A Measuring Method of Thermal Diffusivity by Continuous Heating

Abstract

A new transient measuring method of thermal diffusivity by continuous heating of a slab-like specimen to obtain the temperature dependence of thermal diffusivity covering a wide temperature range in a short time, is investigated. The principle is based on the solution of equation of linear heat conduction and the thermal diffusivity is determined from the temperature response at the center face of the specimen heated continuously from both surfaces. The measuring conditions are determined by theoretical analysis. By comparing the linear solutions of the measuring principle with the non-linear solutions of the measurement obtained analytically or numerically, the heating conditions of the specimens under which the linear principle is satisfied within required accuracies are determined. Results of testing polyethylene up to the softening temperature with an apparatus based on the above conditions are shown.