Effect of temperature distribution on moisture flow in porous materials

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TypeArticle
Journal titleTransactions, American Geophysical Union
Volume39
Issue4
Pages676680; # of pages: 5
AbstractSeveral experirnenters have observed moisture flow rates through porous materials under a temperature gradient, which are many times the calculated rates based on vapor diffusion. To investigate this discrepancy, a temperature gradient was applied across an enlarged model of a particular, high-quartz wet sand, and the temperature distribution within the pore spaces was measured. For the 'air-dry condition' of the model, the average temperature gradient in the pore spaces was six times the over-all applied gradient. Approximately this same ratio exists, therefore, between the respective vapor pressure gradients. It is proposed that tlie flow mechanism consists of multiple vapor diffiusion and liquid flow steps in series, the resistance to flow in the liquid phase being negligible, so that the flow rate is determined by the vapor pressure gradients in the pore spaces. The fact that these gradients are of the order of six times the over-all gradient previously used to calculate the flow rate at least partially explains the discrepancy.
Publication date
LanguageEnglish
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedNo
IdentifierDBR-RP-68
NRC number4748
6944
NPARC number20358811
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Record identifier320a216a-4254-4d2c-83dd-a112d18927c6
Record created2012-07-20
Record modified2016-05-09
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