高速转子故障物理特性及全矢动平衡技术研究

发布时间：2018-08-17 11:15

【摘要】：对于旋转机械来说,不平衡是其最主要的激振源,导致许多自激振动的产生。历年来,动平衡技术始终是学术界研究和关注的焦点。随着旋转机械容量不断增大,机械结构的不断复杂,转速进一步提高,传统的转子平衡领域理论和技术不能很好地适应工业生产的发展要求,主要表现在:多次启机试重进行平衡,既浪费时间,又增加平衡费用。在一些特定的情况下,现有动平衡理论计算出来的配重有很大偏差,平衡精度很低,甚至导致平衡失败。在这一背景下,本文从失衡转子故障物理机理入手,对不平衡响应规律进行探讨,重点分析了失衡转子在支撑各向异性和非线性因素下不平衡响应的特性。为了提高现场平衡的效率和精度,本文利用信息融合的全矢谱理论和有关技术,提出了新的转子动平衡方法,实验验证了新方法的有效性和工程应用价值。本文的主要研究成果与结论如下:1)研究了失衡转子的故障物理特性。传统平衡方法均是建立在线性假设和转子各向同性的基础上,而实际上转子各向异性和非线性因素是导致平衡精度不佳的主要原因。因此本文重点研究了失衡转子在各向异性和非线性基础上不平衡响应的规律。结论表明:在线性模型假设下,各向异性支撑单圆盘转子对于不同的失衡量其不平衡响应为一组同心椭圆,其方位角维持不变,椭圆的偏心率保持不变,其长/短半轴随不平衡量的大小线性变化,椭圆的初始相位角随失衡量的相位的变化而变化;而在非线性情况下,转子的不平衡响应椭圆的偏心率和方位角均随失衡量的大小的变化而变化。2)提出一种新的动平衡方法—全矢动平衡方法(FVDB)。该方法基于全矢谱的截面信息融合方法定义了全矢不平衡响应(FVUR),全矢不平衡响应以工频主振矢作为不平衡响应的幅值,以椭圆的相位角为其相位,结合影响系数法或振型平衡法进行现场的平衡;理论推导证明:全矢不平衡响应的灵敏度高于单传感器响应的灵敏度,说明全矢动平衡方法精度优于传统方法;实验结果表明:全矢动平衡方法平衡效果优于传统方法,提高了平衡的效率和精度,具有良好的工程应用价值。3)结合进动分解理论,提出一种的新的平衡方法—进动分解平衡法(PDDB)。提出PDDB方法是源于以下思路:复杂柔性转子在组合故障作用下,转子轨迹中正反进动分量呈现不同比值,但总体来说,正进动分量与平衡故障相关度更大,反进动分量往往预示机器存在平衡以外的其他故障,即不平衡量与正进动响应矢量是成正比的。PDDB方法的指导思想为:采用正进动不平衡响应,即FPUR作为平衡目标结合传统的影响系数法或振型平衡法来完成平衡。通过数值模拟和实验研究证明:PDDB方法与传统方法相兼容,在实际平衡中更能克服平衡故障以外的干扰。相对于全矢动平衡方法FVDB来说,进动分解平衡方法PDDB更适用于复杂转子系统、特别是除不平衡外还存在其他复合故障的场合。4)提出了基于相位差频谱校正的微速差双转子现场平衡方法。结合微速差双转子系统结构对“拍振”信号的产生原因进行分析,结果表明:由于内外转子转速接近,非整周期信号采集导致频谱泄露的产生,即内、外转子不平衡响应中至少一个是失真的,这是导致平衡效果不佳的原因。在此基础上,提出了基于相位差频谱校正的内外转子不平衡响应分量提取方法,对失真的转子响应的幅值和相位进行校正,并给出相位差校正平衡法的微速差双转子平衡方法,通过仿真和实验证明:该方法可显著提高微速差双转子的平衡精度。现场平衡实例充分证明了该方法的优越性。5)开发了包含以上新平衡方法功能的系列仪器。基于以上三种新的动平衡方法,采用嵌入式技术,开发了便携式现场动平衡仪。并就全矢不平衡响应的振动信号及键相采集等关键技术进行了探讨,给出了全矢不平衡响应,进动分解算法以及频谱校正分离方法的算法流程,实现了新的平衡方法的工程化应用。工程应用实例表明了本文研究成果的正确性和开发产品的实用性。
[Abstract]:For rotating machinery, unbalance is the main exciting source, which leads to many self-excited vibrations. Over the years, dynamic balancing technology has always been the focus of academic research and attention. To meet the development requirements of industrial production, it is mainly manifested in the following aspects: balancing the weights of several startup tests, which wastes time and increases the cost of balancing. In some specific cases, the weights calculated by the existing dynamic balancing theory have great deviations, the accuracy of balancing is very low, and even lead to the failure of balancing. In order to improve the efficiency and accuracy of field balancing, a new method of rotor dynamic balancing is proposed based on the full vector spectrum theory of information fusion and related technologies. The main results and conclusions of this paper are as follows: 1) The fault physical characteristics of unbalanced rotor are studied. The traditional balancing methods are based on the linear assumption and the rotor isotropy. In fact, the rotor anisotropy and nonlinear factors lead to poor balancing accuracy. The main reason is that the unbalance response of the unbalanced rotor on the anisotropic and nonlinear basis is studied in this paper. The results show that the unbalance response of the single disk rotor with anisotropic support is a set of concentric ellipses with constant azimuth and eccentricity under the assumption of linear model. The initial phase angle of the ellipse varies with the phase of the unbalance, while the eccentricity and azimuth of the unbalanced response ellipse vary with the unbalance. 