Abstract
The effects of cracks in a multilayer insulation blanket on the heat load from 77 K to 4.2 K is a serious problem, but less so than from room temperature to 77 K. The technique of patching the cracks and the enhanced black cavity model developed to reduce heat flux through cracks in a MLI blanket to a 77 K surface were applied to the 77–4.2 K situation. The optimized patch covering technique is also very effective in this temperature region. The heat load through cracks in a MLI system between 77 K and 4.2 K, calculated by means of the enhanced black cavity model, is in agreement with the experimental data.
The temperature distributions were measured, and the corresponding equivalent thermal conductivity of the cracks were deduced. Both of these quantities were quite different from those measured at higher temperatures.
Work sponsored by the Universities Research Association, under contract with the U.S. Department of Energy.
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References
Q.S. Shu, R.W. Fast, and H.L. Hart, Theory and technique of reducing the effect of cracks in multilayer insulation from room temperature to 77 K, in: “Advances in Cryogenic Engineering,” Vol. 33, Plenum Press, New York.
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Q.S. Shu, Systematic study to reduce the effects of cracks in multilayer insulation. Part 1: theoretical model, Cryogenics 27: 249 (1987).
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© 1988 Springer Science+Business Media New York
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Shu, Q.S., Fast, R.W., Hart, H.L. (1988). Crack Covering Patch Technique to Reduce the Heat Flux From 77 k to 4.2 k Through Multilayer Insulation. In: Fast, R.W. (eds) Advances in Cryogenic Engineering. A Cryogenic Engineering Conference Publication, vol 33. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-9874-5_37
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DOI: https://doi.org/10.1007/978-1-4613-9874-5_37
Publisher Name: Springer, Boston, MA
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