Determination of Thermal and Electrical Conductivity, Emittance and Thomson Coefficient at High Temperatures by Direct Heating Methods
Abstract
Progress on a program for evaluating direct electrical heating methods for high temperature thermal conductivity determinations is presented. Recent modifications, which increased the temperature capabilities of the apparatus, protected the samples from contamination and improved the accuracy and simplicity of the measurements, are described. A method for calculating the thermal conductivity using any three temperature versus position data points (3-point method) of a temperature profile was devised. Using this 3-point method, hundreds of conductivity values can be calculated per temperature profile. Computational schemes which utilize multiple data points or the output of the 3-point program are being developed. Substantial improvement in the accuracy and reproducibility of the computed thermal conductivity values has been obtained using these schemes. In addition, values for the Thomson coefficient are derived. Data on thermal conductivity, total hemispherical emittance, spectral emittance (0.65 microns), electrical resistivity, and Thomson coefficients for tantalum, ATJS graphite and tungsten to about 2700 K are presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1969
- Accession Number
- AD0697761
Entities
People
- Frederick E. Davis
- Raymond E. Taylor
- Reginald W. Powell
- Wilbur D. Kimbrough