2) A new dynamic balance method, full vector dynamic leveling, is proposed. Full vector unbalanced response (FVUR) is defined based on the cross-section information fusion method of full vector spectrum. Full vector unbalanced response takes the main frequency vector as the amplitude of unbalanced response, the phase angle of ellipse as its phase, and combined with the influence coefficient method or mode balance method, the field balance is proved theoretically. The sensitivity of balancing response is higher than that of single sensor, which shows that the precision of full vector dynamic balancing method is better than that of traditional method. The experimental results show that the balancing effect of full vector dynamic balancing method is better than that of traditional method, and the efficiency and precision of balancing are improved. It has good engineering application value. 3) Combining with precession decomposition theory, a new method is proposed. Progressive decomposition balance method (PDDB) is proposed. The PDDB method is derived from the following ideas: under the combined fault of complex flexible rotor, the positive and negative precession components in the rotor trajectory show different ratios, but generally speaking, the positive precession components are more related to the balancing fault, and the negative precession components often indicate the existence of a machine other than the balancing fault. The guiding principle of PDDB method is to adopt positive precession unbalanced response, i.e. FPUR as the balance target and combine the traditional influence coefficient method or mode balance method to balance. The precession decomposition balancing method PDDB is more suitable for complex rotor systems than the full vector dynamic balancing method FVDB, especially when there are other complex faults besides unbalance. The reason of "beat" signal is analyzed in the structure of speed difference double rotor system. The results show that the frequency spectrum leakage is caused by non-integral period signal acquisition because of the approximate speed between inner rotor and outer rotor. In other words, at least one of the unbalanced response between inner rotor and outer rotor is distorted, which is the reason of poor balance effect. The amplitude and phase of the distorted rotor response are corrected by the method of extracting the unbalanced response components of the inner and outer rotor with phase difference spectrum correction. The method of balancing micro-speed difference rotor with phase difference correction balance method is given. The simulation and experimental results show that the method can significantly improve the balancing accuracy of micro-speed difference rotor. The advantages of this method are fully proved. 5) A series of instruments including the functions of the new balancing methods are developed. Based on the above three new balancing methods, a portable on-site dynamic balancing instrument is developed by using embedded technology. The algorithm flow of unbalanced response, precession decomposition algorithm and spectrum correction separation method has realized the engineering application of the new balance method.
【学位授予单位】：郑州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TH113.25

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