A Technique for Determining Thermal Transport Properties of Small, Electrically Conductive Liquid or Solid Specimens

Report No. ARL-TR-1905
Authors: McQuaid, Micahel; Cohen, Max
Date/Pages: March 1999; 47 pages
Abstract: The experimental approach developed by Miller and Kotlar for determining the thermal conductivity and thermal diffusivity of small, solid, energetic-material specimens-"Technique for Measuring the Thermal Diffusivity/ Conductivity of Small Thermal Insulator Specimens," Review of Scientific Instruments, vol. 64, pp. 2954-2960, 1993-has been modified and extended for use in determining these properties for electrically conductive materials, including liquids. As in the technique developed by Miller and Kotlar, these properties are determined from the transient temperature response of a point in an experimental system consisting of two "semi-infinite" media, a plane of which is subjected to a well-defined heat flux. However, to allow the technique to be employed with electrically conductive specimens, the experiment is configured so that the heat flux is generated at a plane in a nonconductive solid (as opposed to the interface between the media), and the temperature response is measured in this solid as well. The parameter (lambda pc(sub p))(sup 1/2) is obtained by fitting a numerical simulation of the heat transfer process to the temperature response. Coupling the model to a nonlinear least-squares fitting routine facilitates this effort. To obtain absolute values for the specimen's thermal conductivity and thermal diffusivity, knowledge of its density and heat capacity is required. The viability of the experimental approach was established through experiments with water, methanol, and ethylene glycol, and the technique was employed to obtain the thermal conductivity of liquid propellant XM46 for temperatures in the range 20-60 deg C.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 1999