本文選題：水輪發(fā)電機組　切入點：振動　出處：《大連理工大學》2014年博士論文　論文類型：學位論文

【摘要】：隨著社會與經(jīng)濟的迅猛發(fā)展,水輪發(fā)電機組正朝著大型化、高速化和大功率方向發(fā)展,集成化程度越來越高。隨著水電在電力能源結(jié)構(gòu)中比例不斷增加,其對電網(wǎng)穩(wěn)定運行所帶來的影響也逐漸加大。在水力、機械和電磁等外界因素的相互影響下,機組振動問題日益突出,由此引發(fā)的非線性動力學現(xiàn)象廣受工程界和學術(shù)界關(guān)注,已成為水電行業(yè)的熱點研究之一。本文以水輪發(fā)電機組軸系為研究對象,考慮到振動問題在機組運行過程中的普遍性,對轉(zhuǎn)子-軸承系統(tǒng)在不平衡磁拉力作用下的動力特性、電磁力與密封力聯(lián)合作用下系統(tǒng)的非線性動力學行為、水輪機轉(zhuǎn)輪-密封系統(tǒng)的穩(wěn)定性和由不平衡磁拉力(Unbalanced Magnetic Pull, UMP)引起的機組定、轉(zhuǎn)子碰摩動力學特性等進行了系統(tǒng)的分析,論文主要研究內(nèi)容和成果如下： (1)針對以往多從單一方面分析UMP或密封力激勵下機組運動特性的問題,建立了考慮UMP和非線性密封力共同作用的機組轉(zhuǎn)子-轉(zhuǎn)輪-密封系統(tǒng)模型。該力學模型較好地反映了系統(tǒng)的非線性動力學行為,通過參數(shù)的敏感性分析可以進一步揭示其非線性失穩(wěn)的產(chǎn)生和發(fā)展變化規(guī)律,為機組動力設(shè)計和運行穩(wěn)定控制提供理論支撐。 (2)建立了機組轉(zhuǎn)子-軸承系統(tǒng)的非線性電磁動力學模型和運動微分方程,從轉(zhuǎn)子軸心軌跡和頻域兩方面,重點分析了軸承參數(shù),如軸承長徑比和軸頸間隙在有無UMP情況下對系統(tǒng)橫向振動特性的影響,為機組振動故障診斷以及在UMP作用下的動力特性分析提供了參考。 (3)針對定、轉(zhuǎn)子在UMP作用下的碰摩問題,首次建立了UMP作用下水輪發(fā)電機組碰摩轉(zhuǎn)子-軸承系統(tǒng)的非線性動力學模型,并以與UMP大小關(guān)系最為緊密的參數(shù)之一一勵磁電流作為重點分析對象,研究了其變化對系統(tǒng)動態(tài)特性的影響。該模型可以較好地反映碰摩轉(zhuǎn)子系統(tǒng)在勵磁電流變化過程中所呈現(xiàn)的一系列非線性動力學行為,能夠解釋系統(tǒng)在UMP與碰摩力耦合作用下的振動現(xiàn)象及其發(fā)生發(fā)展規(guī)律,為提高機組振動故障診斷的準確性與振動主動控制提供了有益借鑒。 (4)在對轉(zhuǎn)子-轉(zhuǎn)輪-密封系統(tǒng)動力特性分析的基礎(chǔ)上,研究了水輪機轉(zhuǎn)輪-密封系統(tǒng)在線性、非線性密封力作用下的穩(wěn)定性及失穩(wěn)臨界轉(zhuǎn)速。根據(jù)不同密封參數(shù)對失穩(wěn)臨界轉(zhuǎn)速的影響規(guī)律,給出了系統(tǒng)減小、甚至避免自激振動的路線或措施,為機組轉(zhuǎn)輪-密封系統(tǒng)的動態(tài)設(shè)計和穩(wěn)定運行提供了參考。
[Abstract]:With the rapid development of society and economy, hydro generating unit is facing the large scale, high speed and high power direction, the integrated degree is higher and higher. With the hydropower in power energy structure in the proportion is increasing, its influence on the stable operation of the power grid is gradually increasing. In the interaction of mechanical and hydraulic. Electromagnetic and other external factors, unit vibration problems have become increasingly prominent, nonlinear dynamical phenomena caused by the wide attention of engineering and academic circles, has become a hotspot in the hydropower industry. Based on the shafting of hydraulic turbine generator unit as the research object, considering the universality of the vibration in the operation of the unit in the process of rotor bearing the system under unbalanced dynamic characteristics caused by magnetic force, the electromagnetic force and the sealing force combined effect of nonlinear dynamic behavior of the system, the turbine runner sealing system stability and not by The dynamic characteristics of stator and rotor rubbing caused by balancing Unbalanced Magnetic Pull (UMP) are systematically analyzed. The main contents and achievements of the paper are as follows:
(1) according to the previous analysis from a single UMP or motion unit sealing under the excitation problem, a system model is established considering the rotor - and UMP nonlinear seal force interaction of the runner - seal. The mechanical model can reflect the nonlinear dynamical system, through the sensitivity analysis of parameters can be further revealed the nonlinear loss produced steady variation and development, for the design and operation of power stability control to provide theoretical support.
(2) to establish the nonlinear electromagnetic dynamics model and differential equation of motion of rotor - bearing system, from the two aspects of the rotor axis locus and frequency domain, focuses on the analysis of the bearing parameters, such as length to diameter ratio of bearing and shaft in the gap has no effect on the transverse vibration characteristics of the system UMP, which provides a reference for the vibration fault the diagnostic unit as well as in the UMP under the action of dynamic analysis.
(3) for a given rotor under the action of UMP, rubbing, first established a nonlinear dynamic model of UMP under the action of turbogenerator rubbing rotor bearing system, and the parameters of one of the most closely to the excitation current and UMP size relations as the key analysis object, to study the effects of the change of dynamic the characteristics of the system. The model can reflect the rotor system appears in the excitation current changes in the process of a series of nonlinear dynamical behavior, can explain the system in the UMP and rubbing force under vibration and its occurrence and development regularity, provide a useful reference for active control to improve the accuracy and vibration fault diagnosis the unit.
(4) based on the analysis of the dynamic characteristics of the rotor system - wheel - seal, the turbine runner sealing system in linear, nonlinear stability of seal under the action of stress and critical instability speed. According to the influence of different parameters on seal instability critical speed, gives the system reduced, or even avoid self-excited vibration the route or measures, provide a reference for the dynamic design and stable operation of the unit runner seal system.

【學位授予單位】：大連理工大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM312

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本文編號：1635921