Thermodynamic optimization of thermal radiation shields for a cryogenic apparatus

Eyssa, Y.M.; Okasha, O.

doi:10.1016/0011-2275(78)90070-x

Cited by 18 publications

(4 citation statements)

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“…Because the suppression is observable at cryogenic temperatures, this phenomenon could be exploited to reduce heat loss through radiative transfer in cryogenic devices. However, a simpler technique of reducing radiative transfer is to use radiation shields [20].…”

Section: -10mentioning

confidence: 99%

Minimum radiative heat transfer between two metallic half-spaces due to propagating waves

Narayanaswamy

Mayo²

2016

Journal of Quantitative Spectroscopy and Radiative Transfer

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The gap dependence of radiative energy transfer due to propagating waves between two identical metallic half-spaces separated by vacuum is investigated. The dielectric function of the metallic half-spaces is described by the Drude model. Analytical expressions for the minimum radiative heat transfer coefficient, h min , and the gap, d min , at which the minimum value of radiative transfer is attained are determined in terms of the parameters of the dielectric function and the absolute temperature T. We show that h min ∝ T 2 in the high temperature limit and h min ∝ T 7/2 in the low temperature limit.

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Section: -10mentioning

confidence: 99%

Minimum radiative heat transfer between two metallic half-spaces due to propagating waves

Narayanaswamy

Mayo²

2016

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…21,22 The flight cryostat has MLI installed in such a way that reduces compression, which would otherwise increase conduction through the insulation, and enables proper evacuation of interstitial gas. 18,19,23 However, thermal conduction is inevitable when adjacent layers are in sporadic contact. In the absence of a leak, the pressure inside the VV remains roughly constant after equilibrium has been reached.…”

Section: Conductionmentioning

confidence: 99%

“…This is roughly a factor of two lower than the quoted optimal packaging density for MLI. 18,19 However, lower packaging densities enable successful evacuation of the vacuum vessel.…”

Section: Radiation Shields Heat Exchangers and Multi-layer Insulationmentioning

confidence: 99%

Thermal architecture for the SPIDER flight cryostat

et al. 2010

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We describe the cryogenic system for spider, a balloon-borne microwave polarimeter that will map 8% of the sky with degree-scale angular resolution. The system consists of a 1284 L liquid helium cryostat and a 16 L capillary-filled superfluid helium tank, which provide base operating temperatures of 4 K and 1.5 K, respectively. Closed-cycle 3 He adsorption refrigerators supply sub-Kelvin cooling power to multiple focal planes, which are housed in monochromatic telescope inserts. The main helium tank is suspended inside the vacuum vessel with thermally insulating fiberglass flexures, and shielded from thermal radiation by a combination of two vapor cooled shields and multi-layer insulation. This system allows for an extremely low instrumental background and a hold time in excess of 25 days. The total mass of the cryogenic system, including cryogens, is approximately 1000 kg. This enables conventional long duration balloon flights. We will discuss the design, thermal analysis, and qualification of the cryogenic system.

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“…These latter shield temperatures and number of insulation layers appear to yield loads consistent with other optimized designs. [25,26,27] Heat is transmitted via radiation, conduction, and convection from heat shield to MLI to heat shield to magnet. Heat leaks into the magnet through MLI and heat shields are estimated using the standard method [28,29] given by ~M L I (TH -Tc)?…”

Section: Heat Leaksmentioning

confidence: 99%

Applications of Superconductivity to Very Shallow Water Mine Sweeping

Golda

Walters

Green

1992

Naval Engineers Journal

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Recent experiences in the Persian Gulf have clearly demonstrated the need for improved mine sweeping, or mine counter‐measures (MCM), to support amphibious operations. Characteristics of MCM systems currently used to counter magnetic influence mines restrict sweep rates, limit the ability to accurately simulate a ship's magnetic signature, and require a minimum water depth. Advances in superconducting technology over the last twenty years have significantly increased the feasibility of superconducting mine countermeasures (SCMCM) for magnetic influence mines. An SCMCM system would be small, light, and simple compared to currently deployed MCM systems. Superconducting magnets could be fabricated in steady state configurations or configurations that would significantly improve the ability to simulate non‐symmetric, time‐varying magnetic signatures of ships. SCMCM systems could be deployed from either surface or airborne platforms. An airborne system would protect the magnet from blast damage, permit the highest sweep rates, and allow unrestricted sweeping over entire amphibious objective areas, including the surf. A light weight SCMCM system would permit use of additional airborne platforms which may include remotely piloted airborne vehicles. Remotely piloted surface or airborne vehicles would totally eliminate risks to personnel. An SCMCM system could be demonstrated immediately utilizing existing technology and may offer significant advantages over existing MCM systems used to counter magnetic influence mines in very shallow water.

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Thermodynamic optimization of thermal radiation shields for a cryogenic apparatus

Cited by 18 publications

References 0 publications

Minimum radiative heat transfer between two metallic half-spaces due to propagating waves

Minimum radiative heat transfer between two metallic half-spaces due to propagating waves

Thermal architecture for the SPIDER flight cryostat

Applications of Superconductivity to Very Shallow Water Mine Sweeping

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