1、Rotor Rub转子摩擦,Rotor Rub & the Types转子摩擦与类型,Rotor rub occurs when the rotating parts of a machine contact stationary parts and can be catastrophic, depending on specifically which parts contact one another, the material construction of each, rotational speed-induced friction, structural rigidity of b
2、oth the rotating and stationary parts and the impact velocity itself. Technical papers have classified two major Type 1- Partial Rub, and Type 2 - Full Annular Rub. 当机器的旋转部件接触到静止部件时，就会产生转子摩擦，其严重性取决于哪些部件互相接触、这些部件的材料组成、引起摩擦的转动速度、旋转与静止部件的结构硬度、以及冲击速度本身。技术上将摩擦分成两个主要类型 类型1 - 局部摩擦 类型2 - 全摩擦,Rub Events摩擦事件,
3、CATASTROPHIC RUB EVENTS严重摩擦事件Journal Contacting Bearing Babbitt轴接触轴承的巴氏合金Rotor Contacting Stator in Electric Motor电机转子接触定子Impeller Vanes Contacting Diffuser Vanes叶轮叶片接触涡壳Turbine Blades Contacting Diffuser Vanes涡轮叶片接触涡壳,Rub Events摩擦事件,LESS CATASTROPHIC RUB EVENTS轻微摩擦事件Shaft Rubbing a Seal轴摩擦密封Couplin
4、g Guard Rubbing a Shaft联轴节网罩摩擦轴Belt Rubbing Belt Guard皮带摩擦皮带网罩Fan Blades Contacting Shroud风机叶片接触导叶,General Rotor Rub Characteristics转子摩擦的一般特征,1. When rub occurs, it can actually change the stiffness of the rotor which will therefore change the rotor natural frequency during the rub event. 当发生摩擦时，转子的
5、刚度会改变，并因此在摩擦中改变转子的固有频率2. The impact can cause local wear and deformation depending on the angle of attack and impact velocity. 这种碰撞会导致局部磨损和变形，这取决于碰撞的角度和冲击速度,General Rotor Rub Characteristics转子摩擦的一般特征,3. Not only can high forces be generated due to impact, but also high torques which can almost insta
6、ntaneously affect electrical characteristics, sometimes causing a significant increase in amperage. 碰撞不仅会产生大的作用力，还会产生高扭矩，并立刻影响到电气特征，有时会导致电流的增大4. When rub occurs, friction will oppose rotation. This high friction force can even cause a backwards whirling motion known as “backward precession”. 当发生摩擦时，
7、摩擦会对抗轴的旋转。这个大摩擦力甚至会产生向后的涡动，即“反进动”,General Rotor Rub Characteristics转子摩擦的一般特征,5. A Partial Rub usually precedes a Full Annular Rub. 局部摩擦通常先于全摩擦,General Rotor Rub Characteristics转子摩擦的一般特征,6. Waterfall plots (also called Cascades) are especially helpful in diagnosing radial rubs. 瀑布图（也称作水落图）在诊断径向摩擦时特别有
8、帮助7. Shaft orbit displays are also very helpful in diagnosing rubs. 轴心轨迹图在诊断摩擦时也非常有帮助,Partial Rub局部摩擦,1 Partial rubs will generate noticeable subsynchronous vibration (vibration below 1X RPM) 局部摩擦会产生明显的次同步振动（低于1X RPM的振动）2. If the subsynchronous vibration is caused by partial rub, it will normally sh
9、ow integer subharmonics (1/2X or 1/3X or 1/4X, etc.). 如果次同步振动是由部分摩擦引起的，通常会显示整数倍的次谐波(1/2X or 1/3X or 1/4X, etc.).3. Several different integer subharmonics can simultaneously occur when a light rub with lower radial force occurs. 当发生较低径向力的轻微摩擦时，会同时产生几个不同整数分之一的次谐波,Partial Rub局部摩擦,4. Often, when a heavi
10、er radial force partial rub occurs, only one subharmonic is present -predominantly, 1/2X RPM will remain. 通常在发生较大径向力局部摩擦时，只有一个主要的次谐波族存在，通常是1/2X RPM谐波。5. If sharp impacts occur, multiples of these subharmonic frequencies can also appear (.5X, 1X, 1.5X, 2X, 2.5X, etc.) as well as high frequency resona
11、nt response. 若发生强烈碰撞，也会出现多倍数的次谐波频率(.5X, 1X, 1.5X, 2X, 2.5X, etc.) 和高频率共振响应6. During a partial rub, the response is highly directional which results in horizontal and vertical phase difference of subsynchronous vibrations approaching 180 between horizontal and vertical. 局部摩擦的响应是方向性很强的，这会导致次同步振动的水平与垂直
12、相位差接近180,Full Annular Rub全摩擦,1. A full annular rub is characterized by a backward precession at 1X RPM corresponding to the unbalance in the system which can lead to forward precession at the natural frequency of the rotor/contact surface system. 全摩擦的特征就是1X RPM 的反进动。而不平衡会产生正进动，它在转子/接触表面系统的固有频率下发生。2.
13、 Another type of full annular rub is dominated by the response at 1X RPM along with some running speed harmonics at somewhat lower amplitudes. 另一种全摩擦以1X RPM 的响应为主，并伴有一些较低幅值的转速谐波,Full Annular Rub全摩擦,3. Since friction remains continually throughout a full annular rub, it will often introduce nonlinearities generating many running speed harmonics as well. 由于全摩擦中磨擦连续不断，因此会产生非线性响应，即产生很多转速谐波4. The vibration amplitude which will result in a full annular rub depends on clearances and damping of the system. 全摩擦的振动幅值取决于轴承间隙与系统阻尼,Typical Spectrum & Waveform of Rotor Rub 转子摩擦的典型频谱与波形,
