Study of Quasi-Steady State Method for Thermal Conductivity Measurement

Abstract

Thermal conductivity measurement by steady state comparative-longitudinal heat flow method takes about 4000 s until the temperature becomes steady state, and several tests are necessary to obtain the temperature dependency of the thermal conductivity. On the other hand, measurement time can be greatly shortened by quasi-steady state method in which the transient temperature variation data are applied to the equation used in the conventional steady state method to obtain the thermal conductivity. This quasi-steady state method gives us the temperature dependency of thermal conductivity by only one measurement. In this research, we conducted fundamental verification of measurement accuracy and measurable time of the quasi-steady state method with experiment and numerical analysis using specimens made of aluminum with large thermal conductance and acrylic resin with small thermal conductance. As a result, it has been clarified that the measurable time becoming the measurement accuracy less than 10% is about 100 s for aluminum specimen and is about 1000 s for resin specimen, so measurement time can be shortened from about 1/4 to 1/40 times compared to steady state method.