Research on Vibration Modes and Acoustic Radiation Modes for Civil Aero-Engine Blade

Vibration and radiated sound of civil aero-engine are harmful to environment and safeness. Engine blade is its major part bringing vibration. The paper probes into a method adapted to an aero-engine blade, it is the new method of indirect measurement of vibration, which both vibration and radiation behavior is represented using acoustic signal and theory of radiation modes. Based on investigation on the basic coupling relationship between structural vibration and acoustic radiation, the radiation sound-pressure modes theory is presented, and the radiation modes parameters are deduced. The relationship between radiation modes parameters and vibration modal parameters is also discussed. Besides, the vibration and acoustic radiation characteristics of the aero-engine blade under simulated real-working condition are identified through the experiment method. The paper put forward the new method to the active structural acoustic control (ASAC). It can also be applied to obtain the reliable experiment data in lower noise design of the aero-engine components.