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Thermal diffusivity measurements by Ångström's method in a fluid environment
Umeå University, Faculty of Science and Technology, Physics.
1991 (English)In: International journal of thermophysics, ISSN 0195-928X, Vol. 12, no 1, 191-206 p.Article in journal (Refereed) Published
Abstract [en]

Ångström's method has been used for measuring the thermal diffusivity, a, and the radial heat loss coefficients of a thin constantan wire, both in a vacuum and with the wire immersed in air and in four different liquids, and using temperature wave periods of 1 to 1000 s. The presence of a surrounding fluid medium causes errors of up to 90% in the measured values of a. It is shown that both the experimental errors and the radial heat loss coefficients can be accurately calculated using simple models, both at high and at low frequencies, and that a previously developed two-frequency model can be used to obtain accurate data for a even under these conditions, provided the frequency is high enough. We also present a new variety of Ångström's model, valid only at very low frequencies and with purely convective heat loss.

Place, publisher, year, edition, pages
1991. Vol. 12, no 1, 191-206 p.
Keyword [en]
Thermal diffusivity, high pressure, fluid medium, heat loss, experimental methods, Ångström's method
National Category
Condensed Matter Physics
Research subject
URN: urn:nbn:se:umu:diva-26637DOI: 10.1007/BF00506131OAI: diva2:273074
Available from: 2009-10-20 Created: 2009-10-20 Last updated: 2010-02-02

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