Thermal conductivity of ceramic fibrous insulators at high temperatures

Abstract

The temperature and bulk density dependence of the thermal conductivity of commercial aluminosilicate fibrous insulators were studied by using the transient hot wire method. The thermal conductivity of ceramic fibrous insulators in both air and helium gas atmosphere increased with increasing bulk density. At high temperatures, however, the insulators with lower bulk density showed a higher thermal conductivity because of heat radiation. The following experimental relation between thermal conductivity λ and temperature θ was obtained for aluminosilicate fibruous insulators: λ=a exp(bθ). Relationships are given between the constants a and b and the bulk density. From the relation, the optimum bulk density of ceramic fibrous insulators can be calculated for each working temperature.