A Stacking Assembly Method For Optimizing Mass Properties Of Multistage Rotors Of Aero-engine

The development of aeroengine is the core of Aeronautical Manufacturing industry,one of benchmarks to measure the level of national equipment manufacturing,and one of the areas concerned by “Made in China 2025”.The high-speed rotation of the multistage rotors of the core engine is the power source of the aeroengine.Due to the large number of stages of rotors assembly,the small machining errors will be transmitted and amplified step by step in the assembly,which will lead to the eccentricity of the center of gravity and inertia deviation of the rotors assembly.The slight deviation of the center of gravity and moment of inertia of the assembled multi-stage rotors will lead to the vibration and the slow response of the aeroengine during high-speed rotation.Therefore,it is urgent to develop a new stacking assembly method for the multi-stage of aeroengine to suppress the error transfer process in order to optimize the mass properties.In this paper,a stacking assembly method for optimizing mass properties of multistage rotors of aeroengine is proposed.The eccentricity of the center of gravity and rotational inertia of the multi-stage rotors assembly are optimized by rotating every rotor.Through study of error transfer in assembly process,the transfer model of center of gravity and moment of inertia for the assembly is established,which can predict the center of gravity eccentricity and the moment of inertia of rotors assembly.Provide optimization simulation and assembly experiment verification.The main research contents are as follows.Firstly,the transfer model of mass properties is established.A simplified model of aeroengine machining error is established,which decomposes the machining error of the rotor’s spigot into radial positioning error and axial orientation error;Analyze the influence of machining error transmission and installation phase on the position of the center of gravity of the single stage rotor,which can realize the center of gravity coordinate transformation of single rotor;furthermore,the center of gravity transfer process of the two-stage and three-stage rotors assembly is analyzed step by step,and finally the center of gravity transfer model of multi-stage rotors assembly is realized;by simulating the two-stage and three-stage rotors assembly,the center of gravity optimization mechanism and optimization effect are studied,and the general optimization law is summarized.In the same way,the transfer model of inertia tensor of multi-stage rotors assembly is established,which has the same simulation to get the optimization mechanism and optimization effect.Secondly,the optimization of mass properties of rotors assembly based on the Monte Carlo principle.To overcome the problem of high time and cost of large-scale assembly experiment through 10000 times of random assembly simulation.At the same time,it also verifies the stability and optimization effect of the optimal assembly method in large-scale production process.The simulation results show that the average maximum gravity moment of the two、three and four rotors optimized assembly is reduced by 66.8%,73.6% and 88.8% respectively and the standard deviation is reduced by 44.7%,30.3% and 52.1% respectively,which compares to direct assembly.The average moment of inertia of the two、three and four rotors optimized assembly is reduced by 15.2%,28.0% and 74.0% respectively and the standard deviation is reduced by 4.8%,13.5% and 58.2% respectively,which compares to direct assembly.Optimized assembly methods effectively improve assembly quality.Finally,the experimental verification of the optimization model of rotors assembly mass properties is carried out.The UOI series aeroengine rotors assembly and measurement system,which is developed by Harbin Institute of Technology,is used to measure the geometric errors of the spigot of each stage of the rotor.The eccentricity of the center of gravity is calculated by measuring the unbalance of the rotors with a dynamic balancing machine,which to verify the prediction accuracy of the eccentricity of the center of gravity.The average prediction error of six groups of experiments if 14.38% when the rotors are assembled with different installation phases.The transfer model of the center of gravity of rotors assembly basically realizes the prediction of the eccentricity of the center of gravity.