高速透平膨胀制冷机转子振动特性实验研究

发布时间：2018-07-17 03:32

【摘要】：随着旋转机械向着高转速、轻型化、柔性发展,以气体轴承作为转子支承部件的轴承-转子系统在高速透平得到越来越广泛的应用。本文基于高速透平制冷机实验台,实验研究了气体静压轴承润滑支承下高速转子的振动特性与稳定性。主要有:1.介绍了转子-轴承系统有限元基础理论,并对高速透平制冷机转子建立划分出轴段、轮盘以及轴承等单元的有限元模型。利用ANSYS有限元分析软件,对高速透平膨胀制冷机的转子进行建模与分析。得到不考虑轴承的各向异性与交叉刚度阻尼时等计算了转子的临界转速与振型,考虑了施加在透平轮与压气机轮上四种不平衡激励力和轴承各向异性对转子不平衡响应的影响,其中在不同向激励力下,转子锥动出现了共振分离现象。2.介绍了高速气体轴承-柔性转子结构轴系实验台,实验系统总体可以划分为实验本体、供气系统、计算机控制与数据采集系统等,各系统统一与协调,并预留多个接口,以提高系统可靠性。其中的振动信号数据采集分析系统,以频谱分析、三维谱图、伯德图、轴心轨迹图、时间幅值曲线、分岔图和时间转速曲线等多种图谱进行振动与动力学分析。3.以实验为研究手段,对气体轴承支承的高速透平膨胀制冷机转子进行相关稳定性研究实验为手段进行高速转子的升速实验,呈现转子锥动分离共振的临界特性,并呈现了转子半速涡动的低频特征,周期性低频振荡现象以及双低频现象。通过实验的方法验证轴承供气温度、弹性阻尼橡胶圈对于轴承支承的临界转速,低频涡动、振荡等稳定性的影响,并得出随着轴承供气温度的增加,转子的临界振幅逐渐增大,而转子的相位并不会随之变化,转子低频响应在温度较高情况下,可抑制低频振荡。实验表明硅胶实验组转子表现较低的振动幅值,提高转子的回转精度,在试验过程中激发了轴承的气膜的低频特征,由于振动边界较低实际对于转子运行仍然有一定稳定裕度。
[Abstract]:With the development of rotating machinery towards high speed, lightness and flexibility, the bearing-rotor system with gas bearing as the supporting part of rotor has been more and more widely used in high-speed turbine. In this paper, the vibration characteristics and stability of high speed rotor supported by aerostatic bearing lubrication are experimentally studied on the basis of a high speed turbine refrigerator. The main ones are 1: 1. The basic finite element theory of rotor-bearing system is introduced, and the finite element model of shaft segment, wheel disk and bearing element is established for the rotor of high-speed turbine refrigerator. Using ANSYS finite element analysis software, the rotor of high speed turbo expansion refrigerator is modeled and analyzed. The critical speed and mode shape of the rotor are calculated without considering the anisotropy and cross-stiffness damping of the bearing, and the effects of four kinds of unbalanced excitation forces and the anisotropy of the bearing on the rotor unbalance response are considered. Among them, the vibration of rotor cone appears the phenomenon of resonance separation under the different direction excitation force. This paper introduces a high speed gas bearing- flexible rotor structure shafting test bench. The experimental system can be divided into experimental body, gas supply system, computer control and data acquisition system, etc., each system is unified and coordinated, and several interfaces are reserved. To improve the reliability of the system. The vibration signal data acquisition and analysis system is used to analyze vibration and dynamics by spectrum analysis, three-dimensional spectrum, Byrd diagram, axis locus, time-amplitude curve, bifurcation diagram and time-rotational speed curve. By means of experiments, the relative stability of the rotor of high speed turbomachine expansion refrigerator supported by gas bearing is studied. The experiment of raising speed of high speed rotor presents the critical characteristic of rotor conical vibration separation resonance. The low frequency characteristic of rotor half speed vortex, periodic low frequency oscillation and double low frequency phenomenon are also presented. The effects of bearing gas supply temperature, elastic damping rubber ring on the stability of bearing support such as critical speed, low frequency vortex and oscillation are verified by experimental method. It is concluded that the critical amplitude of rotor increases with the increase of bearing gas supply temperature. However, the phase of the rotor does not change, and the low frequency response of the rotor can suppress the low frequency oscillation at higher temperature. The experimental results show that the rotor of silica gel experimental group exhibits lower vibration amplitude and improves the rotary accuracy of the rotor. During the test, the low frequency characteristics of the bearing film are excited. Because of the lower vibration boundary, there is still a certain stability margin for the rotor operation.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB651

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