【作者】 汪燕；

【导师】 李录平；

【作者基本信息】 长沙理工大学 ， 动力机械及工程， 2008， 硕士

【摘要】 本文采用理论和和实验相结合的方法,研究透平自带冠叶片冠间碰撞减振的机理及影响减振效果的因素。理论研究方面,本文利用非线性阻尼模型,建立了碰撞阻尼叶片的三维实体单元的整体动力学方程;利用三维建模软件Solidworks建立了等截面直叶片的三维实体造型,并利用有限元软件ALGOR分析了单个自由叶片的动静力特性,并绘制了共振转速图;用仿真方法分析了自带冠三叶片组在不同叶冠间隙、不同激振力幅值和不同激振力频率条件下的振动特性,以及间隙结构的对称性对振动特性的影响。研究结果表明:碰撞结构是一种非常理想的减振结构,具有碰撞条件的叶片可以抑制外力做功;叶冠间隙越小,外力做功能力也越小,也就是说间隙越小,碰撞减振效果越好;叶片动应力对激振力不敏感,在间隙一定的情况下,应力峰值随激振力的大小变化改变不大。在总间隙相等的情况下,不对称间隙的减振效果要优于对称间隙。在实验研究方面,利用叶片动态特性实验台及其测试系统,对等截面带冠叶片的动态特性和碰撞减振机理进行了实验研究。实验结果显示:冠间间隙越小,碰撞减振效果越好;在间隙一定的情况下,应力峰值随激振力的大小变化改变不大,也就是说动应力对激振力不敏感;不对称结构的减振效果要优于对称结构。对比分析表明,实验研究结果和理论研究得到的结果一致。基于上述研究和其他研究者的一些研究成果,对自带冠叶片的碰撞减振的可靠性设计准则做了初探。本文研究成果为透平自带冠叶片的设计和安全可靠性分析提供了有效的方法,对自带围带叶片的研制和改型设计有着重要的工程应用价值。更多还原

【Abstract】 By using theoretical and experimental methods, the mechanism of vibro-impact and the effective factors of Steam Turbine Blades with Integral Shroud are studied.On the theoretical study, a nonlinear damping model has been used to establish integral dynamics equation for three-dimensional entity unit of the collision damping blade. With the help of 3D software Solidworks, the solid models of blade is built. With the aid of FEA software ALGOR, the dynamics and static characteristic of single blade are obtained, and also the Campbell map is drew. Influence of such dimensions as blade shroud clearance, exciting force amplitude and symmetry of shroud clearance structural, etc. The results of the analysis indicate that the collision structural is a good vibration reducing structural, the blade with collision conditions can suppress external force by doing-work. Smaller the gap, better the damping effects. The dynamic stress is not sensitive to the exciting force, which means that the peak stress changes little at a certain gap. Asymmetry gap has better damping effect than symmetry one.On the experimental study, the experiments on dynamics characteristics and blade vibration abatement mechanism of constant section ISB are researched by utilizing the rotor experiment table and a test system. The results of the experiments indicate that smaller the gap, better the damping effects. The dynamic stress is not sensitive to the exciting force; Asymmetry gap has better damping effect than symmetry one; All those results conform to the theoretical analysis results.Basing on the study results above mentioned and research results of other investigators, a preliminary quest of reliability design criteria of ISB is made.The research results provides a effective method to the design and reliability analysis of ISB. And has a important engineering application value to manufacture and model change of ISB.更多还原