An Analysis of Heat Transfer Coefficient for Unsaturated Soils from Radial and Unidirectional Experiments

Heat transfer coefficients involving radial and unidirectional experiments have been analysed under unsaturated soil conditions. Former experiments made use of the cylindrical heat probe, whereas, in the latter case time dependent soil temperature distributions were studied in laboratory soil columns. The results showed that the data were not described adequately by the two theories because of the inherent limitations in the two methods. The values for the coefficient of thermal diffusivity evaluated under unidirectional experiments were found to be 3.7 times greater than those obtained under radial heat flow experiments where short measuring time intervals with relatively lower temperature gradients were involved.