Estimation of Thermophysical Properties by the Spectral Method—Development and Evaluation

This paper reports the evaluation of a spectral technique for estimating thermophysical properties. It demonstrates that one can construct a virtual quasi-steady periodic experiment from a limited but properly selected set of transient non-periodic data. In the spectral domain, the phase angles of the responses at different locations relative to a periodic input signal depend on the thermophysical properties. For the purpose of this evaluation, the transient temperature responses to a surface heat flux input are analytically obtained at pre-selected sensor locations. The transient data are converted to periodic data, phase angles are computed, and thermophysical properties are estimated. All deviations from known property values due to numerical errors are reported.