Study On Vibration Mechanism And Application Of Aeroengine Rotor Non-concentricity

In aeronautics field,the one or several connecting surfaces of the engine are slippage in the working state due to thermal deformation,axial force increase,assembly error and rub-impact,which will cause the high pressure rotor non-concentricity,and ultimately lead to exceed the standard of the aero-engine vibration.However,there are few models for the analysis and research of the aero-engine rotor non-concentricity.In this paper,the vibration mechanism and its application of aeroengine rotor non-concentricity are studied.The main research work is embodied in:(1)The vibration mechanism of the rotor non-concentricity is studied.The coupled dynamic model of the rotor-rolling bearing is established,and the effects of rotor bending and mass eccentricity on the vibration of the rotor-roller bearing tester are simulated.The results show that: when the rotor bending and the mass eccentricity are considered separately,the fault features of both are basically the same.But when totor bending and the mass eccentricity are considered simultaneously,the amplitude of the displacement at the turntable is not the sum of the displacement amplitudes in the case of two separate fault considerations,and when the mass eccentricity is in a certain eccentric phase angle,the vibration amplitude of the tester will decrease.(2)A new testing method of the rotor bending is proposed,and the test system of rotor bending was developed to realize the on-line test of the bending degree of the rotor and the dynamic display of the bending state at the same time.Then the eddy current displacement sensor is used to measure the bending vector of the different cross section of the rotor.The bending vectors of the cross section centroids with respect to the rotation center in the same absolute coordinate are obtained.Finally,the rotor with initial bending was tested by dial gauge method.Through comparison and analysis,the results of two kinds of measurement methods are basically coincident with each other,which fully shows the correctness of the proposed method of measuring the bending of the rotor by eddy current displacement sensor.(3)In connection with double-rotor areo-engine,the vibration model of the aero-engine with high pressure rotor non-concentricity faults is established,and the influence of the different phase and different size of the rotor non-concentricity on the vibration of the whole rotor is simulated and analyzed.The results show that in the actual control of the aero-engine rotor non-concentricity,the rotor non-concentricity phases of the each sections of the rotor are different as far as possible.Finally,the problem of excessive vibration of the whole engine during the running from the idle to the maximum speed is analyzed by using the high pressure rotor non-concentricity faults(axial bending).The results show that the high pressure rotor non-concentricity faults(axial bending)is the dominant fault.