航空发动机双转子系统的模态及其表达方法

Modal characteristics and their expression method for aeroengine dual-rotor system

为解决双转子系统模态特征无法清晰表达,高、低压转子主激励的幅频特性在振动信号中不易识别的问题,以典型的发动机双转子系统为对象,建立有限元模型,分析双转子系统模态特性。基于进动分析理论,建立双转子系统正、反进动模态判断方法。建立了双转子自振频率和临界转速的“两面三维”表达方法,以及双转子不平衡响应的“三面三维”表达方法,并应用于双转子实验器。理论分析与实验结果表明:双转子自振频率和临界转速“两面三维”表达方法能将自振频率与高、低压转子转速和共同工作线清晰地关联在一起;双转子不平衡响应“三面三维”表达方法将双转子的振动与转速、转向和转速控制律清晰地描绘在一起,便于理解和分析转子的振动特性。该研究结果对于分析和表征双转子系统的动力学特性有重要的支撑作用。

Here,to solve problems of modal characteristics of dual-rotor system being unable to clearly express,and amplitude-frequency characteristics of main excitation of high-pressure rotor and low-pressure one being not easy to identify in vibration signals,taking a typical engine dual-rotor system as the study object,a finite element model was established to analyze modal characteristics of dual-rotor system.Based on the whirl analysis theory,forward and reverse whirl mode judgment method of double-rotor system was established.The “2-plane 3-dimension” expression method for natural vibration frequencies and critical speeds of double-rotor and the “3-plane 3-dimension” expression method for unbalanced response of double-rotor were established and applied in double-rotor tester.Theoretical analysis and experimental results showed that the “2-plane 3-dimension” expression method of double-rotor natural frequencies and critical speeds can clearly correlate natural frequencies of double-rotor with high-pressure rotor rotating speed and low-pressure rotor one and their common working line;the “3-plane 3-dimension” expression method of double-rotor unbalance response can clearly depict double-rotor vibration together with its rotating speed,rotating direction and rotating speed control law for conveniently understanding and analyzing rotors’ vibration characteristics;the study results can play an important supporting role in analyzing and characterizing dynamic characteristics of double-rotor system.