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Three‐dimensional heat, moisture and air transfer in unsaturated soils
Author(s) -
Thomas H. R.,
Rees S. W.,
Sloper N. J.
Publication year - 1998
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/(sici)1096-9853(199802)22:2<75::aid-nag909>3.0.co;2-k
Subject(s) - heat transfer , thermal conduction , water content , moisture , finite element method , convection , mechanics , thermal conductivity , soil water , airflow , geotechnical engineering , thermodynamics , environmental science , meteorology , soil science , engineering , mechanical engineering , physics
A new three‐dimensional numerical model of coupled heat, moisture and air transfer in unsaturated soil is presented. In particular, the model accommodates moisture transfer in the form of liquid and vapour flow and heat transfer arising from conduction, convection and latent heat of vaporization. The bulk flow of dry air and the movement of air in a dissolved state are also included. The theoretical basis of the model, the finite element solution of the spatial terms and finite difference solution of the temporal terms are briefly presented. Attention is focused on the verification of the new numerical solution. This is achieved via comparisons with independent solutions of heat, moisture and air transfer in an unsaturated soil. The physical problem considered includes the highly non‐linear hydraulic properties of sand. Thermal conductivity is also included as a function of soil moisture content. Excellent correlation of results is shown thus providing confidence in the new model. The new model is also applied to a number of test cases which illustrate the need for the development of a model which can fully include three‐dimensional behaviour. In particular, three applications are presented each increasing in complexity. The first application illustrates three‐dimensional heat transfer. This particular application is verified against existing commercial finite element software. Subsequent applications serve to illustrate how the coupled processes of heat moisture and air transfer combine to yield three‐dimensional problems even within a simple geometric domain. Visualization of three‐dimensional results is also addressed. © 1998 by John Wiley & Sons, Ltd.