Temperature Dependence of Thermal Properties of Sands across a Wide Range of Temperatures (30–70°C)
- Kathleen M. Smits ,
- Toshihiro Sakakiab,
- Stacy E. Howingtonc,
- John F. Petersc and
- Tissa H. Illangasekarea
Center for Experimental Study of Subsurface Environmental Processes [CESEP], Dep. of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401 currently at International Services and Projects Division, National Cooperative for the Disposal of Radioactive Waste, Wettingen 5430, Switzerland U.S. Army Corps of Engineers Research and Development Center, Vicksburg, MS 39180
Thermal conductivity and diffusivity were measured for different sands under varied water saturation and temperature. Data showed that the thermal properties increased noticeably for sample temperatures above 50°C. At sample temperatures between 30 and 50°C, changes in thermal properties were small.
Due to the dynamic nature of the shallow subsurface, knowledge of soil thermal properties across a wide range of soil moisture and temperature conditions is necessary to accurately describe heat transport in many settings. Soil thermal properties are difficult to measure at high temperatures, however, due to the lack of suitable measurement devices and the potential for measurement-induced changes. Therefore, thermal property data are often scarce and incomplete and very often limited to specific soils. Due to this scarcity of accurate experimental data, empirical relationships often do not accurately predict the thermal properties of soils as a function of both soil moisture and temperature. In this study, thermal conductivity and diffusivity were measured for silica sands under loose and tight packing conditions and a field sand under varied water saturation and temperature. Several recent sensor-based technologies were integrated into a small cell modified to have a network of sampling ports, continuously monitoring water saturation, temperature, and soil thermal properties. For the test sands studied, data showed that the thermal conductivity and diffusivity increased noticeably for sample temperatures >50°C. At sample temperatures between 30 and 50°C, any change in thermal properties with temperature was small. Thermal conductivities measured in this study were compared with independent estimates made using empirical models from the literature. In general, good agreement was observed for most thermal conductivity data when proper fitting parameters were established, except at intermediate saturation values.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2013. . Copyright © by the Soil Science Society of America, Inc.