Heat and mass transfer analysis and modeling in unsaturated ground soils for buried tube systems

Abstract

The performance of a single pipe carrying warm fluid buried in a medium wet sand is described in this paper. A finite element model is used to analyze the heat and moisture movement in a pipe-soil cross-section perpendicular to pipe length. System variables included are: pipe diameter, initial soil moisture concentration and temperature, and fluid-tube interface temperature. The time varying soil moisture concentrations and temperatures are graphically presented. Soil moisture profiles evolve at a slower rate than the temperature distribution functions. For fluid-tube interface temperature of 32°C and initial soil moisture concentration of 30%, moisture in pipe velocity will fall below 25% after 48 h.