单双跨油膜力转子非线性动力学特性研究

发布时间：2018-03-19 11:59

本文选题：油膜力轴承　切入点：双跨多盘转子　出处：《兰州交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：对于转子系统构成的旋转机械应用面很广泛而且常被用在一些重要而又特殊场合,所以对于转子运行的安全稳定性就十分重要。人们通过对重大转子事故的研究和分析,发现很多情况下引起转子系统运动失稳的原因是众多非线性力的作用导致的,那么想要从根本上解决问题就要从具体问题中抽象出研究对象并建立数学模型,分析在非线性力作用下转子系统的运行特征,从而得到有利于转子运行平稳的条件以及参数数据。本文分析在强非线性力油膜力、碰磨力以及离心力的作用下,转子系统动力学特性。在假设转子圆盘质量分布不均,存在偏心量以及转子轴承不对中等条件下建立了单盘油膜力轴承转子系统模型以及油膜力支撑下的双跨多盘转子系统模型,先用雷诺公式求解出油膜力大小,然后列出转子系统运动方程,通过四阶龙格库塔法编程,数值模拟计算出系统的数值解,使用分岔图、相图、庞加莱映射图以及时间历程图来阐明了转子系统参数的变化对系统解的影响,通过对它们的变化分析得到了在非线性力的影响下,选取怎样的系统参数才会使得转子发生碰磨最少,转子运行稳定。研究结论表明,对于双跨多盘油膜力转子模型,当定子刚度值增大时,除了低转速下转子运动稳定,保持不变,在其他区域都出现大量混沌概周期运动,因此选择较小的定子刚度值;对于转子刚度值的变化,当它增大时,较低和较高转速下转子系统受影响不大,中等转速下会逐渐出现大量混沌概周期区域,所以在确保足够大的抗变形能力下,选择比较小的刚度值;当圆盘质量发生变化时,低速区域受到影响较小,运动始终很稳定,中高转速区域,圆盘质量增大,运动越不稳定,所以尽量选择较小的质量值;当摩擦系数增大,对于系统的影响较小,因此选择适当大小的值,避免碰磨严重的区域;当逐渐增大圆盘阻尼值,中等转速和高转速下的转子出现概周期,复杂运动的现象明显减少,继续增大圆盘阻尼值,对转子运动稳定性的影响开始降低,因此在选取时,选一个适当偏大的圆盘阻尼值;对于轴承处质量值的变化,在低转速区域影响较小,对于中等转速区间影响较大,因此最好选择较小的轴承端质量值。通过对上述参数对系统响应的影响分析,可以有助于在转子制造和工作的过程中,选择合理稳定的结构和运行参数。
[Abstract]:The rotor system has a wide range of applications and is often used in some important and special occasions, so it is very important to the safety and stability of rotor operation. It is found that in many cases the instability of rotor system motion is caused by many nonlinear forces, so if we want to solve the problem fundamentally, we must abstract the research object from the concrete problem and establish the mathematical model. The operating characteristics of rotor system under nonlinear force are analyzed, and the conditions and parameter data are obtained, which are favorable to the smooth operation of the rotor. In this paper, the oil film force, rubbing force and centrifugal force of strong nonlinear force are analyzed. Dynamic characteristics of a rotor system. On the assumption that the mass of the rotor disk is unevenly distributed, The rotor system model of single disk oil film force bearing and the double span multi disc rotor system model supported by oil film force are established under the condition of eccentricity and the mismatch of rotor bearing. Then the equations of motion of the rotor system are listed. The numerical solution of the system is calculated by numerical simulation through the fourth order Runge-Kutta method, and the bifurcation diagram and phase diagram are used. Poincare map and time history diagram are used to illustrate the influence of rotor system parameters on the solution of the system. Through the analysis of their variations, the influence of nonlinear forces is obtained. The research results show that for the rotor model of double-span multi-disk oil film force, when the stator stiffness value increases, the rotor motion is stable except at low speed. In other regions, a large number of chaotic almost periodic motions occur, so a smaller stator stiffness value is chosen. When the rotor stiffness value increases, the rotor system will not be affected at lower and higher rotational speeds. At medium rotational speed, a large number of chaotic almost periodic regions will gradually appear, so a relatively small stiffness value is chosen to ensure sufficient anti-deformation capability. When the mass of the disk changes, the low speed region is less affected and the motion is always stable. In the region of medium and high rotational speed, the mass of the disk increases and the movement becomes more unstable, so the smaller the mass value is, the less the influence on the system is when the friction coefficient increases, so the appropriate value is chosen to avoid the serious area of rubbing. When the disk damping value increases gradually, the rotor at medium speed and high speed appears almost periodic, and the phenomenon of complex motion decreases obviously, and the effect on the stability of rotor motion begins to decrease when increasing the damping value of the disk, so when the rotor is selected, Choose an appropriate disk damping value which has less influence on the mass value of the bearing in the region of low speed and a greater influence on the range of medium speed. Therefore, it is better to select a smaller mass value of the bearing end. By analyzing the effect of the above parameters on the system response, it is helpful to select reasonable and stable structure and operation parameters in the process of manufacturing and working of the rotor.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH133;TH113

【参考文献】