EXPERIMENTAL APPARATUSES FOR RADIOMETRIC EMISSIVITY MEASUREMENTS AND THEIR APPLICATIONS

摘要

Two experimental apparatuses for the measurement of radiometric emissivity of metals have been developed. The purpose of the development of the apparatuses is to study the behaviour of the emissivity of a metal and to contribute to the creation of new radiation thermometry to negate the emissivity problem. The one of the developed apparatuses is used in controlled atmosphere and the other is applied during heating in air. The former possesses some features that it keeps a metallic sample under specific conditions such as vacuum, oxidizing and deoxidizing atmosphere. The maximum temperature and the maximum diameter of the specimen are 1023 K and 88 mm, respectively. Using the apparatus, spectral (from visible to 10 μm infrared wavelengths), directional (normal and 80°) and polarised emissivities (p-polarised and s-polarised) of metals can be measured and can be utilised to investigate the behaviour of the emissivity of the specimen. The latter is composed of several optical fibre systems, which connect sensors with polarisers and filters for simultaneous measurements of spectral and directional radiances, and mostly is used during oxidizing process of the surface of a metal when it is heated in air. The maximum temperature and maximum diameter of the sample are 1273 K and 50 mm, respectively. Using this apparatus, spectral, directional (from normal to nearly 85° at zenithal directions) and polarised emissivities can be measured as well. In this paper, the concrete design of the apparatuses is described and some examples of measurements of emissivities under some specific conditions are introduced.