Transport in Porous Media

, Volume 41, Issue 2, pp 137–147

Thermal Conductivity of Soils at Very Low Moisture Content and Moderate Temperatures

  • V.-R. Tarnawski
  • W. H. Leong
Article

Abstract

An analysis of soil thermal conductivity data shows that, at very low moisture content, this property first varies insignificantly and then begins to increase from a certain critical moisture content, whose value tends to depend on clay mass fraction. Two simple models evaluating the critical moisture content were developed; the first one is a fraction of the permanent wilting point; the second one is a simple linear function dependent on clay mass fraction. An insignificant variation of soil thermal conductivity is observed at 20°C, within a water pressure head ranging from 1 × 103 to 1 × 103 m, while for higher temperatures (45–50°C) from 5000 to 100000 m. Three extensions of the enhanced thermal conductivity model by Sundberg, namely SUN-1, SUN-2 and SUN-3, were proposed and tested. They produce an average root mean square error of 27%, 24% and 30%, respectively, with respect to experimental data. SUN-1and SUN-2 predictions could be further improved if better estimates of thermal conductivity at the dry state and the permanent wilting point were provided. SUN-3 is a simple model which does not require information about the PWP and critical moisture content. All SUN models have a potential for implementing the latent heat transfer component.

predictive models soils thermal properties thermal conductivity 

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Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • V.-R. Tarnawski
    • 1
  • W. H. Leong
    • 2
  1. 1.Saint Mary's UniversityCanada
  2. 2.Department of Mechanical EngineeringRyerson Polytechnic UniversityTorontoCanada

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