压气机内部噪声特征与转子叶片声固耦合机理分析

The rotor blade fault of aero-engine compressor is mostly caused by mechanical and aerodynamic excitations. The excitation factors of high intensity sound waves to rotor blades should not be ignored. Based on the noise testing in a turbofan engine compressor, the vibration mechanism of compressor rotor blades and its corresponding relation with noise signal have been investigated. The mechanism of rotating instability unsteady pressure wave in the compressor is expounded. A noise measurement method which based on rigid wall acoustic waveguide is proposed. The internal noise signal testing of the turbofan engine compressor is completed. And the noise signal spectrum and acoustic propagation characteristics are analyzed. The results show that, the internal noise signal spectrum of the turbofan engine compressor presents a peak pure tone component of 1 402 Hz. And this tone component has a specific combination of frequencies with rotor blades. The propagation direction of this tone component noise source is from the back to the front in the airflow direction in the compressor. The noise source frequency is transformed in different coordinate systems based on the rotating instability theory. When the circumferential mode number of the noise source is thirteen, this tone component can modulate the excitation frequency corresponding to the first order vibration frequency of the first stage rotor blades of the high compressor.