Modeling of Radiation Heat Transfer in Glass Melts

Abstract

Glass furnaces combust fuels and oxidizers so that the batch will be melted and the molten glass refined. The heat generated from the combustion space is mainly transmitted to the glass melt by radiation. This radiation is strongly wavelength dependent due to the nature of soot and carbon dioxide/water emission. Conventional wisdom indicates that the transport of radiation in molten glass can be modeled using a diffusion approximation. However, for many glass compositions, this approximation may not be justified since there is appreciable transmission of thermal energy at lower wavelengths. To account for the detailed transmission of radiation in the glass melt, a recently developed radiation model was incorporated into a glass melt simulation. This spectral model rigorously conserves emitted and absorbed energy throughout the melt and the surrounding walls. The glass melt flow simulation is a multi-phase reacting flow computational fluid dynamic code that accounts for the solid batch material, liquid glass, and gas bubble. This paper presents details of the radiation model along with results depicting the effect of the detailed radiation transmission on the glass melt flow field.