基 于 声 模 态 分 解 的 风 扇 叶 盘 同 步 振 动 辨 识

It is important to apply the non-contact and non-invasive approach to the vibration measurement of aero-engine blisks in aero-engine development，experiments and safety operation. An acoustic mode decomposition based approach is proposed to realize the identification of synchronous vibration of the blisk. The run-up and run-down experiment of a three-stage fan test rig is conducted，where the ring microphone array is placed at the inlet duct and several strain gauges are glued on the rotor blade. The Blade Passing Frequency（BPF）of the acoustic pressure signal is analyzed with respect to the rotational speed. With the mode decomposition at BPF and the Campbell diagram，the mapping relationship between the dominant mode order and the nodal diameter number of the blisk is established. The results of acoustic and vibration tests show that the resonance of the blade occurs when the number of the dominant mode order equals to the nodal diameter number of the blisk，where the proposed approach can effectively identify the synchronous vibration parameters of the blisk；the rotor blades have interacted with both the forward and backward rows of stator vanes，where the generated acoustic modes hold broadband characteristics and the mode scattering phenomenon occurs，leading to the multi-modal vibration of the rotor blade；the acoustic pressure can sensitively mirror different modes of blade vibration，and hence can be employed for the non-contact and non-invasive measurement of the aero-engine vibration.