Long/short hot-probe method for determining thermophysical properties

Abstract

The traditional hot-probe method, which is developed from the transient hot-wire method, can only be applied to determine thermal conductivity. This kind of method is based on the idealized 'one-dimensional radial heat flow' model. As a matter of fact, the finite length influence of a hot probe on measurement is remarkable when the hot probe is not sufficiently long. The corrected term of finite length for a hot probe is nonlinearly dependent on the thermal diffusivity of the measured sample and the length of the hot probe. In this work the long/short hot-probe method (LSHPM) is developed which can simultaneously determine the thermal conductivity, thermal diffusivity and specific heat of the measured sample. The basic principle of the LSHPM is analysed, the measurement procedure is described, and the relative differences of the measurement results are compared with the values recommended by the Thermophysical Properties Research Center, which are 0.7%, 1.3% and 2.0% for thermal conductivity, thermal diffusivity and specific heat respectively.