基于谐波平衡法的尾流激励的叶片振动降阶模型方法

Abstract

In aero-engines, downstream blades are forced to vibrate by the upstream wake, which often severely affects the flutter and fatigue performance of blades. Hence, an efficient method is needed for the analysis of this complex fluid-structure interaction phenomenon. A reduced-order model (ROM) method for blade vibration was proposed based on the harmonic balance method. The upstream wake was firstly decomposed into a number of harmonic waves by FFT (fast Fourier transform), and the aerodynamic forces on the blade were obtained through calculation of the amplitudes of aerodynamic forces on the blade due to each harmonic wave; then the blade vibration was fast analyzed by means of the structure dynamic equations for the blade coupled with the aerodynamic ROM. The results show that this method can analyze the flutter characteristics of the blade under wake excitation quickly and accurately.