含裂纹叶片的轴流式压气机整体叶盘振动特性分析

Vibration characteristics analysis of blisk with cracking blades on axial flow compressor

某型轴流式压气机性能试验过程中出现转子叶片裂纹故障.结合该型压气机结构特点,分析了振动响应的时域信号、频域信号以及高频成分出现的频率波动现象,总结了含裂纹叶片的轴流式压气机整体叶盘振动特性.分析结果显示:含裂纹叶片的整体叶盘使得轴流压气机振动响应呈现非线性特性;振动频谱中出现共振峰分离现象,表明叶片裂纹引起轴流压气机1级转子叶盘出现结构失谐;随转速升高,两个共振峰对应频率均出现波动现象(波动周期分别约为8s和9.2s),叶片裂纹不断扩展且数量增加,整体叶盘失谐程度不断加深,整体叶盘系统出现低阶模态局部化现象.

Crack fault of rotor blades occurred during performance experiment of an axial flow compressor. According to the structure characteristics of the compressor, the time-do- main signal, frequency-domain signal of vibration response and high-frequency fluctuation were analyzed, and vibration characteristics of blisk with cracking blades on axial flow com- pressor were summarized. The results show that the blisk with cracking blades can cause vi- bration response of the axial flow compressor to present the nonlinear characteristics and the splitting of formant in the vibration frequency range, indicating the blade crack could induce mistuning of the first-stage rotor blisk of the axial flow compressor. With the rise of the speed, the frequencies of two formants fluctuate （periods of fluctuation about 8 s and 9.2 s respectively）, and the blade crack grows and the number of cracking blades increases, so the mis- tuning extent of the blisk increases and modal localization of low order modes of the blisk appeares.