DEVELOPMENT OF A THERMAL CONDUCTIVITY MEASURlNG APPARATUS FOR NON-METALLIC SOLIDS

Abstract

A thermal conductivity measuring apparatus for non-metallic solids (poor conductors) based on modified Lee's disc method has been designed, constructed and tested. Specimens of concrete, glass, portland cement, asbestosand corrugated cardboard were prepared in the form of discs each of diameter 50mm but of varying thicknesses. The average thermal conductivity values obtained for these specimens over a heat source temperature range of 25°C- 60°C were found to be 1.285, 0.737, 0.327, 0.121 and 0.072 Wm-1 K-1 respectively. The values of thermal conductivity obtained for the various specimens were compared with those given in the literature for the purpose of determining the effectiveness of the apparatus. The differences in values ranged between 1.55- 11.03 per cent thus giving credence to the effectiveness of the apparatus.