Transient Hot Wire Method to Measure the Thermal Conductivity of Solid Materials

Abstract

A hot wire should be put in the interfacial space between a couple of solid materials. The clearance at the interface becomes the third phase which is not considered in the theory of hot wire method, and would cause some errors in the measurment of thermal conductivity. This paper gets solutions of heat conduction problem of the solids with a thin interfacial clearance, with the aid of heat source theory, and with the aid of numerical calculation. It is found and experimentally proved that the temperature increase rate develops slowly on account of the existance of clearance but it reaches finally the rate which indicates the right thermal condictivity of solid material. Some means to make the temperature development fast are discussed.