【作者】 杨懿；

【导师】 盛德仁；

【作者基本信息】 浙江大学 ， 热能工程， 2010， 硕士

【摘要】 汽轮发电机组是电力大系统中的原动机和能源生产的重要环节,随着科学技术的进步,汽轮发电机组的容量和运行参数不断的提高,汽轮机向着多跨度、重载荷的方向发展,汽轮机转子结构变得更加复杂,众多非线性因素成为了危及机组安全运行的隐患,人们也对机组的可靠性、安全性和稳定性提出了更高的要求。近年来,为了提高能源利用率,我国超超临界汽轮机组和大型核电汽轮机组迅速增多,汽流激振问题也越来越被重视。为了确保机组运行安全,国内外对汽封结构的改进也采取了不少措施,但有效的理论研究和指导尚为欠缺。由于大多转子动力学方面的研究对于非线性激励的作用考虑不全面,具有一定的局限性。本文在熟悉汽轮机组结构及分析汽流激振引发的事故原因基础上,构建了一个单盘单跨的简单的汽轮机转子模型,在计及转子的弯曲效应、剪切效应以及偏心等因素的同时,综合考虑非线性汽封力、非线性轴承油膜力的综合作用,应用Hamilton原理,并结合有限元方法,推导了转子-汽封-轴承系统的非线性动力学模型。通过数值分析,求得系统的周期响应,根据系统的分岔图、时间历程图、Poincare映射图、频谱图、相位轨迹图等,分析比较了系统在是否考虑汽封力作用下的非线性动力学特性,研究了转速、汽封结构参数、蒸汽参数对系统响应的影响。本文在建模过程中考虑了多种非线性因素的联合作用,更接近汽轮机组的实际运行状况,具有较好的代表性,为消除汽流激振和提高系统稳定性的研究提供了良好的理论基础。更多还原

【Abstract】 Steam turbine-generating unit is the original motive and the key link of energy production. With the development in science and technology, the capacity of steam turbine-generator unit, as well as the operating parameters is continuously increasing, and toward the direction of high-speed, multi-span and heavy loads. Since the steam turbine rotor structures are getting more complicated, many nonlinear factors have become the hidden danger of the safe operation of generating units. So people have raised higher requirements toward the reliability, security and stability of the units.In recent years, in order to raise the energy efficiency, China’s ultra-supercritical and large-scale nuclear power steam turbine group are increasing rapidly, and the problem of steam excited vibration are being much accounted of. For the purpose of ensuring the safe operation of generating units, home and abroad have also taken various measures to improve the structures of the seal, but effective theoretical researches and guidance are still lacking. Since most of the researches, which are in the field of rotor dynamics, haven’t thoroughly considered the effect of non-linear incentive. There exist some limitations.This paper, on the basis of getting familiar with turbine steam structure and analyzing the cause of the steam excited vibration-induced accident, constructed a simple single-disc single-spam turbine rotor model. While taking into account the effect rotor bending, shear effect and eccentricity, the author has comprehensively considered the effect of nonlinear seal force and bearing oil-film force, at the same time, applied Hamilton principle, combined the finite element method, and derived the nonlinear dynamic model of rotor-seal-bearing system. By numerical analysis, this paper obtained the periodic response. According to the system’s bifurcation diagram, time history diagram, Poincare map, frequency spectrum, phase trajectory maps, the author has investigated the nonlinear dynamic characteristic of rotor-seal-bearing system in some specific rotation speeds, seal structures and steam parameters.When modeling, this paper has taken the combined effects of several nonlinear factors into account, which is closer to the actual operation condition of the steam turbine and with better representativeness. All these have laid a better theoretical basis for the research of the elimination of steam excited vibration and improvement of systematic stability.更多还原