Prof. D. N. Singh

S. KRISHNAIAH

Ph. D.
Indian Institute of Technology Bombay, Powai, India sankranthi@lycos.com

HEAT MIGRATION MODELING THROUGH GEOMATERIALS

In several real life situations and engineering projects, estimation of heat migration in geomaterials becomes mandatory, for efficient and safe engineering design of various structures. This can be achieved by determining thermal properties such as thermal resistivity, thermal diffusivity and specific heat of geomaterials, precisely and quickly. With this in view, a device named as 'thermal property detector' (THERMODET) has been developed and its efficiency in determining thermal properties of soils and admixtures used in cement and concrete, has been demonstrated. Efforts have also been made to develop a methodology to determine thermal properties of rocks using a thermal probe, which works on the principle of 'transient heat method'.
With increasing focus on the utility of geotechnical centrifuges for modeling and simulating various geoenvironmental and stability problems in geomechanics, efforts have also been made to study heat migration in different soils, compacted to different states. However, to avoid coupled phenomenon (migration of moisture due to the imposed thermal gradients) only dry and fully saturated states of the samples have been considered. With the help of 1-g and centrifuge tests, on a small geotechnical centrifuge, validity of the time scale factor and 'modeling of models' has been demonstrated. The study reveals that centrifugation does not influence thermal properties of the soils.
ANSYS 6.0 has been used to model heat migration in soils and the results have been validated with those obtained from different experiments. Based on this FEM model, 'time scale factor' for heat migration has also been validated. As such, this model can also be extended to study heat migration through rocks.