RADIATIVE-OPTICAL AND THERMOPHYSICAL CHARACTERISTICS OF FIBROUS SILICA-BASED HEAT INSULATION

Results of computational and experimental determination of spectral optical parameters, i.e., the indices of scattering and absorption, of two types of silica-based fi brous heat insulation have been given. Materials fabricated from quartz and silica fi bers have been considered. The optical parameters in the range of wavelengths 1–4.7 μm were determined by solution of the inverse problem from experimental data for the spectral coeffi cient of total refl ection. The inverse problem was solved by minimization of the residual functional between the experimental and calculated spectra of refl ection coeffi cients of the materials′ layers of several thicknesses. The spectra of the total-refl ection coeffi cients were measured on a Fourier spectrometer with an integrating sphere in the range of wavelengths 1–18 μm. To calculate the spectral refl ection coeffi cient, use was made of the invariant embedding method. By the spectral optical parameters, the authors have assessed the radiative thermal conductivity in the Rosseland approximation and the integral emissive power of material layers of different thicknesses in the range of temperature 20–1100o C. The calculated radiative thermal conductivity has been compared with the experimental data on the effective thermal conductivity measured by the method of a quasi-stationary thermal regime.
   
Author:  R. A. Mironov, V. O. Gaidenko, M. O. Zabezhailov, O. V. Tomchani, V. V. Cherepanov, and O. M. Alifanov
Keywords:  optical properties of fi brous heat insulation, partially transparent materials, inverse problems of radiation transfer, radiative-conductive heat transfer
Page:  1600