Determining the thermal properties of materials with complex structures is still a
major engineering challenge today. The well-known heat pulse experiment can be used
to determine the thermal diffusivity by measuring the temperature history as a thermal
response for a fast excitation. However, the evaluation of the measurements can be
challenging, especially when dealing with non-homogeneous samples. The thermal behavior
of such heterogeneous materials may exhibit a response including two-time scales.
Therefore, the Fourier equation is not necessarily applicable. The simplest possible
alternatives are the 2-temperature models the Guyer–Krumhansl and Jeffreys heat equations.
In the present paper, we focus on the interpretation of the Jeffreys heat equation;
studying its analytical solution, we present a fitting method for determining the
unknown parameters. We also discuss its relation with the other two heat equations,
and we offer an interpretation of how to characterize the transient response of heterogeneous
materials.
