Study Of Spectral Emissivity On-line Measurement Technology

Emissivity is one of the basic parameters which describe material thermal radiation characteristic. It plays an important role in aviation and aerospace, military and national defense, manufacture of industry and agriculture. The fields of satellite heat control, guiding and hiding, solar energy utilization, infrared heating and thermal radiation thermometry are related to material emissivity. Many scholars from home and abroad have been researching material emissivity and have made a good progress in recent years. Spectral emissivty measurement apparatus based on FT-IR have been constructed in Europe, America, Japan and China. The problem of spectral emissivity measurement in the laboratory has been solved by now. However, it is limited to study on-line emissivity measurement apparatus, which is eager to be obtained in modern military technology, material science and energy science.In this dissertation, multi-spectral thermometry and emissivity new algorithm, the development of multi-spectral thermometer, choice of front reflector apparatus and optimization design have been researched thoroughly. The experiment on the basis of experimental platform has been made. Expected experimental results have been abtained, the main research contributions of this dissertation are as follows:1. On the aspect of the algorithm of multi-spectral on-line emissivity measurement theory, the brightness temperature model and reference temperature model utilizing neural network algorithm have been simulated, and the results coincide with the data provided by Dr. F.Righini.2. Emissivity on-line measurement apparatus based on front reflector apparatus and optical fiber multi-spectral apparatus, experimental auxiliary and calibration apparatus have been developed. Reflector, multi-wavelength based on optical fiber, heater and control apparatus have been designed. The spectral scope of 0.4~1.1μm and non-contact emissivity measurement in the temperature scope of 700~2000℃have been achieved, the error of experimental results is less than 0.03.3. Reflector's theory model with the method of solid angle proportion divided has been constructed, the relation between cavity effective emissivity of reflector and material surface emissivity has been calculated, through the constructing model for combination apparatus of multi-wavelength based on optical fiber and reflector, the calculation method that fits this combination apparatus has been obtained.4. Ultilizing this emissivity on-line measurement apparatus, stainless metal and silicon carbide's spectral emissivity have been measured. The measurement error has been analyzed and the results indicate that the emissivity measurement apparatus satisfys the demand of on-line emissivity measurement.The achievement of this dissertation has established foundation for the research of pratical on-line emissivity measurement in the future.