Abstract
The thermal conductivity of polymethyl methacrylate (PMMA) and borosilicate crown glass BK7 has been studied. The transient hot-wire technique has been employed, and measurements cover a temperature range from room temperature up to 350 K for PMMA and up to 500 K for BK7. The technique is applied here in a novel way that minimizes all remaining thermal-contact resistances. This allows the apparatus to operate in an absolute way and with very low uncertainty. The method makes use of a soft silicone paste material between the hot wires and the solid under test. Measurements of the transient temperature rise of the wires in response to an electrical heating step over a period of 20 μs up to 5 s allow an absolute determination of the thermal conductivity of the solid, as well as of the silicone paste. The method is based on a full theoretical model with equations solved by a two-dimensional finite-element method applied to the exact geometry. At the 95% confidence level, the standard deviations of the thermal conductivity measurements are 0.09% for PMMA and 0.16% for BK7, whereas the standard uncertainty of the technique is less than 1.5%.
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M. J. Assael M. Dix K. Gialou L. Vozar W. A. Wakeham (2002) Int. J. Thermophys. 23 615 Occurrence Handle10.1023/A:1015494802462
M. J. Assael K. Gialou (2003) Int. J. Thermophys. 24 667 Occurrence Handle10.1023/A:1024080030912
M. J. Assael K. Gialou (2003) Int. J. Thermophys. 24 1145 Occurrence Handle10.1023/A:1025069405106
M. J. Assael K. Gialou (2004) Int. J. Thermophys. 25 397 Occurrence Handle10.1023/B:IJOT.0000028477.74595.d5
Guide to the Expression of Uncertainty in Measurement (International Organisation for Standardisation, Genova, 1995).
R. P. Tye and D. R. Salmon, “Thermal Conductivity of Reference Materials: Pyrex 7740 and Polymethyl Methacrylate,” NPL report(2003).
S. Rudtsch U. Hammerschmidt (2004) Int. J. Thermophys. 25 1475 Occurrence Handle10.1007/s10765-004-5752-y
S. Rudtsch, R. Stosch, and U. Hammerschmidt, in Proc. 16th Europ. Conf. Thermophys. Props., London (2002).
M. L. V. Ramires C. A. Nietode Castro R. A. Perkins Y. Nagasaka A. Nagashima M. J. Assael W. A. Wakeham (2000) J. Phys. Chem. Ref. Data 29 133 Occurrence Handle10.1063/1.556057
T. Boumaza J. Redgrove (2003) Int. J. Thermophys. 24 501
Ĺ. Kubičár V. Bohac (2002) High Temp. High Press 34 135 Occurrence Handle10.1068/htwu134
N. Lockmuller, J. Redgrove, and Ĺ. Kubičár, High Temp. High Press. 35/36:127 (2003/2004).
Ĺ. Kubičár V. Vretenár U. Hammerschmidt (2005) Int. J. Thermophys. 26 507
H. P. Ebert, ZAE Bayern. 31 (2002).
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Assael, M.J., Botsios, S., Gialou, K. et al. Thermal Conductivity of Polymethyl Methacrylate (PMMA) and Borosilicate Crown Glass BK7. Int J Thermophys 26, 1595–1605 (2005). https://doi.org/10.1007/s10765-005-8106-5
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DOI: https://doi.org/10.1007/s10765-005-8106-5