A. Griesinger et al., Investigation on measurement accuracy of the periodic hot-wire method by means of numerical temperature field calculations, INT COMM HE, 26(4), 1999, pp. 451-465
Citations number
9
Categorie Soggetti
Mechanical Engineering
Journal title
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
The periodic hot-wire method is an appropriate means for the determination
of the thermal diffusivity alpha and thermal conductivity lambda. A thin pl
atinum wire in a sample is heated by a sinusoidal alternating current. The
resulting thermal waves penetrate into the surrounding sample. The thermal
diffusivity alpha and the thermal conductivity lambda, of the sample can be
calculated by analysing the amplitudes and the phase-lags of the waves and
applying the Fourier equation. In order to derive the evaluation procedure
for alpha and lambda the temperature field in the sample is calculated ana
lytically under the assumption, that the platinum wire represents a perfect
, infinitly extended line heat source. This assumption can only be approach
ed and thus measurements must deviate from theory. These deviations were de
termined by numerical calculations of the temperature field considering the
real geometry of the platinum wire. The measurement accuracy and the optim
um frequency range of the periodic hot-wire method has been obtained by com
paring the numerically and analytically calculated temperature fields. (C)
1999 Elsevier Science Ltd.