Interpretation Technology Of Crystal Temperature Measurement For Aero-engine Turbine Blades

The accurate measurement of turbine blade surface temperature and its distribution are critical to the design,test and maintenance of aeroengine.The method of crystal temperature measurement has the advantages of small size,high precision,array distribution and no lead,especially suitable for turbine blade tenon,platform and high-speed rotating parts in closed or semi-closed environment,and other special positions.Accurate information on surface temperature distribution of aeroengine hot end parts can be provided.In this paper,the research of the SiC crystal temperature measurement technology was carried out with the background of the interpretation technology requirement of the crystal temperature measurement of the aeroengine turbine blade.The main research contents include:the XRD test method of the crystal lattice constant of the SiC crystal,the data processing method of the crystal temperature measurement,the preparation of interpretation technology and the realization of visual interface.In addition,AlN film temperature measurement technology was also carried out.Firstly,the annealing calibration and XRD text method of SiC crystals after neutron irradiation were carried out.The SiC crystals after the neutron irradiation were subjected to an annealing heat treatment by a high-temperature annealing furnace with500-1400℃for 5 min.The Raman spectroscopy results showed that during the annealing calibration process,the new peaks,trailing phenomena and red shift were disappeared at 1100℃.The residual defect concentration of the crystal lattice decreased gradually as the annealing temperature increased and the crystal lattice was restored to the long-range ordered structure.In order to solve the influence caused by the crystal cutting angle,the HRXRD was used to measure the lattice parameters,and the position of the diffraction peak was found byφscanning to perform 2θscanning,and the ideal measurement result was obtained.Furthermore,The 2θand FWHM values increased and decreased with an approximately linear trend as the annealing temperature increases,respectively.Secondly,the date processing method of the SiC crystal temperature measurement was studied.The XRD diffraction patterns of SiC crystal were analyzed to obtain the lattice parameter 2θand FWHM of samples,which were annealed with 5min,10min and 15min at 500-1400℃.And the database of 2θand FWHM with annealing temperature,time were established,and the calibration curve was drawn by empirical formula.And we used the iterative algorithm to calculate the equivalent time of the normalized time history curve of the actual working SiC crystal,and obtained the equivalent times of different normalized time history curves.Then according to the equivalent time,2θand FWHM comparing with the calibration curve,the highest temperature experienced by the SiC crystal was interpreted.Thirdly,the visualization of crystal test data was realized by MATLAB GUI,the standard database was established and the calibration curves of 2θand FWHM were drawn;MATLAB GUI realized the integration of data processing and temperature interpretation process,two interpretation temperature results were optimized into one temperature output.And the GUI file was converted into an EXE executable file to be run as a separate software.The temperature measurement range is 500-1400℃and the initial calculation error of temperature measurement is only 0.447%.Finally,the research of AlN thin film temperature measurement technology was explored.The weakly oriented AlN thin films were prepared by reactive sputtering method.the weakly oriented AlN thin films were analyzed by SEM and XRD techniques.The SEM results showed that the grain growth of the AlN thin films after annealing in the range of 400-1000℃for 60 min;The XRD test results showed that the FWHM and 2θvalues decreased and increased monotonically with the increase of annealing temperature.The AlN particles underwent a recombination of the B₂ bond by annealing with sufficient energy to migrate to the position where defects or gullies exist,and completed the transition from the metastable structure to the hexagonal wurtzite structure.It proved the application potential of（002）weakly oriented AlN thin films for temperature measurement technology.