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Apparent Thermal Conductivity Measurements by an Unguarded Technique

  • R. S. Graves
  • D. W. Yarbrough
  • D. L. McElroy

Abstract

An unguarded longitudinal heat flow apparatus for measuring the apparent thermal conductivity (λa) of insulations was tested with mean specimen temperatures from 300 to 330°K on samples up to 0.91 m wide, 1.52 m long, and 0.15 m thick. Heat flow is provided by a horizontal electrically heated Nichrome screen that is sandwiched between test samples that are bounded by temperature controlled copper plates and 9 cm of mineral fiber insulation. A determinate error analysis shows λa measurement uncertainty to be less than ±1.7% for insulating materials as thin as 3 cm. Three-dimensional thermal modeling indicates negligible error in λa due to edge loss for insulations up to 7.62 cm thick when the temperature difference across the sample is measured at the screen center. System repeatability and reproducibility were determined to be ±0.2%.

Keywords

Heat Flow Copper Plate Apparent Thermal Conductivity ASTM Special Technical Publication Density Thickness 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Purdue Research Foundation 1985

Authors and Affiliations

  • R. S. Graves
    • 1
  • D. W. Yarbrough
    • 1
  • D. L. McElroy
    • 1
  1. 1.Martin Marietta Energy Systems, Inc. Metals and Ceramics DivisionOak Ridge National LaboratoryOak RidgeUSA

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