A computer-controlled apparatus for thermal conductivity measurement by the transient hot wire method

The aim of this paper is to review the transient hot wire method for measurement of thermal conductivity, which is based on the measurement of temporal history of the temperature rise caused by linear heat source (hot wire) embedded in a test material. If a current is passed through the wire, the rise in temperature will be dependent, among other factors, on the thermal conductivity of the medium, surrounding the wire. Here the mathematical basis, as well as main modifications of the hot wire method — cross technique, resistance modifications with potential and compensated lead methods; hot wire probe method and parallel wire technique, are described and discussed. A fully automated computer-controlled transient hot wire apparatus is presented and tested, which allows measurement of thermal conductivity of solid, powder and granular materials at high temperatures.