The Design And Realize Of Multi-wavelength Radiation Temperature Measurement System

After years of development, gas turbine has become core power devices in many areas,such as aerospace, aviation, maritime and electricity. Gas turbine has played a more and more important role in these areas. But the working environment of gas turbine is very complex and usually gas turbine works under high temperature and pressure. Turbine blade is also under enormous pressure, which is the reason of the turbine blade limited using time, its using life directly affects the service life of gas turbine using period. If any tiny fault of turbine blade can't be discovered, it will bring huge loss in industrial production. The status of turbine blade mainly depends on its working temperature which is an important indicator of the quality evaluation. Its temperature is a key element to define whether the turbine blade works well,and the temperature distribution can show us the status of the turbine blade airway and its Thermal barrier coating. We can't get the accurate blade temperature with normal ways because of its complex working environment,so radiation thermometry becomes the first choice of turbine blade temperature measurement.Our researcher group has made single color radiation thermometry device and two-color radiation thermometry device before starting research on multi-wavelength thermometry and got good effect, and single color radiation thermometry has been used in industrial manufacture, but the two kind measurements of thermocouples can't get the emissivity of the turbine blade and they can just measure the radiation temperature instead of the real temperature. Multi-wavelength measurement is used in this paper, which can get the emissivity of turbine blade theoretically.Firstly, the article in-depth studies the basic principles of radiation thermometry. On this basis, the single-color pyrometry, two-color radiation pyrometry, and multi-wavelength radiation pyrometry are introduced in detail. Through theoretical analysis, it explains why multi-wavelength is adopted in this paper. Then, introduce how multi-wavelength radiation pyrometry come out in this paper, including the colorimetric wavelength selecting, the choice of the of photodiode and design of' preamplifier, design of logarithmic circuit and filtering circuit. Finally, we get the data through blackbody calibration measurement and fitting the output into R-T curve, which can be used to measure the characteristic of the multi-wavelength radiation pyrometry. Different material's emissivity can be measured because of limit test conditions,which is the biggest pity of this object.