高速透平机械稳定性评价与控制原理及方法研究

发布时间：2018-03-13 17:16

本文选题：旋转机械　切入点：转子稳定性　出处：《北京化工大学》2017年博士论文　论文类型：学位论文

【摘要】：乙烯、炼油、天然气、化肥等流程工业的生产装置的机组容量不断扩大,旋转机械将面临着高参数化(高转速、高流量、高压比)。这需要加大透平机械转子轴承跨距,导致转子系统挠性增加,转子-轴承系统的稳定性问题将面临着严峻考验。本论文围绕高速旋转机械的稳定性问题开展了稳定性预测、评价及控制方面的研究,提出了柔性转子系统模态阻尼比、轴承参数的辨识方法,发明了一种新型电磁主动阻尼密封结构以实现对转子稳定性的控制,具体内容如下:1、提出了基于“短时傅里叶滤波+直接频响函数+预测误差法”的转子阻尼比识别方法,解决转子稳定性识别面临的噪声干扰、多阶模态混合、陀螺效应等问题。从数值方法和试验方法两个角度验证了该方法具有抗噪声干扰能力好、测试结果精度高、稳定性好的特点。该方法能充分整合整机频响函数,对模态参数进行统一识别,提高识别结果准确性。采用两类典型的离心式压缩机结构模型模拟扫频激励,研究了考虑密封结构参数和轴承预负荷因素下的识别情况;结果表明,该方法可以解决正反进动模态叠加问题,能广泛适用于高速旋转机械稳定性参数识别。同时,针对扫频识别方法,提出了两种信号预处理方法,均可以提高频响函数特征信号的信噪比,有利于提高稳定性参数识别结果的可靠性。2、揭示了电磁扫频过程中,电磁激振器线圈偏置电流、扰动电流和转子偏心等因素对稳定性参数识别结果的影响规律。偏置电流会给转子系统引入负刚度,引起转子的稳定性参数改变,其对识别结果作用规律与安装位置有关;在相同偏置电流情况下,扰动电流的幅值对识别结果几乎没有影响。指出实际加载过程应选取小的偏置电流,而扰动电流根据不平衡振动幅值来选择。并且在小偏执电流加载情况下,可以忽略电磁轴承的位移反馈力,直接使用扰动电流作为系统输入进行参数识别。围绕如何在实际机器上实现扫频激励的问题,开发了针对实际应用机组的扫频激励的软硬件系统。利用电磁扫频技术研究了不同预负荷、不同转速、不同润滑油供油参数以及不同轴承静态比载荷的轴承-转子系统稳定性变化情况。研究结果表明,预负荷增加、转速增加、比载荷增加会降低被测转子系统的稳定性,润滑油油温(43-48℃)和油压(0.1 MPa-0.175 MPa)增加可以提高转子稳定性。3、提出了基于电磁激励和有限元模型识别柔性转子-轴承系统的轴承参数的方法。(1)在可以充分安装传感器时,采用双截面插值迭代法。该方法基于有限元模型对测量数据进行插值迭代,解决了轴承中心位置和振动传感器测点不一致的问题。该迭代方法收敛快,主刚度和主阻尼的识别结果波动小;试验数据处理结果中,测量振型与预测振型十分匹配。(2)在安装传感器位置受限时,采用闭环系统参数辨识法。将轴承-转子系统转为控制对象与控制器的闭环控制系统后,轴承参数作为控制器参数进行识别,规避了轴承中心位置和振动测点不一致的问题。两种方法采用单点频率激励获得的轴承参数来预测的模态参数和通过扫频识别的模态参数都一致,验证了该方法识别结果的准确度和可信度,为简化扫频测试转子稳定性提供了基础。准确获取轴承参数可以避免昂贵的满负荷、满压力的稳定性测试试验。4、发明了电磁阻尼密封及带这种密封结构的离心式压缩机结构,解决了控制器在离心压缩机内的工程安装问题,标定试验证明了发明的主动电磁阻尼密封结构具有良好的力学性能参数,能够满足振动控制需要。结合电磁轴承的线性化控制力方程,推导了转子稳定性控制原理方程。从基本控制原理出发,研究了针对转子失稳故障的控制方法,提出了反向交叉刚度增稳和主动阻尼增稳两种控制算法。采用数值仿真和试验验证的方法证明了两种算法能够很好地在线解决转子失稳问题,提高转子-轴承系统稳定性。总之,本文的研究成果对指导高速透平机械的设计、合格检验和失稳控制,具有理论和现实的工程意义。稳定性评价方法和稳定性测试技术可服务于工程测试,并为稳定性和轴承参数测试等相关试验研究提供技术支撑;发明的控制结构使得主动电磁控制距离工业应用更进一步,可解决转子失稳问题。
[Abstract]:Ethylene, oil refining, natural gas, fertilizer and other production equipment in process industry unit capacity continues to expand, the rotating machinery will be faced with high parameter (high speed, high flow, high pressure ratio). The need to increase the turbine rotor bearing span, resulting in increased stability of the flexible rotor system, rotor bearing system will be faced with a severe test. This paper carried out the stability prediction around the stability problem of high speed rotating machinery, research evaluation and control, proposed a flexible rotor system modal damping ratio identification method of bearing parameters, invented a new type of electromagnetic active damping sealing structure to control the stability of the rotor, the specific contents are as follows: 1, put forward the specific identification method based on the rotor damping Fourier filter + + direct frequency response function prediction error method, to solve the noise jamming rotor stability recognition, multi order mode Mixed state, gyroscopic effect and other issues. From two aspects of numerical method and test method shows that this method has good anti noise ability, the test results of high accuracy, good stability. This method can fully integrate the frequency response function, unified identification of modal parameters, improve the accuracy of recognition results. By using two types of centrifugal structure compressor model simulation of frequency scanning, considering the identification of seal structure parameters and bearing preload factors; results show that the method can solve the problem of modal superposition and precession, can be widely used in high speed rotating machinery stability parameter identification. At the same time, the sweep frequency identification method, puts forward two kinds of signal the pretreatment method can improve the frequency response function characteristics of the signal to noise ratio, to improve the stability and reliability of.2 parameter identification results, reveals the electromagnetic frequency sweep process Current, electromagnetic exciter coil bias, influence of disturbance current and rotor eccentricity on the stability parameter identification results. The bias current to the rotor system will introduce negative stiffness, stability of rotor parameters change, its effect on the recognition results of rules associated