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Probe for thermal conductivity measurement of dry and moist materials

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Abstract
The development of the probe or transient needle method for thermal conductivity measurement is reviewed. The theory of the method, sources of error and an improved technique for recording the probetemperature rise are described. Experimental results for dry silica aerogel show good reproducibilityand agreement with guarded hot plate measurements. Results for snow show a discontinuousvariation of conductivity during test. The measured conductivity continuously decreased during tests on moist sawdust and moist clay, suggesting a loss of moisture from the specimen in the vicinity of the probe. This is verified by calculation of the moisture migration caused by the large temperature gradients at the probe surface. It is suggested that temperature gradients, and hence moisture redistribution, in probe tests may be reduced by increasing the probe radius, contrary to the present trend in probe development which is toward smaller probes.
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  • Heating, Piping, Air Conditioning 30 (1 October 1958): 1–10.
LanguageEnglish
Peer reviewedYes
IdentifierDBR-RP-69
NRC numberNRCC 4938
NRC-IRC-6945
NPARC number20358786
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Record identifier553f25d0-9a49-4bc4-81ad-dbf7e217c7fa
Record created2012-07-20
Record modified2023-12-20
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