Study on Temperature Measurement Errors and Correction Method of Inner Surface of Cavity-Like Objects With Directional Reflection Characteristics

The thermal radiation reflection properties of real material surfaces tend to be directional, which leads to inaccuracies in existing methods for measuring the diffuse inner surface temperature of cavity-like objects. In this article, we propose a method for measuring the temperature at the inner surface of cavity-like objects that describes the interreflection based on the bidirectional reflectance distribution function (BRDF) and on the Monte Carlo ray-tracing method (MCM). The effects of measurement angles and surface roughness on temperature measurement errors have been analyzed through simulation calculations and experiments. The results show that the inner surface structure and reflection characteristics make the error change at different measurement angles. Compared to the actual methods in use, the results obtained for the proposed method for the inner surface with directional reflection allow a reduction in the maximum relative error from 14.2% to 0.8%.