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Impact of contamination of a metallic surface on its thermal absorptivity.

Number: 142

Author(s) : FROLEC J., KRALIK T., KRUTIL V.

Summary

Very low absorptivity values of metallic surfaces, which are often used in cryogenic systems, help to reduce the heat load transferred by thermal radiation on their cold parts. Low absorptivity may be, however, enhanced by an undesirable contaminant. Using dedicated apparatus in our laboratory, we measured total hemispherical absorptivity of a thin layer of ice, a mineral oil used in vacuum pumps, two different vacuum greases and a powdery basanite material, each applied individually in comparable amounts (approx. 0.23 mg.cm-2) on an aluminium surface. The contaminated surface was then exposed to thermal radiation emitted by a source at temperatures ranging from 20 K up to 280 K. Compared to the bare aluminium surface, we observed a significant increase of the original absorptivity after the contamination process and in the case of the powdery material also a nonlinear response to increasing irradiation. Our findings may have practical relevance for the design and thermal management of spacecrafts as well as ground-based cryogenic systems.

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Pages: 6 p.

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Details

  • Original title: Impact of contamination of a metallic surface on its thermal absorptivity.
  • Record ID : 30031061
  • Languages: English
  • Subject: Technology
  • Source: Proceedings of the 17th IIR International Conference on Cryogenics, Dresden, Germany, april 25-28 2023
  • Publication date: 2023/04/25
  • DOI: http://dx.doi.org/10.18462/iir.cryo.2023.0142

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