带套齿连接结构的转子系统振动稳定性实验研究

Experimental Study on Vibration Stability of Rotor System with Spline Connection Structure

关键词:  航空发动机  套齿连接结构  转子系统  振动稳定性  内摩擦

Key words:  Aero-engine  Spline connection structure  Rotor system  Vibration instability  Internal friction

摘要:

为了研究带套齿连接结构的转子系统振动稳定性，推导了套齿连接结构的内摩擦力表达式，由此求解了转子系统振动失稳的条件。设计并搭建了带柔性和刚性两种不同套齿连接结构的实验转子系统。实验研究了带不同套齿连接结构的转子系统振动的稳定性。实验发现，带柔性套齿连接结构的转子系统易于发生由内、外套齿齿面间内摩擦所引起的振动失稳。失稳的特征是转子振动中出现较突出的次谐波分量，次谐波频率为转子系统的第一阶自振频率。次谐波出现的门槛转速略高于转子系统的第一阶临界转速。不对中度的增大对次谐波具有激励作用，促使转子失稳加剧，锁紧螺母拧紧力矩增大对失稳有抑制作用。带刚性套齿连接结构的转子系统越过了工作转速范围内的第三阶临界转速，未出现失稳现象。在第一阶模态与第二阶模态处分别进行了300s的“共振”实验，实验过程中未出现次谐波振动分量，转子保持稳定。结果表明，带刚性套齿连接结构转子的稳定性高于带柔性套齿连接结构的转子。

Abstract:

In order to study the vibration stability of the rotor system with spline connection structure， the internal friction force expression of the spline connection structure was derived and the vibration instability conditions of the rotor system were solved. The experimental rotor system with two different spline connections including rigidity and flexibility spline was designed and built. The vibration stability of rotor system with different spline connection structure was studied experimentally. It was found in the experiment that the vibration instability of the rotor system with flexible spline connection structure was easy to occur due to internal friction between the tooth surfaces of the inner and outer. Characteristic of instability was appearing prominent sub-harmonic components in rotor vibration and the sub-harmonic frequency was the first natural frequency of the rotor system. The threshold speed for the occurrence of sub-harmonics was slightly higher than the first critical speed of the rotor system. The increase of misalignment had a stimulating effect on sub-harmonics and promoted rotor instability aggravated and increased tightening torque of the lock nut had an inhibitory effect on instability. The rotor system with rigid spline connection structure had crossed the third critical speed in the working speed range and there was no instability phenomenon. The "resonance" experiment was carried out for 300s in the first mode and the second mode respectively， there was no sub-harmonic vibration component during the experiment and the rotor remained stable. The results show that the stability of the rotor with rigid spline connection structure is higher than that of a rotor with flexible spline connection structure.