Non-synchronous blade vibration analysis of a transonic fan  

作　　者：Yun ZHENG Qingzhe GAO Hui YANG 

机构地区：[1]School of Energy and Power Engineering,Beihang University,Beijing 100191,China [2]Jiangxi Research Institute,Beihang University,Nanchang 330096,China

出　　处：《Chinese Journal of Aeronautics》2023年第1期178-190,共13页中国航空学报（英文版）

基　　金：co-supported by the National Science and Technology Major Project,China(No.2017-Ⅱ-0009-0023).

摘　　要：This study numerically investigates the aeromechanic behavior of a transonic fan model with a flat tip-leading-edge on the NASA rotor 67 test case.Single-passage unsteady calculations at a near stall operating point of 82%design speed show that the dominant frequencies of mass flow were not the harmonics of the rotor rotational frequency.A full-annulus fluid–structure interaction analysis was subsequently carried out to examine the unsteady flows and their interactions with blade vibrations.The results show that the modal displacement of the backward traveling seventh nodal diameter of the second torsion mode grew exponentially,which reveals that the blade vibration was non-synchronous.The vibration pattern indicates that the aerodynamic mode was resonant with the structural vibration mode.Around the rotor tip,the circumferential vortical propagation induced by interactions among the main flow,tip leakage flow,and tip clearance vortex was the source of aerodynamic excitation.To clarify the mechanism of the non-synchronous vibration,the coupling between aerodynamic disturbance and structural response,i.e.,aliasing,was summarized.The frequency spectra of the fluctuating pressure show that an aerodynamic Back-ward Traveling Wave(BTW)was co-aliased to a structural BTW due to the propagation of the cir-cumferential vortex.The correlation between the frequency and free convective speed of the aerodynamic disturbance determined the directions of aliasing.

关 键 词：Aerodynamic disturbance ALIASING Blade vibration Circumferential vortical propagation Traveling wave 

分 类 号：V211[航空宇航科学与技术—航空宇航推进理论与工程]