Research on Fan Acoustic Mode Measurement Method of Turbofan Engine

Spinning mode measurement is an important basis for researching on in-duct acoustics of turbofan engine. The identification decomposition method and test measuring device based on rotating radial microphones array were developed by analyzing the acoustic propagation mechanism and test technology. To verify the method, the acoustic measurement tests were conduct by applying the test platform of the spinning mode synthesizer. The test results indicated that the method can identify the circumferential and radial acoustic modes with a small number of microphones. The results decomposed by three different measuring methods were consistent, showing good applicability of the method.