Study On ECT Sensor Optimization And Algorithm For Online Monitoring Of Lubricating Oil

Modern aircraft engine has complex structure and works in harsh conditions such as large load,high temperature and high speed.If it works continuously to pass over fatigue limit of its material,metal abrasive exfoliates from aircraft engine into the circulation of lubricating oil,and friction damage is gradually intensified to result in failure of equipment.The characteristics of a large number of wear particles in the oil system,such as composition,size,shape and quantity,can be intuitive to reflect the condition of aircraft engine.This paper uses the electrical capacitance tomography(ECT)technology to monitor online the lubricating oil of the engine in order to get the flow and particle condition of the flow in the pipe,which can provide the reference for the engine maintenance.ECT has been widely used in multi-phase flow detection as the advantages of it including high safety factor,non-invasive,good real time and low cost.However,the resolution of reconstruction image is low and imaging speed of it is slow.In this paper,several modules of electrical capacitance tomography are optimized to solve above problems,and ECT system can better monitor online the situation of the lubricating oil pipeline.The main contents of this paper are as follows:1.The characteristics of lubricating oil abrasive in the aeroengine and the advantages of ECT in oil detection are analyzed.And the the technology and development status of oil testing used in the world are introduced and the characteristics and existing research results of ECT are described.2.After analyzing the characteristics of original ECT sensor and research results in the world,a novel electrical capacitance tomography model is proposed that it is based on 16 rotating electrodes.16 electrodes of electrical capacitance tomography in the model is rotated to get multi-group effective data collected by the data acquisition module.3.Principal component analysis(PCA)is used to fuse multi-group data from the rotating electrode of ECT model to get the result that is reconstructed by the reconstruction algorithm to gain reconstructed images.Finally,image correlation coefficient(CORR)and the image error(IME)are used to evaluate objectively the quality of reconstructed images.4.The image reconstructions are generated by using the image reconstruction algorithm to reconstruct the multiple sets of data from the ECT model of the rotating electrode,and thenuse the wavelet transform to reconstruct the reconstructed images to gain final image.And image correlation coefficient(CORR)and the root mean square error(RMSE)are used to evaluate objectively the quality of reconstructed images.5.A variety of reconstruction algorithms are studied by Matlab 2014 a and COMSOL Multiphysics 5.0.And an image reconstruction algorithm based on modified firefly algorithm and Otsu is proposed to improve the quality of reconstructed images.Finally,image correlation coefficient(CORR)and the root mean square error(RMSE)are used to evaluate objectively the quality of reconstructed images.