation,the rotor system consisting of orbiting scroll,main bearing,auxiliary bearing,eccentric crankshaft,balance iron and pulley Perform dynamic analysis.First of all,this thesis analyzes the gas force on the rotor system based on the basic structure and working principle of the scroll compressor,and establishes a mathematical expression.Then it analyzes the overall force of the main components of the rotor system,the orbiting scroll and the eccentric crankshaft,and establishes the force and moment balance equations.Secondly,according to the geometric parameters of the scroll compressor rotor system,the Solidworks software is used to model it in three dimensions.Then the finite element model of the rotor system is obtained based on the ANSYS Workbench software,and the modal analysis is performed to obtain the first six natural frequencies of the rotor system and the corresponding mode shape.The critical speed of the rotor system is further calculated.The results show that the There is no critical speed point in the speed range of 0～6000rpm,and the machine runs smoothly.By expanding the speed range,the critical speed is 45687.6rpm.Then,on the basis of modal analysis,the steady-state unbalanced harmonic response analysis of the rotor system is carried out,and the unbalanced masses are respectively 0.0032kg,0.008kg,0.02kg,0.05kg and 0.125kg.The amplitude-frequency response diagram of the deformation with frequency under the balanced load and the corresponding maximum deformation cloud diagram of the rotor system.After analysis,it is found that as the unbalanced mass becomes larger,the amount of deformation of the rotor system also increases,and the vibration of the rotor system There is a positive correlation between the amplitude and the unbalanced mass.Finally,the transient unbalance response analysis method is used to analyze the problem of the rotor system running under variable speed conditions（especially at startup）,and the centrifugal force change caused by the unbalanced mass is analyzed.By simulating the rotor system,the speed will change from 0rpm within 5s during startup and acceleration.Under the condition of unbalanced force at 6000 rpm,the overall deformation of the rotor system is obtained over time,and the deformation cloud diagram at the maximum deformation is extracted.The analysis results show that the maximum deformation occurs at the working speed of the rotor system from 0to 6000 rpm.At the outer edge of the balance iron,the amount of deformation is1.541×10^-4m.According to the standard vibration evaluation level ISO-10816 for rotating machinery,the rotor system has a good vibration state and runs smoothly.