摘要
基于有限元方法建立了叶轮的动力方程和N阶自由度系统的自由振动微分方程,并对方程中非线性初应力刚度矩阵进行了线性简化;应用Ansys有限元软件对透平膨胀机工作状态下的闭式叶轮和半开式叶轮分别进行了带有预应力结构的模态分析,得到了其在惯性力作用下的振动特性和振动形式;同时对不同转速下闭式叶轮的模态进行了计算分析.结果表明:叶轮离心力的刚化作用对振动频率的影响较为显著;由于离心力的刚化作用,叶轮的固有频率比静频时有所提高;随着转速的提高,叶轮的振动频率也随之加快.
The dynamic equation and the free vibration differential equation of n-degree freedom system were established for the impeller based on the finite element method,and the nonlinear initial stress stiffness matrix in the equations was simplified with linearity.The modal analyses for the closed and semi-open impellers of turbo-expander with pre-stressed structure under working conditions were made respectively based on the finite element software of Ansys.The vibration characteristic and vibration form under inertia force action were obtained,and calculation analyses for closed impeller mode with different rotating speed were made as well.Results show that the rigidization effect of impeller centrifugal force has significant impact on vibration frequency.Because of this effect,the natural frequency of impeller is higher than static frequency,and the impeller vibration frequency will also rise with the increase of rotating speed.
出处
《动力工程学报》
CAS
CSCD
北大核心
2010年第3期161-165,共5页
Journal of Chinese Society of Power Engineering
基金
兰州理工大学博士基金资助项目(BS05200906)
关键词
透平膨胀机
叶轮
振动特性
振动频率
模态分析
有限元分析
turbo-expander
impeller
vibration characteristic
vibration frequency
modal analyse
finite element analysis