with the installation position; in the same bias current, current amplitude perturbation almost no impact on the recognition results. It is pointed out that the actual loading process should select a small bias current, and current disturbance is selected according to the unbalance vibration amplitude. And in the case of small current biased loading, displacement can be ignored electromagnetic bearing force feedback, the direct use of perturbation current as the system input parameters. Focusing on how to achieve sweep the problem of frequency excitation on real machines, the development of hardware and software of the system according to the actual application of sweep unit incentive. To study the technology of frequency sweep by electromagnetic With the pre load, different speed, different parameters and different lubricating bearing static load ratio of bearing rotor system stability changes. The results show that the pre load increases, the speed increases, the increase of load ratio will reduce the stability of the measured rotor system, the lubricating oil temperature (43-48 DEG C) and pressure (0.1 MPa-0.175 MPa) the increase can improve the stability of the rotor.3, and puts forward the method of bearing parameter identification of electromagnetic excitation and finite element model of flexible rotor bearing system based on the sensor (1) can be installed in full, using double section interpolation iterative method. The method of finite element model based on the measured data of the interpolation iteration, to solve the measuring point is not consistent the problem of bearing center position and vibration sensor. The convergence of the iterative method, the stiffness and damping of the main identification results of small fluctuations; test data, measurement and prediction of vibration mode Type very match. (2) in the installation position of sensor is limited by the closed-loop system parameter identification method. The bearing rotor system for closed-loop control object and controller, bearing parameters as the parameters identification, to avoid the bearing center position and vibration measuring points of the inconsistency of the modal parameters of two. Methods using single point frequency to predict excitation bearing parameters obtained and the modal parameter identification of sweep frequency, accuracy and reliability is verified by the results of the method, to simplify the frequency sweep test rotor stability provides a basis. To obtain accurate parameters of full load bearing can avoid expensive, the stability test of.4 full of pressure, the invention of the electromagnetic damping and sealing with the sealing structure of centrifugal compressor, solves the installation problem in the engineering controller in a centrifugal compressor, calibration test Proved that the active electromagnetic damping sealing structure has good mechanical properties, can meet the needs of controlling vibration. Using the linear control equation of electromagnetic bearing, equation of rotor stability control principle. Starting from the basic principle, research on the control method of the fault steady loss of rotor, proposed reverse cross stiffness augmentation and active damping augmentation of two control algorithms. By using the numerical simulation method and experiment proved that the two algorithm can well solve the problem of instability of Rotor line, improve the stability of rotor bearing system. The research results of this paper for the design of high-speed turbomachinery guidance, inspection and control instability and it has theoretical and practical engineering significance. The stability evaluation method and stability testing technology can serve the engineering test, and related test stability and bearing parameters testing experience The research provides technical support; the invention of the control structure makes the active electromagnetic control further to the industrial application, and can solve the problem of rotor instability.

【学位授予单位】：北京化工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH133.3

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