An Efficient Approach For Identification Of The Status Of Engine Based On Acoustic Emission Technique

Engine,as the "heart" of the aircraft,is a key component to ensure the operational safety in aviation,which reflects the level of manufacturing and industrialization of a country.Engines are exposed to the harsh environment of high temperature,high pressure and heavy loads during its service.Its safety and stability will affect the performance and safety of the aircraft.For this reason,it is necessary to make real-time assessment of the engine's health status and take response measures based on the results of the assessment.For the limitations of traditional health monitoring methods,in this paper,a real engine is used to carry out two types of experiments based on acoustic emission(AE)monitoring technique.Regarding inlet instability and the start-up process of engine,and vibration monitoring techniques were also used for comparative analysis in the same time.In the study of inlet instability of engine,the results showed that the parameters of AE signal such as amplitude,signal strength,root mean square and average signal level can identify the status of inlet instability efficiently,with the continuous deterioration of the inlet instability,theAE monitoring technique start to response when the distortion range reach to 10%,however,the vibration technique only start to response when the distortion range reach to 10%,It proved that AE monitoring technique is feasible to identify the failure of inlet instability,representing a new approach for health monitoring of engine.In addition,an intelligent processing method based on wavelet packet decomposition and BP neural network is performed on analysis the fault signals,its accuracy for fault identification is as high as 97.5%and can be used to classify inlet instability of engine,which provides new ideas for establishing the handling cloud platform for engine's faults.In the monitoring study of the start-up phase of engine,it is found that as the engine speed increases,the AE parameters increase,the main frequency components of the AE signal are gradually simplified,and the signal energy is continuously transferred from the low frequency to the high frequency.