The Thermal Conductivity of the Rocks in the Bureau of Mines Standard Rock Suite
The thermal conductivities of eight rocks in the Bureau of Mines Standard Rock Suite were measured in air over the range 373 to 533 K. The rocks and their average thermal conductivities at 373 K before thermal cycling were (1) Sioux quartzite, 5.5 W/(m·K); (2) St. Cloud gray granodiorite, 2.7 W/(m·K); (3) Dresser basalt, 3.0 W/(m·K); (4) Barre granite, 2.5 W/(m·K); (5) Holston limestone, 2.5 W/(m·K); (6) Westerly granite, 2.3 W/(m·K); (7) Berea sandstone, 2.2 W/(m·K); and (8) Salem limestone, 1.7 W/(m·K). The thermal conductivity at a given temperature decreased by as much as 9% after initial heating to maximum temperature (533 K), but additional heating cycles had no further effect. Variations due to orientation (anisotropy) were within the precision of measurements (±5%). The thermal conductivities were linear with the reciprocal of the temperature and were within 14% of published data by other methods.
Measurements were made by the cut-bar comparison method using Pyroceram 9606 glass-ceramic metering bars. The apparatus was a Dynatech TCFCM-N20 comparative instrument controlled by a Hewlett Packard 3052A data acquisition system. The computer control increased the instrument efficiency by more than a factor of 3 because overnight and weekend operation could be continued without surveillance and because computations were automatic.
KeywordsThermal Conductivity Thermal Conductivity Measurement Salt Dome Berea Sandstone Westerly Granite
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