旋转机械转子及支撑系统振动模态与响应研究

论文总字数：25240字

摘 要

转子系统是旋转机械的核心部件，如航天发动机，燃气轮机，汽轮机，压缩机和泵。其动态特性直接影响设备的安全运行。本文利用有限元分析技术建立了试验台转子 - 轴承系统的三维实体模型。研究了这种试验台支撑系统在不同工况下的模态响应特性。基于实验数据，进行有限元计算和修改。最后，通过计算结果得到试验台的模态响应。研究其特点，为进行机械转子--支撑系统结构改进和设计提供理论依据。

一般情况下，分析转子本身或转子轴承系统，可以用于研究转子系统的动力学特性。但是，许多理论和实验研究已经证实，在固定工况下，应当考虑基础的影响，来更加直观准确地认识旋转机械的动态特性，并对于整个转子支承系统做分析。因为基座本身并非不具有弹性的，并且基座上的支撑部件是以耦合的方式组合的，如果不考虑基座可能发生的谐振和谐波响应，则基座--转子--轴承耦合系统的内部谐振就有可能在工作速度范围以内发生，严重影响转子机械运行安全。上世纪五六十年代，受限于计算机技术发展和理论有限，学者们大多只对转子系统进行分析。如今，计算机计算资源大大提升，转子动力学理论进一步完善，对于转子-支承系统的研究将进一步深入发展。在工程领域的应用中，转子--轴承系统的模态、响应及动力学特性也需要进行深入的研究。过对转子-支承系统模态响应的研究，丰富了转子动力学理论体系，对于工业生产有着深远的指导意义。

本文以某旋转机械振动试验台为对象，建立了转子-轴承-基座系统的有限元三维实体模型，研究了整个转子--轴承--基础系统在弹性基座作用下的临界速度和主振动模态，研究了转子-支承耦合系统在一阶、二阶转速下对于转子系统和支承系统所产生的不同影响，并且对转子系统进行了不平衡响应分析。

关键词：有限元法； 转子-支承系统； 固有频率； 谐响应分析

Abstract

The rotor system is a core component of rotating machinery such as aerospace engines, gas turbines, steam turbines, compressors and pumps. Its dynamic characteristics directly affect the safe operation of the device. In this paper, a three-dimensional solid model of the rotor-bearing system of the test bench is established by using finite element analysis technology. The modal response characteristics of the test bed support system under different working conditions were studied. Based on experimental data, finite element calculations and modifications are performed. Finally, the modal response of the test bench is obtained by calculation. Study its characteristics and provide theoretical basis for structural improvement and design of mechanical rotor-support system.

In general, the analysis of the rotor itself or the rotor bearing system can be used to study the dynamics of the rotor system. However, many theoretical and experimental studies have confirmed that under fixed conditions, the influence of the foundation should be considered to more intuitively and accurately understand the dynamic characteristics of the rotating machine and to analyze the entire rotor support system. Since the susceptor itself is not inelastic and the support members on the pedestal are combined in a coupled manner, the pedestal-rotor-bearing coupling is not considered if the resonance and harmonic response that may occur to the pedestal are not considered. The internal resonance of the system may occur within the working speed range, which seriously affects the safety of the rotor mechanical operation. In the 1950s and 1960s, limited by the development of computer technology and limited theory, scholars mostly only analyzed the rotor system. Nowadays, computer computing resources have been greatly improved, rotor dynamics theory has been further improved, and research on rotor-support systems will be further developed. In the field of engineering applications, the modal, response and dynamics of the rotor-bearing system also require in-depth research. The study of the modal response of the rotor-support system enriches the rotor dynamics theory system and has far-reaching guiding significance for our industrial production.

In this paper, the finite element solid modeling modeling model of the rotor-bearing-base system of the National Vibration Center of Southeast University is established by means of physical modeling. The critical speed and main vibration mode of the whole rotor-bearing-basic system under the action of elastic base are studied, and the difference between the rotor system and the support system in the first-order and second-order rotational speeds of the rotor-support coupling system is obtained. Impact and an unbalanced response analysis of the rotor system.

KEYWORDS: finite element method; rotor-bearing system; natural frequency； Harmonic response analysis

目录

摘要 I

Abstract II

第一章 绪论 1

1.1研究背景及意义 1

1.2旋转-支承系统机械振动模态研究现状 2

1.3本文的主要研究内容 4

第二章 转子-支承系统分析动力学理论基础与有限元方法基本原理 6

2.1转子-支承系统分析动力学理论基础 6

2.2有限元方法介绍 8

2.3小结 14

第三章 实验台、实体仿真模型介绍 15

3.1实验台介绍 15

3.2实体建模内容 15

3.3典型模态实验实例 18

3.4总结 19

第四章 转子-支承系统三维实体有限元分析模型 20

4.1软件简单介绍 20

4.2转子-支承系统动力特性实体有限元分析模型 21

4.3总结 28

第五章 振动模态及其分析 29

5.1模态分析 29

5.2转子系统圆盘位置的影响分析 36

5.3总结 39

第六章 总结与展望 40

6.1总结 40

6.2展望 41

参考文献 42

致谢 44

1. 绪论

1.1研究背景及意义

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