Radiometric thermometry of high temperature alloy surfaces incorporating emissivity variation constraints

Abstract The surface radiation characteristics of high-temperature alloy materials are influenced by various factors, which can decrease the accuracy of the temperature measurement. In this paper, a surface radiation thermometry method of high temperature alloy incorporating emissivity variation constraints is proposed to accurately describe the trend of emissivity variation with wavelength by constructing an emissivity variation constraint model based on ridge estimation. The golden sine algorithm and the dynamic weight factor are further used to improve the whale optimisation algorithm to achieve high-precision temperature solution of the objective function after the emissivity variation constraint. The trends before and after emissivity correction are analysed by simulation, and the experimental validation shows that the maximum temperature measurement error of the algorithm is no more than 0.3 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">%</mml:mi> </mml:mrow> </mml:math> , and the average time is 0.057 s. The algorithm shows good accuracy and stability in the radiation thermometry of high-temperature metal samples, which verifies the feasibility and high efficiency of the method in practical applications.