G0601-4-2 Evaluation of infrared spectral diffusive transmission characteristic and attenuation coefficient of thermal insulations

Abstract

In order to investigate the radiation heat characteristics of thermal insulations, we have developed a new apparatus to measure the diffusive reflectance and transmittance at a temperature range from room temperature to 1000 ℃ in the wavelength range from 1.28 to 25 pm. In this study, the diffusive transmittances of thermal insulation (Alumina-silica blanket) were measured. Those diffusive transmittances were less 1% without vertical transmission angle. Furthermore, the attenuation coefficient to the surface density was obtained by using the hemispherical transmittance calculated from the diffusive transmittance in the wavelength range from 2 to 10 μm. Alumina-silica blanket has two attenuation coefficients; one is about 40.3 m^2/kg in the surface density range below 0.05 kg/m^2, the other is about 14.2 m^2/kg in the surface density range above 0.05 kg/m^2.