| The aero engine is the heart of the aircraft which works in an extremely environment.And its internal mechanism is under great stress.Especially bearing parts work in high speed,high temperature,high load conditions.The wear is inevitable,and will unknowingly cause sudden failure,serious or even cause plane crash tragedy.The real-time detection of aero engine’s wear condition is very important to the flight safety of aircraft,and its wear will inevitably produce particles.Wear particles produced with lubricating oil flow in the oil pipeline.According to the detection of wear particles’ size,shape,material and other information can effectively evaluate the wear condition of the aero engine and warn the sudden fault timely.It is of great significance to ensure aviation safety.This paper summarizes the research status of on-line detection technology of lubricating oil particles,compares and analyzes the technical characteristics of common lubricating oil particle detection technology,and specifies the technical requirements for on-line detection of lubricating oil particles.The idea of on-line detection of lubricating oil particles using electrical capacitance tomography(ECT)is proposed in this paper.This paper abstract a pair of plates as a capacitance sensor from the ECT sensor and describe the lubricating oil particle’s signal.According to the analysis of the sensor’s structure characteristics,parameters and detection methods,the paper specifies the features of lubricating oil particle’s signal.Through simulation and experiments,the relationship between the lubricating oil particle’s signal and the size,position of the particle is proved.The variational mode decomposition of lubricating oil particle’s signal is proposed.Using VMD extracts the DC component of lubricating oil particle’s signal.And the probability density distribution of this DC component is calculated.Use the mean value of that distribution of lubricating oil particle’s signal’s DC component to estimate capacitance value.It is demonstrated by simulation and experimental results that this method can effectively avoid the interference of noise and raise the signal-to-noise ratio,improve the lubricating oil particles detection performance of electrical capacitance tomography system.The signals of multi plates when single particle and two particles existing in the sensor are processed by this method.And two groups of data are obtained.Use the linear back projection algorithm for image reconstruction.According to the image results,it can obviously identify the existance of wear particles and the quantity of particles.It is proved that electrical capacitance tomography can effectively solve the on-line detection problem of lubricating oil particles. |
