Research On Temperature Measurement Compensation Method Based On Brightness Turbine Blade Material

Engine turbine blade temperature monitoring technology is the most direct and effective way to evaluate blade thermal load distribution and analyze thermal faults.It not only provides an important foundation for blade heat transfer,aerodynamic research and strength design in the development stage of aero-engines,but also a technical bottleneck for high thrust-to-weight ratio development of aero-engines.Because of its high temperature,high pressure,high load,and multi-gas operation,the speed is as high as 10,000 rpm,making measurement difficult.Aiming at the measurement error of background reflection radiation and absorption spectrum of high temperature combustion gas in the process of engine test,the whole scheme design and system construction of blade temperature measurement are carried out by using non-contact radiation temperature measurement method.The main research work is as follows:?1?In this paper,the measurement difficulties in turbine blades are analyzed in detail.At the same time,penetrating studies have been conducted on the research status of the three major foreign engine design companies in recent years,including General Electric,Rolls-Royce and UTC.Based on the above,a three band temperature measurement scheme is proposed to solve the influence of the background radiation caused by the heat reflection during the temperature measurement.Meanwhile,taking the influence of the high temperature gas product floating above the blade on the measurement into consideration,such as H₂O,CO₂ and other carbohydrates absorb a large amount of the radiation intensity of the blade in the optical path.Considering the Planck blackbody radiation principle and the minimum resolution of the hardware device,We analyze the spectral absorption band of each gas and select a specific window band to avoid the high absorption spectrum band to achieve temperature measurement accuracy.?2?Based on the three band temperature measurement scheme,we have analyzed the selection principle of infrared optical field in detail,and designed fixed focus and zoom optical probe,scalable collimator and short distance direct insertion rear end optical machine structure.In addition,high speed data acquisition and processing software system has been programed.As for high sampling data caching issues,the large data TDMS file format and two level caching technology are selected to solve the problem of large data loss spillover.It can achieve synchronous acquisition and processing of multichannel data.Finally,the whole blade infrared temperature measurement system was set up.?3?The internal and random errors of the whole system are evaluated by a variety of calibration methods and least square method and the relationship between voltage and temperature has been researched.A small temperature feedback control system is set up to test the single band and three band temperature measurement system with the measurement accuracy is 1?.Besides,the theoretical analysis and experimental test of the distance and angle error have been carried out,It obtains the influence of these factors on the accuracy of temperature measurement under different measurement conditions.The two-point calibration method was used to linearly correct the V-T curve to improve the accuracy of multi-distance and multi-angle testing.