A new statistical approach to thermal conductivity evaluation of transient hot wire (THW) and transient hot strip (THS) signals
Reiner Stosch, Ulf Hammerschmidt
A new approach to thermal conductivity evaluation derived from transient hot-wire (THW) and transient hot-strip (THS) experiments is presented. Although based on the widely used quasilinear approximation to the working equation, the new method no longer requires precise location of the evaluable part of the signal but can rather be applied to the entire curve monitored. The two-step procedure involves assigning a unique thermal conductivity value, λi, to each data point observed, followed by statistical treatment of the resulting set of values. The thermal conductivity of the material under test is then obtained from a distribution model applied to λi as the location of the most probable value,λm. Since no special action by the experimenter is required, the new method is suitable for integration into the instrument’s evalu- ation software. The evaluation procedure was first verified on finite-element-model simulated THW/THS signals and has then been successfully applied to experimental data on water (THW) and Pyrex (THS).