Sensitivity of a Coupled Heat and Mass Transfer Model for Unsaturated Soils


A new form of heat and moisture transfer relations in unsaturated porous media are introduced and then a sensitivity analysis of thermal properties is presented. The proposed model is defined with the effects of combined volumetric moisture content changes and temperature gradients. Thus at this formulation, there are introduced some new material parameters for each obtained equation which are related with thermodynamic specifications of soil and the soil-water characteristic curve. Hence, the influences by changing of each material parameter is so important in thermal behavior of wet soils, that in this paper will discussed on three kinds of them separately. The volumetric thermal and isothermal capacity, diffusivity and conductivity coefficients are defined from mass and heat balanced equations, investigated by some thermal graphs. Meanwhile, the suction derivatives which are the main parameters affected on thermal and isothermal coefficients, is obtained by examining the retention curve. As a result, it was found that the volumetric water content and specific heat capacity are the main factors could be effective to generating the thermal and isothermal diffusivities and conductivities in representing of coupled behavior of heat and moisture in unsaturated porous media. This sensitivity studies allows for a more accurate prediction of the soil temperature field and the circulating fluid temperature profile, and also can be helped to determine the accurate perception of the thermal and isothermal material parameters.

  • Abstract
  • Key Words
  • 1. Introduction
  • 2. Governing Equations
  • 3. Sensitivity Analysis
  • 4. Summaries
  • References

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