Prediction of thermal conductivity of granite rocks from porosity and density data at normal temperature and pressure:in situthermal conductivity measurements

To predict the thermal conductivity of granite rocks the existing mixing law and empirical models have been utilized. Due to the porosity dependence in all the existing models, ASTM standard methods have been utilized to measure the porosity including specific gravity and density. The chemical composition of these samples has been analysed using the x-ray fluorescence technique. Because of the complex structure of the specimens and non-availability of data, models depending on the strict geometrical structure like the shape, size, position of the constituent mineral and the arrangement of fluid in the samples have not been used. The predicted values of the effective thermal conductivity have been compared with the experimental measurements made on the samples, using Gustafsson's probe. The calculated thermal conductivities from various models are in agreement with the experimental observations. Simple correlations between the chemical composition and specific gravity, density and porosity are also reported.