【作者】 胡宇达；

【导师】 邱家俊；

【作者基本信息】 天津大学 ， 一般力学与力学基础， 2003， 博士

【摘要】 大型汽轮发电机定子端部绕组及其结构的安全性与可靠性直接影响着整 个机组和电网的工作状况而电磁力激发下绕组结构的振动是导致端部事故的 主要原因因此 对定子端部绕组的振动问题进行研究以便为工程实际提供 更加合理的设计方案具有非常重要的意义本文正是以此为出发点针对二 十万千瓦大型汽轮发电机的工程背景开展了研究工作所得结论可为实际问题 的解决提供理论依据研究内容概括为以下五部分 1 将端部绕组电流密度进行富氏展开后运用分离变量法对麦克斯韦电磁 场方程进行了求解得到了定子端部绕组区域的磁感应强度和绕组所受电磁力 的表达式从而为进一步研究电磁力激发下绕组的振动问题奠定了基础通过 给出的数值计算结果展示了电磁量的变化规律及最大电磁力发生的位置 2 首次应用电磁固体动力学理论考虑变形场和电磁场的影响因素建立 了研究定子端部绕组复杂振动现象的分析模型得到了电磁力与摩擦力共同作 用下绕组的非线性磁固体振动方程以及电磁力作用下绕组的双向磁固耦合振 动方程 3 运用多尺度法对绕组的单自由度和两自由度主共振问题进行了求解得 到了幅频响应方程并对定常解的稳定性和分岔奇异性等问题进行了分析通 过给出的数值计算结果得到了描述系统复杂动力学现象的新规律并分析了 电流值摩擦参数等对解的多值性跳跃现象以及系统的周期运动锁相等非 线性动力学行为的影响阐述了共振发生时的危害性另外 通过对绕组双向磁固耦合振动问题进行分析求解给出了组合共振发生时的稳定性条件研究 方法可为多因素作用下构件的复杂动力学问题分析提供借鉴 4 首次在复合材料理论的基础上通过叠层复合材料加筋圆锥壳模型的建 立 对电磁力激发下定子端部绕组整体的电磁固体振动问题进行了研究得到 了绕组整体所受电磁力及有关弹性常数的表达式从而为发电机复杂振动问题 的研究提供了理想的分析模型利用伽辽金积分法及振型的正交性分别得到 了固有振动问题的广义特征值方程和电磁力激发下的动力响应控制方程并通 过数值算例指出了支架数目及电流值对振动特性的影响 5 在弹性曲梁理论的基础上首次建立了定子端区汇水管的磁固耦合振动 方程 推得了方程中电磁力的计算式通过采用解析法和有限元方法进行计算 指出了不同约束条件对汇水管固有振动特性的影响此外 采用有限元方法对不同工况下鼻端空心引水线的固有振动问题进行了计算分析提出了避免共振 现象发生的条件 4 <WP=5>更多还原

【Abstract】 Stability and reliability of stator end winding and its structure in a large turbo-generator can affect operating conditions. Winding vibration excited by electromagnetic force may lead to accidents.So it is important to study the vibration problems so as to provide more reasonable designing basis for projects.This thesis makes researches on a 200MW large turbo-generator.The results obtained can provide theoretical basis for solving practical problems. The mainwork can be outlined as follow: 1. Based on Fourier expansion of current density, with separation of variablesmethod, we getexpressions of magnetic introduction intensity and formulas ofelectromagnetic force. Through numerical simulation, wecan find the lawof electromagnetic parameters varying andgive the locationwhere maximumelectromagnetic force occurs. 2. Through a model, which is used to study complex oscillation of the end winding, we obtain nonlinear magnetoelastic vibration equations with electromagnetic forceand friction force interaction. Meanwhile, we get double-direction vibration equations under electromagnetic force. 3. Fundamental resonance of one degree of freedom as well as two degrees offreedom is studied by multiple scales method. Through response equations,we analyzestability and bifurcation of the steady-state solution. The numerical resultsshow new phenomena of the system and point out the effect of current and friction coefficients on the system nonlinear behaviors. Besides, stabilitycriteria of combination resonance are established by analyzingthe double-direction vibrationequations. 4. Through a model of stiffened laminated composite conical shell, electromagnetic 6 <WP=7> 第一章绪论vibration of whole end winding is studied.Expressions of electromagnetic forceand related elastic constants are derived. Generalized equations of inherent vibration as well as control equations are obtained by Galerkin integration and orthogonality of each mode.Through numerical calculation, we discuss the effect of support numbers and current value on vibration characteristics. 5. Based on elastic bent beam theory, magnetoelastic vibration equations of end collector ringof the statorare set up. Electromagnetic force in the equations isderived. Using analytic method and finite element method respectively, we discussinherent property of the collector ring in different restrictive conditions.Also,inherent property of diversion water pipe in different conditions is analyzed by finite element method. Also, conditions that avoid resonance are represented.更多还原