摘要
为了研究汽轮机轴系扭转振动过程中长叶片弯振与轴扭振之间的耦合影响,参考某汽轮机轴系以及末级叶片的结构和材料数据,分别建立了3种有限元模型:叶-盘模型、简化轴系模型和带一级末级叶栅的叶-轴耦合模型,分析了这3种模型在静止和工作转速下的模态振动特征.结果表明:在叶-轴耦合模型中存在叶片模态、轴振模态和耦合模态3种不同的振动模态,这些模态体现了叶片弯振对轴系扭振的影响;受轴系扭振影响,叶-轴耦合模型中叶片的振动特性与叶-盘模型中相比存在一定的差别,但这种差别并不显著;从叶片安全角度考虑,设计时应同时考虑叶片静频和动频,并以叶片振动特性为基础,着重考虑叶-轴耦合时的振动特性,以避开工频波动可能带来的危害.
To investigate the coupled vibration between long-blade bending and shafting torsion of turbogenerator sets,three finite element models were developed according to the geometry and materials of a certain steam turbine,which were respectively the blade-disc model,reduced shaft model and the coupling cascade-shafting model,of which the vibration characteristics were analyzed under static and service conditions.Results show that three kinds of vibration modes exist in the coupling cascade-shafting model,namely the blade mode,shafting mode and the coupling mode,reflecting the effects of blade bending vibration on the shafting torsion.The vibration characteristics of blades in the coupling cascade-shaft model are slightly different from that in the blade-disc model,due to the effect of shafting torsion.For the purpose of blade safety,the static and dynamic frequency of blades should be considered simultaneously during product design,taking the vibration characteristics as the basis,with focus on the coupled vibration of shafting torsion and long blade bending,so as to avoid the risk of resonance.
出处
《动力工程学报》
CAS
CSCD
北大核心
2014年第6期443-449,494,共8页
Journal of Chinese Society of Power Engineering
基金
国家科技重大专项课题资助项目(2010ZX06004-013-02-03
2012ZX06002-017-01-04)
关键词
汽轮机
长叶片
轴系扭振
叶片弯振
模态
耦合振动
steam turbine
long blade
shafting torsion
blade bending vibration
mode
coupled vibration
