摘要
采用三维8节点非协调单元有限元模型,对50MW汽轮机调节级双胞胎叶片的振动特性进行了计算分析.计算结果表明,在工作状态下,温度的影响和离心力的作用使得轮缘周向尺寸增大,造成了叶根的松动,从而导致振动延伸到叶根部分,振动下传不仅导致旋转状态下的固有频率小于相应的静频值,而且由于参加振动叶片的结构刚度和质量的重新组合,导致叶片模态阶序发生了转移.在静止时,叶片的第1阶固有振动为切向振动,第2阶固有振动为轴向振动;在旋转态下,第1阶固有振动变成了轴向振动,第2阶固有振动变成了切向振动.
Vibratory characteristics of twinborn blades of the governing stage for one 50 MW steam turbine were studied using the finite element method. In the finite element model the three dimensional incompatible element with 8 nodes was employed. When the steam turbine is in operation, high temperature and the centrifugal force cause the increase of the rim diameter of disk, give rise to the matching surfaces of roots of adjoining blades loosing, and dovetail parts over radial supporting surfaces taking part in blade vibration. The calculated results show that not only the natural frequency of blades in operating is smaller than the counterparts in stationary but also the modal order of the blade shifts when the blade runs from the stationary to the operating states. In stationary, the first mode is the tangential vibration of blade, and the second mode is the axial vibration. In operating, however, the first mode turns from the tangential vibration mode into the axial vibration mode, and the second mode translates from the axial vibration mode into the tangential vibration mode.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2005年第7期670-672,680,共4页
Journal of Xi'an Jiaotong University
关键词
汽轮机
调节级
双胞胎叶片
振动
有限元法
Accident prevention
Finite element method
Natural frequencies
Three dimensional
Vibrations (mechanical)
