Experimental Determination of Thermal Accommodation Coefficients of Rarefied Argon, Helium, Nitrogen, and Water Vapor on Stainless Steel Concentric Cylinders
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Authors
Lane, Mitchell G
Issue Date
2020
Type
Thesis
Language
Keywords
Heat Transfer , Rarefied Gas , Temperature Jump Coefficient , Thermal Accommodation Coefficient
Alternative Title
Abstract
During vacuum drying of used nuclear fuel canisters, the temperature of the assemblies may considerably increase due to the effect of gas rarefaction at low pressure, and the lack of buoyancy induced gas motion. The effect of rarefaction can manifest as a temperature jump thermal resistance at the gas-solid interfaces that causes the fuel temperature to increase compared to non-rarefied conditions (no-temperature jump). It is important to maintain the temperature of the assemblies below certain limits to ensure the integrity and retrievability of the used nuclear fuel and internal components of the canister. Therefore, it is crucial to accurately determine the effect of gas rarefaction on the fuel temperature during vacuum drying process.The objective of this thesis is to experimentally and numerically study the effect of gas rarefication on heat transfer across a 2 mm annular gap filled with different gases (argon, helium, nitrogen, and water vapor) at different pressures. The results from the experiments are used to determine the temperature jump and thermal accommodation coefficients for these gases on a stainless steel surface. The thermal accommodation coefficients were determined to be 0.35-0.38 for helium, 0.95-0.97 for argon, 0.88 for nitrogen, and 1.01 for water vapor. These determinations compare well with literature sources and provide a first determination of temperature jump and thermal accommodation coefficient of water vapor on a stainless steel surface. These results will be then used to predict the temperature of the fuel assemblies during vacuum drying and will be used to make rough determinations of temperature jump and thermal accommodation coefficients of gas mixtures.