Thermal conductivity of heat-absorbed soda-lime-silicate glasses at high temperatures

Abstract

Thermal conductivity, k, of several heat-absorbed soda-lime-silicate glasses has been measured by a transient needle probe method in the temperature range from 303 to 1473 K in order to obtain fundamental data for the float glass production process. Five cylindrical samples 100 mm in diameter and about 120 mm in height are used for the measurement. Samples used are ordinary clear float glass (CFL), bronze (BFL), gray (GFL), blue (HFL), and green (MFL) glasses. The physical properties of these samples are as follows: spectral transmittance (visible, 5 mm thickness) 89.3%, 63.9%, 64.3%, 77.5%, and 77.0%, respectively. The k values of these samples are measured at a set of temperatures: 303, 573, 773, 973, 1073, 1173, 1273, 1373, and 1473 K, by a transient probe method previously developed. The measured k values increase with rise of temperature in the range from room temperature to 1473 K. The effect of thermal radiation on the k values is discussed. It appears that the thermal conductivity is essentially unaffected by the addition of heat-absorbing components.