Development of a test apparatus to determine thermal properties of rock specimens

Abstract

Understanding thermal properties is necessary for the development of both shallow and deep geothermal systems. Thermal properties can also be used for understanding the development and assessing weathering in a variety of materials. An experimental apparatus has been developed to determine the thermal properties of rock samples. The apparatus consists of a ring heater, aluminum adaptor, and a stainless steel base. Three thermocouples are used to measure heat flow through the base. The rock specimen sits on top of the stainless steel base. Twelve thermocouples, arranged vertically in sets of three at the cardinal positions around the rock sample, are used to measure heat flow through the sample. The apparatus is wrapped in insulation to prevent heat loss. The top of the apparatus is open so a thermal camera can capture the temperature increase at the top of the specimen. Thermal analyses conducted using finite element modeling have verified the design of the apparatus. Two limestone specimens have been tested and experimentally derived thermal conductivities are within experimental ranges of thermal conductivities presented in the literature