Research On Supporting Characteristic Analysis And Dynamic Balance Method Of Rotor System

Rotor system is an important part of aero-engine.With the advancement of aerospace and defense technologies,aero-engines are increasingly developing in the direction of large thrust-to-weight ratio,large aspect ratio,high speed and high reliability.However,the vibration problem of the aero-engine rotor system has always restricted the development of aero engines.A large number of studies have shown that rotor imbalance is the main cause of vibration of the rotor system.Therefore,in order to reduce the overall vibration of the rotor system,on the one hand,according to the actual structure of the aeroengine rotor system,the critical speed and damping can be adjusted by optimizing the design of the support structure.On the other hand,the imbalance of the rotor system can be reduced by the dynamic balance method.The main research contents of this paper are as follows:(1)Based on the pseudo-kinetic model of rolling bearing,the variation of contact angle,contact deformation and contact force between the rolling element and the inner and outer rings at different speeds is analyzed.Considering the actual contact between the rolling element and the inner and outer raceways,combined with Hertz contact theory and elastic fluid lubrication theory,the comprehensive stiffness and comprehensive damping model of the rolling bearing are established.The effects of bearing working speed,radial external load,inner and outer raceway radius and number of balls on comprehensive stiffness and comprehensive damping are analyzed.(2)According to the force condition of the web-type elastic support and the theory of elastic mechanics,the formula for calculating the stiffness is deduced.Combined with the sensitivity analysis and finite element simulation of the panel structure parameters,the parameter optimization design method of the web-type elastic support structure is proposed,which is optimized according to the similar process.The parameters optimization design method of the web-type elastic support structure and the effectiveness of the two methods are verified by simulation design.(3)The simulation model of high-pressure rotor similar test-bed for aeroengine is established by finite element method,and the sensitivity of different turntables to unbalanced response is calculated.The most effective balance surface is selected according to sensitivity analysis results.The advantages and disadvantages of traditional balance methods are summarized and compared.Based on the sensitivity analysis theory,the three-circle balance method and the modal balance method are combined to propose a hybrid balance method.The traditional influence coefficient method is optimized to retain the test weight influence coefficient method,and the transient start equilibrium method is improved.Three kinds of balance methods were used for simulation and experimental verification.Based on the test results,the problems in the rotor balance process were summarized and the criteria for selecting the balance method were proposed.(4)Aiming at the problem that the vibration signal of aero-engine rotor is difficult to collect during on-site dynamic balance,the method of integrating the vibration acceleration signal into the displacement signal after denoising and detrending processing by empirical mode decomposition method is studied.The simulation and experimental verification are carried out in parallel.