Assembly Unbalance Prediction And Optimization Of Aeroengine Rotor

The aero-engine rotor mainly adopts the connection form of multi-stage discs and disc drums,which has the characteristics of large size and many stages.Assembly is an important part of the aero engine manufacturing process and a key link that directly affects the performance of the whole machine.If the unbalanced amount of assembly cannot meet the actual demand,large mechanical vibrations will be caused during the work,which will seriously affect the working performance of the aero engine and directly affect the service life of the aero engine.Therefore,it is very important in ensuring the quality of assembly and controlling the vibration of the whole machine to study the transformation mechanism of the unbalance of the rotor during the assembly process,and make reasonable adjustments to the problem of the unbalance exceeding the limit during the assembly process of the rotor.In response to the above problems,this paper establishes a rotor assembly unbalance prediction model,verifies the accuracy of the model through experiments,and develops related software,and optimizes based on the prediction model to reduce the initial unbalance of the rotor assembly.The main research contents of this paper are as follows:(1)The influence of factors such as the unbalance of the rotor part itself,the assembly position and attitude accuracy,the assembly direction,the position of the rotation axis and the blade assembly on the rotor assembly unbalance is analyzed.And the method of fitting plane and fitting circle is used to analyze the inclination of the end face and the eccentricity error of the spigot.(2)Using the method of homogeneous coordinate transformation,after considering the influence of the change of assembly phase and the position of the rotation axis,the space position and posture of each single piece and assembly are calculated.Combined with the calculation method of static and even unbalance,and the influence of blade assembly and parts’unbalance,the unbalanced mass moment generated at the correction surface and the overall static and even unbalance of the rotor are comprehensively calculated.Establish a predictive model of rotor assembly unbalance.It realizes the function of accurately predicting the initial static and even unbalance of the rotor through conditions such as weight and runout data.(3)Test the parameters such as the morphological runout data and unbalance of the high-voltage simulated rotor through experiments,and compare them with the predicted results of the model.Among them,the maximum distance error of the center of gravity of each part is0.00269mm,and the direction error is within 25 degrees.For the prediction of the overall static and even unbalance of the rotor,the errors are 47.8g·mm and 208227g·mm~2,respectively,and the directional error does not exceed 30 degrees,which proves the accuracy of the model prediction.At the same time,related forecasting software was developed based on python.(4)Based on the prediction model,the genetic algorithm is used to optimize the assembly unbalance.Taking the assembly direction as the design variable,the dual-objective optimization was carried out with the initial static and even unbalance of the rotor assembly as the goal.The static unbalance was reduced to 1.16%,and the even unbalance was reduced to3.29%.The optimization was compared with the exhaustive optimization method to prove its efficiency and accuracy.And combined with the distribution range of the center of gravity,the three-objective optimization is carried out.As a result,the distribution of the center of gravity is reduced to 14.29%while effectively reducing the amount of static and even unbalance.At the same time,the arrangement sequence of the blades was optimized,and the unbalance was reduced to 0.024%.Various optimizations can provide guidance for the actual assembly process and have certain engineering significance.