New Technologies of Symmetric-Wave Multicolor Thermometry and Their Metrological Characteristics

The influence of the optical characteristics of multicolor thermometry on its methodical and instrumental errors was investigated and, on the basis of the investigations performed, a new direction of symmetric-wave multicolor pyrometry of radiation, including linear and universal thermometric technologies, has been developed. It is shown that, in the case where the spectral distribution of the radiating capacity of a body is linear, the methodical error in determining its temperature by the method of linear symmetric-wave pyrometry of radiation is close to zero and is practically determined by the discreteness of the selection of temperatures of this body. The errors in measuring the temperature of the majority of materials, e.g., tungsten, by the method of linear symmetric-wave thermometry are 9.1–25.0, 5.9–6.8, and 2.4–3.3 times smaller than those given by classical energy, spectral-ratio and polychromatic pyrometries of radiation. The universal thermometry method proposed allows one to eliminate the methodical error, predominating in optical thermometry, in determining the temperatures of bodies with different linear and nonlinear spectral distributions of their radiating capacity. The residual instrumental error given by linear and universal symmetric-wave pyrometries of radiation of a body does not exceed the error in measuring its initial monochromatic radiation temperatures, i.e., 0.2–0.5%.