Research Of Infrared Temperature Measurement Method For Titanium Alloy During Ignition

Titanium alloys is the indispensable material for the aero-engine to decrease the weight of structure and improve thrust-to-weight ratio,because of the excellent performance,such as specific stiffness,specific strength and corrosion resistance.It has been widely used in the turbine blade,leading blade,turning vane and other core part of advanced aero-plane engine.However,during the parts made of Titanium alloy works in the circumstance of high temperature and friction,it can catch fire easily,which will lead to the engine burn down and will limit the application filed.Temperature is an important symbol during the titanium fire happens,which plays an important role in the aero-plane engine preliminary development,mid-term test,post manufacture and maintenance.The infrared temperature measurement method is widely used in the area concerning owing to the high accuracy.Aiming to meeting the demand for preventing the titanium fire,this paper describe a way to stimulate the titanium fire accident by using oxy-acetylene flame to ignite the titanium alloy and measure the temperature during the ignition of titanium alloy accurately and in time.The main research content is below:(a)By analyzing the advantage and disadvantage of traditional temperature measurement method and the widely used infrared temperature measurement method,the latter method is chosen as the temperature measurement method during the ignition of Titanium alloy.The temperature measurement wavelength is selected according to the infrared temperature measurement basic law,the sensitivity to temperature of wavelength and gas infrared absorption thesis.(b)Set up the temperature measurement system according to the radiation intensity and emissivity measurement method.The system includes the design of light system,precision mechanical structure and the high speed data acquisition circuit system,which guarantee the correct reception,conversion and communication with personnel computer.The software designed by using the software Labview based on graphical programming is good for the data displaying and analyzing.(c)Taken into the actual application condition of infrared temperature measurement system,the possible interferences are analyzed and relative algorithm to overcome the influence is provided.Describe the method of radiation intensity and emissivity based on the designed temperature measurement system.At the same time,offer the algorithm for the feature extraction to get the information about the ignition temperature.(d)Choose the TC4(Ti-6Al-4V)as the experimental material and calibrate the 940 nm channel and 1050 nm channel before the experiment.By analyzing the experimental result,the temperature range of measurement system is 500~2000 oC,the uncertainty is 1oC during the high temperature oxidize(500~900oC),and the range temperature during the ignition process is 1653.4~1857.1oC.And the ignition temperature is 1615.5 oC with a uncertainty of 1%.At last,the temperature measurement principle is extended to the thermal imaging temperature measurement during cutting KH2PO4(KDP)used to manufacture the parts of high power laser system,which can provide data support and guidance function for the precision finishing of KDP.