Transient heat and mass transfer in soils

Abstract

Transient heat and mass transfer in soil surrounding a buried heat source are considered. One dimensional (spherical) models are developed to predict the coupled heat and moisture migration phenomena. Numerical solutions of the exact formulation are given. In addition, two types of closed-form solutions are derived employing approximate models. Experimental measurements are presented for two disparate soil types — a well-graded loam (slow hydraulic response) and sand (more rapid hydraulic response). Predicted and measured temperature variations at the heat source surface are compared. In all cases the numerical solution of the exact formulation agrees with the experimental data reasonably well. The closed-form solutions deviate somewhat from the measurements, but are shown to be useful for obtaining approximate predictions in a simple manner.