Novel Thermal Conductivity Measurement Technique Utilizing a Transient Multilayer Analytical Model of a Line Heat Source Probe for Extreme Environments

Advancements in thermal properties analysis are crucial for continual improvement of existing and next generation reactors, space exploration, and environmental safety. Extreme environments pose a great hurdle for instrumentation to measure real time thermal properties due to the extreme temperatures, high radiation, and variable electromagnetic environments. Nevertheless, measurement systems are tremendously important for the design, performance, and safety considerations of nuclear fuels, spacecraft, and deep sea/deep earth drilling. Thermal properties may change significantly in these environments creating challenging problems for temperature and thermal conductivity measurement systems. A recent focus has surrounded improvements in such systems for accurate determination of temperature and thermal properties to increase efficiencies, reduce costs, calibrate models, and tackle problems previously unfulfilled. Here we report on the thermal quadrupoles method to develop analytical models, which have been verified using multiphysics finite element analysis, for thermal conductivity measurements conducted with a line heat source probe. A novel measurement technique was developed to monitor the temperature rise of the sample via the temperature dependent resistance of the probe’s heater wire. This innovative approach provides a feasible method for extracting thermal conductivity in extreme environments.