Research On Active Thermometry Based On Infrared Dual Wavelength Laser

Accurate measurement of the true surface temperature is of great importance in metrology and aerospace.Radiation thermometry is a common method for surface temperature measurement of high temperature targets.The difficulty of measuring the emissivity of high temperature target accurately and the reflection interference of complex environment are the two major problems for radiation temperature measurement method facing in practical application.Therefore,in this dissertation,under the condition of environmental reflection interference and unknown emissivity,the true surface temperature of high temperature material is precisely measured and studied based on the active thermometry of dual wavelength infrared laser.The specific research contents and main research results are as follows:Firstly,an active thermometry model is developed based on the photothermal effect of dual wavelength infrared laser-material.The influence of instrument constants and wavelength mismatching on active thermometry are analyzed based on the calibration model of instrument constants for active thermometry,and a modified model of active thermometry is established under wavelength mismatching.Secondly,an active thermometry system is designed and built based on the theoretical model of dual wavelength infrared laser active thermometry.From the perspective of wavelength selection and temperature rise radiation detection method,a near infrared laser light source subsystem and a photoelectric detection subsystem are established respectively.Thirdly,the calibration experiment of the active thermometry system is carried out.The central wavelength of the active temperature measuring system is calibrated,and the accuracy of the central wavelength is verified by spectral responsiveness calibration.A calibration device for the instrument constant is designed and set up,and the surface temperature deviation of the calibration sample at 1173 K is better than 0.02%,which proved that the calibration device could achieve stable and uniform heating of the sample.The calibration experiments are repeated in the temperature range of(873?1173)K,and the relative standard deviation of the instrument constant is 0.28%.Finally,the experimental study of active thermometry is carried out.In the temperature range of(873?1223)K,active temperature measurement experiments are carried out on samples with different radiation characteristics,the average deviation from the reference temperature is(0.3%?0.8%).By setting different environmental reflection interference,antiinterference temperature measurement experiments are carried out.The average temperature deviation of the active thermometry system is 8.6K,which is equivalent to the results of the active thermometry under the condition of no environmental reflection interference.At1173 K,the relative standard uncertainty of the high infrared radiation characteristic sample is measured by the active thermometry system that reaches 1.12%(k=2).The results show that the active thermometry technology has excellent ability of temperature measurement without emissivity and resisting ambient reflection interference.The temperature measurement method studied in this dissertation can provide effective technical support for high precision measurement of high temperature material surface temperature in aviation and other fields.