Determination of Opaque Material Temperature from the Spectral Distribution of Emitted Radiation Intensity with Unknown Emissivity

Abstract

The thermodynamic temperature of an opaque material with unknown emissivity was determined from the recorded distribution of spectral intensities of the emitted radiation. The initial system of equations was derived in the logarithmic form in accordance with the Planck formula. At the first stage, the spectral dependence of the material emissivity was investigated with a special function—relative emissivity. Based on the analysis of spectral dependences of this function at different reference temperatures, a parametric model for the material emissivity was chosen. At the second stage, the desired parameters of the chosen model of spectral emissivity and the thermodynamic temperature of the material were determined. An example of the determination of a temperature of a tungsten sample from the spectral distribution of emitted radiation intensities is given. A method for narrowing the range, which includes the thermodynamic temperature of the material, is presented.