Surface Temperature Measurement Using Infrared Radiometer. (2nd Report, Applicability of Pseudo Gray Body Approximation).

In the previous study, we clarified various fundamental characteristics, such as radiation temperature, radiosity coefficient, emissivity and reflectivity, of 3 kinds of infrared radiometers to measure temperature distribution on a non metal surface, on which gray-body approximation is applicable. However, gray-body approximation is not always applicable to all material surfaces. For instance, its approximation is not appropriate on metal surfaces owing to the effect of the directive and spectral properties. Therefore, in the present study, applicability of pseudo-gray-body approximation on a metal surface enclosed by black body walls at constant temperature was studied and analyzed to establish a simpler and more general measurement technique using an infrared radiometer.