Vibration Characteristics Analysis of Integrally Shrouded Turbine Blade Considering Separation and Reattachment

考虑分离和重新接触的涡轮自带冠叶片振动特性分析

¹ School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi'an 710072, China
² School of Mechanics & Engineering Science, Zhengzhou University, Zhengzhou 450001, China

Received: 20 May 2017

Abstract

The nonlinear forced vibration responses of integrally shrouded turbine blade considering different contact state are investigated in this paper. A lumped mass model of integrally shrouded turbine blade considering separation and reattachment of adjacent shrouds and centrifugal stiffening effects is established and its dynamic equation is deduced. Collision force is approximated by linear and cubic springs together which is more realistic, and friction force is approximated by an exponential-type velocity-dependent model. Numerical results indicate that integrally shrouded turbine blade displays very complex nonlinear phenomena and it can experience periodic 1, periodic 2, periodic 3, periodic 4 and chaotic vibration. Gap asymmetry leads to more complicated motions of the shrouded blade.

摘要

研究了涡轮自带冠叶片在考虑叶冠间不同接触情况下的非线性振动响应。建立了考虑相邻叶冠间的分离和重新接触以及离心刚化效应的涡轮自带冠叶片的弹簧质量模型，并推导了其动力学方程。碰撞力采用更符合实际的线性弹簧和非线性弹簧的组合来进行建模，摩擦力则采用依赖速度的指数型摩擦模型。仿真结果表明，涡轮自带冠叶片可以表现出非常复杂的非线性现象，并且可以出现周期1、周期2、周期3、周期4和混沌运动。间隙不对称会使自带冠叶片的运动更加复杂。