Experimental investigation on the effect of temperature on thermal conductivity of synthetic rock samples

Abstract

Abstract The effective thermal conductivity (ETC) plays an important role in many fields such as to solve basic geological problems, rock engineering, and utilization of heat energy; ETC is one of the most important thermo-physical properties of porous media. In this study, experiments on synthetic rock samples with different material mixture ratios under different operating temperatures are conducted to estimate the thermal conductivity property of the rock samples. The experiments were performed on synthetic samples with different ratios of gypsum, fine or medium sand, and water; 21 groups of tests were conducted under room temperature; another five groups of tests were conducted under different temperatures from 20 to 50 ° to assess the effect of temperature on thermal conductivity. According to existing studies and equations, thermal conductivity increases with an increase of sand content and a decrease in temperature. Moreover, based on our experiments, it is easy to identified a singularity on the general changing trend of thermal conductivity for each sample. Following our experimental results, we attempted to observe and interpret this alteration mechanism. According to the heat capacity theory in solid-state physics, this research provides new explanations for the above alteration.