转子—支承系统典型故障非线性动力特性分析与实验研究

发布时间：2018-12-15 10:01

【摘要】：旋转机械在国民经济各部门中发挥着非常重要的作用。随着对旋转机械更高转速、更高效率的追求,其核心部分转子系统的工作环境越来越严峻,因此,转子故障时常发生。这就需要对故障转子的动力学特性、振动特征以及诊断技术进行深入研究,以期为工程设计和故障诊断提供充分的指导。本文采用有限元方法,进行故障转子动力学特性与故障诊断技术研究,主要研究内容如下： 1.对滑动轴承—转子系统动力特性进行研究,分析系统参数对其动力特性的影响。结果表明：偏心量、润滑油动力粘度、轴承长径比以及轴承间隙对系统均有较大影响；提高润滑油动力粘度和减小滑动轴承间隙可提高系统稳定性。 2.建立考虑弹性静子的碰摩系统动力学模型,研究弹性静子与非弹性静子碰摩的异同。结果表明：静子质量越大、碰摩刚度越大,转静耦合作用越明显。当静子质量远大于转子质量时,转静碰摩可简化为非弹性静子状态；若静子质量与转子质量相近,在研究转静碰摩时必须考虑两者之间的耦合作用。 3.对裂纹转子系统动力特性进行研究,分析系统参数对其动力特性的影响。结果表明：裂纹在转轴中心或在低转速、小偏心量的情况下,更容易被识别,裂纹的产生对系统失稳转速和失稳类型影响不大。 4.对碰摩、裂纹转子进行故障诊断研究,提出将时域波形、FFT频谱图及Hilbert-Huang时频谱应用于转子故障诊断中。系统地研究裂纹转子、碰摩转子以及两故障耦合转子在不同转速下的振动特征,得出：裂纹转子在临界转速的1/5、1/3和1/2运行时,频谱图中会出现明显的5X、3X和2X谐波共振；Hilbert-Huang时频谱能更准确有效地辨别碰摩,甚至是频谱分析无法诊断的轻微碰摩。 5.对故障转子进行实验研究,实验结果很好地验证了数值方法得出的结论,并为转子的故障诊断提供参考依据。 6.对高速离心压气机实验中出现的转静碰摩故障进行分析,找出故障原因,并提出改进方案；改进后,实验件顺利推到全转速运行,成功验证故障分析及改进方案的合理性。
[Abstract]:Rotating machinery plays a very important role in various departments of national economy. With the pursuit of higher rotating speed and higher efficiency of rotating machinery, the working environment of rotor system is becoming more and more severe. Therefore, rotor faults often occur. In order to provide sufficient guidance for engineering design and fault diagnosis, it is necessary to deeply study the dynamic characteristics, vibration characteristics and diagnosis technology of the fault rotor. In this paper, the dynamic characteristics and fault diagnosis technology of rotor are studied by finite element method. The main contents are as follows: 1. The dynamic characteristics of sliding bearing-rotor system are studied and the influence of system parameters on its dynamic characteristics is analyzed. The results show that eccentricity, dynamic viscosity of lubricating oil, ratio of length to diameter of bearing and bearing clearance have great influence on the system, and increasing the dynamic viscosity of lubricating oil and reducing the clearance of sliding bearing can improve the stability of the system. 2. The dynamic model of rub-impact system considering elastic statics is established, and the similarities and differences between elastic statics and inelastic statics are studied. The results show that the greater the mass of the stator, the greater the impact stiffness and the more obvious the coupling effect is. When the mass of the stator is much larger than the mass of the rotor, the rotational static impact can be simplified as an inelastic static state, and if the mass of the stator is close to that of the rotor, the coupling action between the two must be considered in the study of rotational static impact. 3. The dynamic characteristics of cracked rotor system are studied and the influence of system parameters on its dynamic characteristics is analyzed. The results show that the crack is easier to be identified in the center of the shaft or in the case of low rotational speed and small eccentricity, and the occurrence of the crack has little effect on the instability speed and type of the system. 4. The fault diagnosis of rub-impact and cracked rotor is studied. Time domain waveform, FFT spectrum and Hilbert-Huang time spectrum are applied to rotor fault diagnosis. The vibration characteristics of cracked rotor, rub-impact rotor and coupled rotor with two faults at different speeds are systematically studied. It is concluded that when the cracked rotor runs at a critical speed of 1 / 5 / 1 / 3 and 1 / 2 of critical speed, there will be obvious 5X in the spectrum diagram. 3X and 2X harmonic resonance; The spectrum of Hilbert-Huang can identify rub-impact more accurately and effectively, even slightly rub-impact which can not be diagnosed by spectrum analysis. 5. The experimental results of the fault rotor verify the conclusion of the numerical method and provide a reference for the fault diagnosis of the rotor. 6. This paper analyzes the rotating static rub-impact fault in the experiment of high-speed centrifugal compressor, finds out the cause of the fault, and puts forward the improved scheme. After the improvement, the test piece is successfully pushed to the full rotational speed operation, and the rationality of the fault analysis and the improved scheme is verified successfully.
【学位授予单位】：中国科学院研究生院（工程热物理研究所）
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH165.3

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