【作者】 庞新宇；

【导师】 杨兆建；

【作者基本信息】 太原理工大学 ， 机械设计及理论， 2011， 博士

【摘要】 随着汽轮发电机组等大型设备的日益细长化和复杂化,转子的支承点逐渐增多,对转子系统的状态监测和故障诊断也提出了更高的要求。多支承转子系统中轴承载荷是影响轴系稳定性的重要因素,同时轴承载荷的变化又与转子以及支承的振动存在耦合效应。单纯通过振动诊断技术可以诊断轴系失稳后产生的自激振动,但对于多支承转子系统自激振动的振源无法识别,这就给设备的维修和调整带来了巨大的困难。本文以大型汽轮发电机组的核心部件——多支承转子系统为研究对象,重点研究了轴承载荷变化与系统振动的耦合特性,研究结果一方面丰富了转子系统的振动诊断技术,另一方面为多支承转子系统自激振动振源的识别奠定了基础。本文通过理论推导,提出了轴承径向位置(水平方向和垂直方向)的识别模型。首先通过集中质量得到多支承转子系统的简化模型,在此基础上利用传递矩阵求出静态和动态下轴承载荷的分配计算公式。其次研究了轴承径向位置变化和轴承载荷变化对各支承轴承载荷的影响,并得到敏感度矩阵。最后利用敏感度矩阵建立了轴承位置和轴承载荷的识别模型。研究了试验台中轴承载荷工况监测的实现。轴承载荷的实时监测是轴系运行状况最直接最有效的监测手段,但由于安装的限制,使得轴承载荷的现场工况监测存在难度。为了研究轴承载荷与振动的耦合关系,本文对多支承转子试验台的轴承载荷工况监测进行了研究,分析了轴承载荷动态测量的可能性,提出利用间接测量法实现对轴承载荷的动态测量。介绍了课题组设计的某轴承载荷传感器；通过标定实验、回归分析,得到其静态特性性能指标；针对动态特性分别进行了采样分析、虚拟实验和有限元分析；重点研究了传感器的安装对转子系统动力学的影响。最后通过多支承转子试验台进行了实验验证。提出了轴承载荷变化对多支承转子系统振动的耦合效应。针对轴承位置改变和扭矩扰动两种干扰源下轴承载荷的变化进行了动力学分析,研究了各支承点之间振动的传递性,建立了轴承载荷与转子系统的耦合振动模型,并通过龙格库塔法进行了数值分析。利用ANSYS软件对八支承转子系统进行了建模,计算了该系统的临界转速,针对柔性和刚性两种转子系统轴承径向位置变化与各支承点的振动特性进行了动力学分析与仿真,并得到各支承点的轴心轨迹特征,进一步提出利用轴心轨迹对轴承径向位置进行模糊识别的方法。建立了八支承转子系统试验台,对轴承径向位置变化和扭矩扰动进行了模拟试验,得到不同支承处的轴承载荷值、振动特性以及轴心轨迹图,利用试验结果对轴承径向位置的识别和耦合特性进行了实验验证。更多还原

【Abstract】 As the turbine-generator unit and other large equipment were increasingly slenderized and more complex, the support points of rotor are increasing. The rotor system condition monitoring and fault diagnosis is also putting forward higher requirements. Bearing load in the multi-support rotor system is an important factor that affects the stability of the axis, while the change in bearing load has the coupling effect on the vibration of the supports of rotor. Vibration diagnostic techniques can diagnose the self-excited vibration results from the axis vibration instability, but for the self-excited vibration sources of multi-support rotor aren’t recognized. That brings great difficulties in the repairing and adjustment of the equipment. This paper’s research object is a large turbine generator’s core component, multi-support rotor system. It focuses on the coupling characteristics between the bearing load changes and system vibration. On the one hand, these results enrich the rotor system vibration diagnostic techniques, on the other hand they provide a foundation for the recognition of the self-excited vibration sources of the multi-support rotor system.In this paper, it proposed the recognition model of the bearing radial position (horizontal and vertical) through the theoretical analysis. Firstly, it had a simplified model of the multi-support rotor system by lumped mass. On the base of this, the static and dynamic bearing load distribution formula are obtained through the transfer matrix. Secondly, it got the sensitivity matrix through the study of the impact of the support bearing loads between the change of the location of the bearings and the bearing load. Finally, it established the identification model of the bearing location and the bearing load by using the sensitivity matrix.This paper studied how implemented the bearing load condition monitoring in the test. Real-time monitoring of the bearing load is the most direct and effective means of monitoring for axis running condition. However, due to the installation constraints, it had the difficulties in the on-site monitoring of the bearing load condition. To study the coupling relationship between the bearing load and vibration in the multi-support rotor system, we studied the real-time monitoring of the bearing load condition and analyzed the possibilities of the dynamic measuring of the bearing load. In the paper, it proposed the indirect measurement of achieving the dynamic measurement of the bearing load. This paper described a bearing load sensor. To get the static characteristics performance index, we did a lot of calibrating experiments and the regression analysis. To get the dynamics characteristics performance index, we carried out the sampling analysis, virtual experiments and finite element analysis. We focused on the rotor system dynamics effects of the installation of the sensor. Finally, it had the experimental verification on the multi-support rotor test.The paper proposed the coupling effects on the rotor system vibration because of the change of multi-support bearing load. It carried on the dynamic analysis of the bearing load changes under the two kinds of the interference. That is the case of the bearing’s location change and torque disturbance. That examined the transfer of vibration between the support points and established a coupling vibration model between the bearing load and the rotor system and did the numerical analysis through the Runge-Kutta methods. That did the modeling system of the8support rotors with the help of the ANSYS software and calculated the critical speed of the system. For the two sides of position changes of the flexible and rigid rotor system and the vibration characteristics of the support points, we did a dynamic analysis and simulation and got the axis orbit features of all the support points. In addition, it proposed the fuzzy recognition method of the radial position of the bearing by using the axis orbit trajectories.8support rotor system test bed was established and radial position changes and torque disturbances of the bearing was simulated. That got the different values of bearing load, vibration characteristics and the axis orbit trajectories. In the end that did a lot of experimental verification of the identification of the bearing’s radial location and coupling characteristics by the test results.更多还原