Fully Coupled Analysis of Heat, Moisture, and Air Transfer in Unsaturated Soil

Thomas, Hywel Rhys; Sansom, Michael

doi:10.1061/(asce)0733-9399(1995)121:3(392)

Cited by 124 publications

(53 citation statements)

References 16 publications

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“…In addition, considering the mechanical and chemical equilibriums, a certain amount of dry air will dissolve into liquid according to Henry's law. Considering the above four effects, the balance equation for dry air may be presented as [Thomas and Sansom, 1995] …”

Section: Dry Air Equationmentioning

confidence: 99%

“…Nevertheless, the neglect of airflow in the PdV model restrains the analysis of the advective effect on evaporation. A two-phase heat and mass flow model can be used to investigate the vapor transport induced by airflow and has been applied in many engineering fields, such as geothermal engineering [Thomas et al, 1998;Thomas and Sansom, 1995], drying engineering [Kowalski, 2008], and environmental engineering [Pruess, 2004;Schrefler, 2004]. However, no particular attention has been paid to examining the advective effect on evaporation.…”

Section: Introductionmentioning

confidence: 99%

“…According to the definition of capillary potential, h could be expressed as the difference between the pore air pressure and the pore water pressure [Gray and Hassanizadeh, 1991;Fredlund and Rahardjo, 1993;Thomas and Sansom, 1995]:…”

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confidence: 99%

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A simulation analysis of the advective effect on evaporation using a two‐phase heat and mass flow model

Zeng

Wan

et al. 2011

Water Resources Research

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[1] The concept of enhanced vapor transfer in unsaturated soils has been questioned for its reliance on soil temperature gradient, which leads to consideration of other mechanisms of vapor transfer, e.g., advective vapor transfer due to soil air pressure gradient. Although the advective flux is an important portion of evaporation, there is a lack of knowledge of its effect on evaporation. In order to assess the dependence of evaporation on the soil air pressure gradient, a vertical one-dimensional two-phase heat and mass flow model is developed that fully considers diffusion, advection, and dispersion. The proposed model is calibrated with field measurements of soil moisture content and temperature in the Badain Jaran Desert. The proposed model is then used to investigate the advective effect in both low-and high-permeability soils. The advective effect is reflected by underestimating evaporation when the airflow is neglected and is more evident in the low-permeability soil. Neglecting airflow causes an underestimation error of 53.3% on the day right after a rainfall event in the low-permeability soil (7.9 Â 10 À4 cm s À1) and 33.3% in the high-permeability soil (2 Â 10 À3 cm s À1). The comparisons of driving forces and conductivities show that the isothermal liquid flux, driven by the soil matric potential gradient, is the main reason for the underestimation error.Citation: Zeng, Y., Z. Su, L. Wan, and J. Wen (2011), A simulation analysis of the advective effect on evaporation using a two-phase heat and mass flow model, Water Resour.

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Section: Dry Air Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A simulation analysis of the advective effect on evaporation using a two‐phase heat and mass flow model

Zeng

Wan

et al. 2011

Water Resources Research

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“…Dry air transport in unsaturated soil is originally taken into account in STEMMUS, and the balance equation can be written (Thomas and Sansom, 1995) as…”

Section: Yu Et Al: the Effect Of Different Et Methods On Portrayimentioning

confidence: 99%

The effect of different evapotranspiration methods on portraying soil water dynamics and ET partitioning in a semi-arid environment in Northwest China

Zeng

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Different methods for assessing evapotranspiration (ET) can significantly affect the performance of land surface models in portraying soil water dynamics and ET partitioning. An accurate understanding of the impact a method has is crucial to determining the effectiveness of an irrigation scheme. Two ET methods are discussed: one is based on reference crop evapotranspiration (ET 0 ) theory, uses leaf area index (LAI) for partitioning into soil evaporation and transpiration, and is denoted as the ET ind method; the other is a one-step calculation of actual soil evaporation and potential transpiration by incorporating canopy minimum resistance and actual soil resistance into the Penman-Monteith model, and is denoted as the ET dir method. In this study, a soil water model, considering the coupled transfer of water, vapor, and heat in the soil, was used to investigate how different ET methods could affect the calculation of the soil water dynamics and ET partitioning in a crop field. Results indicate that for two different ET methods this model varied concerning the simulation of soil water content and crop evapotranspiration components, but the simulation of soil temperature agreed well with lysimeter observations, considering aerodynamic and surface resistance terms improved the ET dir method regarding simulating soil evaporation, especially after irrigation. Furthermore, the results of different crop growth scenarios indicate that the uncertainty in LAI played an important role in estimating the relative transpiration and evaporation fraction. The impact of maximum rooting depth and root growth rate on calculating ET components might increase in drying soil. The influence of maximum rooting depth was larger late in the growing season, while the influence of root growth rate dominated early in the growing season.

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“…Lewis et al [7][8][9] developed the finite element model and its solution procedure for heat transfer coupled with nonlinear hydro-mechanical process in saturated and unsaturated porous media. Thomas et al [10][11][12][13] presented a fully coupled THM mathematical model based on the experimental results and previous work they achieved. They devoted much efforts on numerical modelling of coupled THM processes in porous media and its applications to environmental engineering problems, particularly to the numerical simulation of the THM behaviour in engineered clay barriers.…”

Section: Introductionmentioning

confidence: 99%

A thermo-hydro-mechanical constitutive model and its numerical modelling for unsaturated soils

Charlier

et al. 2004

Computers and Geotechnics

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A thermo-hydro-mechanical (THM) constitutive model for unsaturated soils is proposed in this paper based on the existing models. The influences of temperature on the hydro-mechanical behaviour in unsaturated soils are described in the model. Particularly, the thermal softening phenomenon, i.e. decreases in value of the pre-consolidation pressure and in critical value of the suction of the SI (suction increasing) curve with heating process, is quantitatively modelled by using the experimental data and previous work [J. Geotech. Eng. ASCE 116 (12) (1990) Barcelona, Spain]. Numerical modelling of the proposed THM model has also been implemented within the finite element code LAGACOM. Finally, the comparisons of the results obtained from the numerical modelling of the constitutive behaviour with existing experimental results show that the present model can simulate the thermo-hydro-mechanical behaviour in unsaturated soils with satisfaction. Some other numerical results given in the paper also validate the versatility and applicability of the present constitutive model.

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Fully Coupled Analysis of Heat, Moisture, and Air Transfer in Unsaturated Soil

Cited by 124 publications

References 16 publications

A simulation analysis of the advective effect on evaporation using a two‐phase heat and mass flow model

A simulation analysis of the advective effect on evaporation using a two‐phase heat and mass flow model

The effect of different evapotranspiration methods on portraying soil water dynamics and ET partitioning in a semi-arid environment in Northwest China

A thermo-hydro-mechanical constitutive model and its numerical modelling for unsaturated soils

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