THERMOPHYSICAL PROPERTIES AT HIGH TEMPERATURES MEASURED BY DIRECT HEATING METHODS.
Technical rept., 1 Jul 69-31 Oct 70,
THERMOPHYSICAL AND ELECTRONIC PROPERTIES INFORMATION ANALYSIS CENTER LAFAYETT E IN
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An analysis of direct heating methods, in which the sample is heated by passing an electric current through it, is presented. These methods are used for measuring thermophysical properties at high temperatures. It was demonstrated that mathematical approximations severly limit the applicability and accuracy of the techniques described in the literature. However, new techniques developed under the present program do not employ severe mathematical approximations and correctly include temperature-dependent properties. Thus the new techniques are significantly more accurate and orders of magnitude more flexible than the previous techniques. Data on the thermal conductivity, electrical resistivity, hemispherical total emittance, spectral normal emittance 0.65 microns and Wiedemann-Franz-Lorenz ratio for two samples of Ta - 10W alloy to 2600 K are presented. Accuracies are believed to be within plus or minus 1 for the electrical resistivity, plus or minus 2 for the emittance and plus or minus 4 for thermal conductivity. Progress on the development of an apparatus to measure the thermal conductivity of carbongraphite fiber is described. Author
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