多支承转子系统动力特性分析与试验研究

发布时间：2018-12-09 20:30

【摘要】：随着大型汽轮发电机组等大型旋转设备的日益细长化和复杂化,转子系统的支承点的增加,对转子系统的动力特性和状态监测与故障诊断也提出了更高的要求。本文以大型汽轮发电机组的核心部分—多支承转子系统为研究对象,首先以单跨二支承多轮盘转子为引入对象,应用邓柯莱法、传递矩阵法、有限元法对其临界转速进行了计算,并对三种方法的特点与使用范围进行了分析比较。针对转子系统中的各种参数对临界转速的影响,提出了结构参数对临界转速的敏感度概念。进而以搭建的四跨八支承多轮盘转子系统为研究对象,采用ANSYS中的旋转结构模块仿真得到临界转速并提取了临界转速的Campbell图,并分析得到系统各单跨转子与系统转子模态振型及临界转速的关系。通过对瞬态启动响应分析可知：可以通过适当提高启动加速度的方式减小转子系统通过共振区的最大振动幅值,保证其能够更加安全可靠的运行,从而延长使用寿命。通过单跨二支承单轮盘转子试验台的试验研究,获取了系统幅频特性和波德图,进而得到系统临界转速试验值。将此试验值与通过ANSYS仿真得到得临界转速结果对比分析：结果数据比较吻合,说明利用ANSYS中的旋转结构模块对转子的临界转速计算方法是可行的。搭建了四跨八支承多轮盘转子试验台中的第四跨转子并安装调试了测试系统,包括对传感器的选用与标定。对课题组自行研制的某二维轴承负荷传感器进行了静态标定试验与静动态仿真标定,可知其静动态特性较好,能够准确地对轴承负荷实施测量。由于提取轴心轨迹中的故障特征能够对转子系统进行监测与故障诊断,试验中提取了两种不同稳态转速下的轴心轨迹,通过去噪处理后与仿真获得的轴心轨迹进行比较分析,得到了轴心轨迹在不同稳态转速下的轨迹特点。
[Abstract]:With the increasing fineness and complexity of large rotating equipment such as large turbo generator sets and the increase of supporting points of rotor system, higher requirements are put forward for the dynamic characteristics, condition monitoring and fault diagnosis of rotor system. In this paper, the multi-support rotor system, which is the core part of the large turbogenerator set, is studied. Firstly, the single-span multi-disk rotor with two supports is introduced, and the Dunkelay method and the transfer matrix method are used. The critical speed is calculated by finite element method, and the characteristics and application range of the three methods are analyzed and compared. Aiming at the influence of various parameters in rotor system on critical speed, the concept of sensitivity of structural parameters to critical speed is proposed. Then, taking the four-span and eight-support multi-disk rotor system as the research object, the critical rotational speed is obtained by using the rotation structure module in ANSYS and the Campbell diagram of the critical rotational speed is extracted. The relationship between the single span rotor and the mode and critical speed of the rotor is analyzed. Through the analysis of the transient start-up response, it can be concluded that the maximum vibration amplitude of the rotor system through the resonance region can be reduced by properly increasing the starting acceleration, so as to ensure that the rotor system can operate more safely and reliably, thus prolonging the service life. The amplitude and frequency characteristics of the system and the wave diagram are obtained through the experimental study of a single span and two support single wheel rotor test rig, and then the critical rotational speed test values of the system are obtained. The experimental results are compared with the results obtained by ANSYS simulation. The results are in good agreement with each other, which indicates that it is feasible to calculate the critical speed of rotor by using the rotating structure module in ANSYS. The fourth span rotor of the four-span eight-support multi-wheel rotor test rig is built and the test system is installed and debugged including the selection and calibration of the sensor. The static calibration test and static and dynamic simulation calibration of a two-dimensional bearing load sensor developed by our research group show that the static and dynamic characteristics of the sensor are good and can accurately measure the bearing load. Because the fault characteristics of the rotor system can be monitored and diagnosed by extracting the fault characteristics of the shaft center trajectory, two kinds of shaft center trajectories under different steady speed are extracted in the experiment, and the results are compared with those obtained by simulation after de-noising processing. The characteristics of the axis locus under different steady speed are obtained.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH113

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