Coupled heat and fluid flow in saturated-unsaturated compressible porous media

After conducting a thorough and critical review and synthesis of the literature, a set of equations is derived which describes heat and water transport in saturated-unsaturated, compressible porous media. These equations differ from those of Philip and de Vries (1957) and of de Vries (1958) in the following respects: a pressure-head (rather than water content) approach is employed, thus facilitating analysis of saturated and layered media as well as unsaturated soils; matric suction is consistently considered a function of temperature as well as water content; the medium is compressible; and the enhancement factors added to the thermal vapor diffusivity have been revised. This improved model of thermal vapor flow fits experimental data better for very dry and wet soils, and can be readily calibrated to data for a given soil.;A flexible isoparametric finite element model to solve transient two-dimensional problems is developed using the Galerkin technique. The model is validated against analytical solutions and a laboratory experiment. A monotonic interpolation scheme for representing the soil hydraulic characteristic curves is used with encouraging results. This method is more robust than cubic splines, and permits studies in dry soils which were previously numerically intractable.;Soil drying around heat sources, a practical problem encountered in earth heat storage applications, is studied via a laboratory experiment and computer simulation. The computer model is specially adapted to solve this highly nonlinear problem.