An experimental and theoretical study of radiative and conductive heat transfer in nongray semitransparent media

Abstract

One dimensional temperature profiles and heat fluxes within a slab of molten glass were measured experimentally. The glass slab was contained in a platinum foil lined ceramic tray inside a high temperature furnace. An optical method of temperature measurement was developed in which a helium-neon laser beam was directed along an isothermal path through the glass. The attenuation of the beam was a strong function of temperature and was used to evaluate the local temperatures within the glass slab. In order to perform a theoretical analysis the spectral absorption coefficient of the glass was measured between .6328 microns and 2. 75 microns from 2000 0F to 23000F. Two analyses were performed; one for a diffuse platinum-glass boundary and the other for a specular boundary. The experimentally measured temperature profiles and heat fluxes agreed with the predicted profiles within 50F and the heat fluxes to within ten percent.