Research On Micro-vibration Mechanism Of Space Mechanical Refrigerator

The cryocoolers are widely used in space science projects for the cooling of detectors or telescopes.There are multiple moving parts inside the cryocooler,Therefore,it is difficult to avoid the generation of micro vibration,The micro vibration of cryocooler able to greatly affect the quality of satellite imaging,so it is particularly important to analyze the micro-vibration of cryocoolers.This article mainly researches and analyzes the basic composition and classification of space mechanical cryocoolers,and concludes that the micro vibration generated by the compressor is more significant.In order to investigate the vibration characteristics of compressors,a model with two degrees of freedom is developed for the dual-opposed linear compressor.The nonlinear gas spring force in compression space and the force results from gas flow in the seal clearance are taken into account.Then,Runge-Kutta methods is adopted to solve the differential equations numerically,and the generation of micro vibration by the gap type seal was studied.Impact.The mechanism of micro-vibration of the compressor of a certain type of cryocooler is studied:(1)The drive frequency spectrum of the piston response at the same driving frequency.As the driving frequency increases,the amplitude of the high-frequency harmonics continues to increase.When the driving frequency reaches around 54 Hz,the harmonic component of the double frequency is even much larger than that of the fundamental frequency.(2)Besides,vibration exports result from asymmetry of mass,damping and stiffness are analyzed.Simulation results show that the compressor's vibration force and torque output are a series of harmonics based on the linear motor drive frequency.As the asymmetry of mass,damping,and stiffness increases,the amplitude of each harmonic of the vibration force increases.(3)The ANSYS finite element analysis was performed on the stiffness of the compressor's flexible leaf spring.It can be seen that due to the different number of spiral arms,the stiffness and harmonious response analysis of the leaf spring are different.The micro-vibration force test platform was used to conduct experimental research on the micro-vibration of this type of cryocooler compressor.The research results show that at 54 Hz and its multiplier frequency of the cryocooler,the amplitude of the vibration disturbance force and torque of the cryocooler is much higher than that of the cryocooler.The amplitude of other multipliers.And as the power of the cryocooler increases,the amplitude of the disturbance force and the torque moment increase.The test results are consistent with the numerical analysis results,which can provide a strong basis for the design of the cryocooler.