Rules of Emissivity Sample Choice in Multi-wavelength Pyrometry

Abstract

Since the theory for emissivity sample (example) is not clear, there exists unavoidable blindness in the sample choice for the true temperature determination (create emissivity samples using an assumption to calculate the true temperature according to brightness temperature and wavelength) in multi-wavelength pyrometry, resulting in considerable computational complexity and slow computing speed. In this article, the rules of the emissivity sample were first discovered through the theoretical analysis of the relationship between brightness temperature and emissivity, which provide a theoretical basis for the emissivity sample choice. Furthermore, the rules can reduce the sample size (amount) and improve the calculation speed. The effectiveness of the proposed rules was verified by measuring the true temperature of a solid rocket engine plume, in which the rules were applied to effectively select emissivity samples. The experimental results demonstrate that the computing speed of the true temperature determination can be improved by 5.73% to 48.64%.