INDIRECT, WITH RESPECT TO THE NONLINEARITY EQUATION, MEASUREMENT OF THE RADIATING CAPACITY AND TEMPERATURE OF OPAQUE MATERIALS

This work is aimed at improving metrological characteristics and expanding the areas of application of optical thermometry of opaque objects, including the method of two-color compensative pyrometry with an apriori averaged adjustment previously developed by the authors. A nonlinearity equation has been obtained that connects the nonlinearity coefficient of spectral distribution of directional emissivity on an average wavelength of the registered radiation with a value of spectral directional emissivity on one of boundary wavelengths via the measured brightness temperature on three wavelengths. It has been established that the number of numerical solutions of the equation at various qualitative and quantitative characteristics of spectral distributions is from 1 to 3. To determine a correct solution, analytical and algorithmic methods of its identification have been proposed. On the basis of the equation, linear, two-range, and parabolic methods of determining spectral directional emissivity have been developed. It has been established that the methodological errors of temperature measurements by the two-range method are 5–7 times lower than the errors of the linear method. For signifi cant nonlinearities, the parabolic method errors are 1.13–1.24 times lower than the linear method errors. In this case, for the two-range method, the combined errors for two-color compensative pyrometry are lower than the errors for spectral ratio pyrometry and for energy pyrometry 110 and 7 times respectively
   
Author:  L. F. Zhukov, D. A. Petrenko
Keywords:  nonlinearity equation and coeffi cient, spectral distribution of directional emissivity, object temperature, brightness temperature, parabola
Page:  266