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Thermal Conductivity Measurements of Cryogenic Insulations at High Pressures.
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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A special test apparatus was developed to measure apparent thermal conductivity of powder insulations at cryogenic temperatures and high interstitial gas pressures. The test apparatus consisted of two concentric cylinders, with the test insulation contained in the annulus between the two cylinders. Thermal conductivity measurements were based on the radial heat flow from the outer cylinder to the inner cylinder. Tests were conducted at pressures from 14.7 to 5000 psia and a nominal temperature difference of 200 to 520R. Four common loose-fill, powder-type insulations were tested vermiculite, diatomaceous earth, and two grades of perlite. Test results indicated that for all four insulations tested, apparent thermal conductivity was only weakly dependent on the interstitial gas pressure for pressures above 2000 psia. Modified author abstract
APPROVED FOR PUBLIC RELEASE