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ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

STUDY OF HEAT TRANSFER IN EVACUATED INSULATIONS AT VARIOUS GAS LOADINGS

Get access (open in a dialog) DOI: 10.1615/IHTC8.400
pages 709-714

Abstract

Evacuated multilayer and mass insulations were evaluated for applications in an environment with relatively large amounts of residual gases. Experiments were conducted for two multilayer insulation specimens and one mass insulation specimen at a mean temperature of 205°C and at pressures ranging from 1.0 × 103 to 1.0 × 105 N/m2. The residual gases investigated included air and hydrogen. Models based on the temperature jump theory and existing fibrous insulation formulations were successfully used to study the contributions from gas conduction, solid conduction, and radiation. The characteristic dimension of an evacuated insulation significantly affects its performance in the presence of the residual gases. It was shown that a properly designed multilayer insulation could perform better than mass insulation at low pressures. The thermal accommodation coefficients between hydrogen and the multilayer insulation materials are lower than those between air and the materials.