Effect of Support Stiffness Anisotropy on Whirl State of Dual-rotor Systems
To improve thrust-to-weight ratio of aircraft engine,engineering solution measures for stator system often leads to the support stiffness anisotropy of the rotor system,and then have a significant impact on dynamic characteristics of the rotor system.In this work,a calculation model of dynamic characteristics of the dual-rotor system with anisotropic support stiffness is established.Based on verification of the accuracy of the calculation model,the effects of the isotropic and anisotropic support stiffness on natural frequency,whirl state and unbalance response of the dual-rotor system are studied.The results show that when the support stiffness is isotropic,the low order natural frequency lines in the Campbell diagram of the dual-rotor system cross.However,the anisotropy of the support stiffness makes the lower order natural frequency lines tend to separate from each other.For isotropic support stiffness,the unbalance force only excites forward whirl of the rotor system,and the whirl orbit of the rotor system is circular;while for anisotropic support,the unbalance force excites both forward and backward whirls of the rotor system,and the whirl orbit of the rotor system is ellipse.When the support stiffness is anisotropic,whirl direction may be different at different positions of the rotor system at some spin speeds.Support damping can reduce unbalance response amplitude of forward and backward whirls and the spin speed range of the backward whirl,and the adverse effects of support stiffness anisotropy on the dynamic characteristics of the rotor system are also weakened.
vibration and wavedual-rotor systemanisotropic support stiffnessdynamic characteristicsunbalance responsebackward whirl
万方数据
维普
