Techniques for Reducing Radiation Heat Transfer between 77 and 4.2 K

Leung, E.; Fast, R. W.; Hart, H. L.; Heim, J.R.

doi:10.1007/978-1-4613-9856-1_59

Cited by 33 publications

(5 citation statements)

References 9 publications

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“…The heatmeter has distinct advantages over the gas metering method in that: (1) the data acquisition time is greatly reduced, since reservoir equilibrium is no longer necessary (as with the ga!Mete~)--only t~~t sample steady-state ls required; (2) the heatmeter is independent of any heat transfer between the helium reservoir and the test vessel; and (3) the resolution of the heatmeter is in micro-watts versus milli-watts for the gasmeter.…”

Section: Heat Leak Measurement Methodsmentioning

confidence: 99%

Heat leak measurements facility

Gonczy¹,

Kuchnir²,

Nicol³

et al. 1985

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Heat leak measurements of superconducting magnet suspension systems, and multilayer insulation (MLI) systems are important for the optimum design of magnet cryostats. For this purpose, a cryogenic test facility was developed having a versatile functional end in which test components of differing geometrical configurations can be installed and evaluated. This paper details the test facility design and operating parameters. Experimental results of heat leak measurements to 4.5 K obtained on a post type support system having heat intercepts at 10 K and 80 K are presented. Included are measurements obtained while operating the 10 K intercept at temperatures above 10 K, i.e., in the 10-40 K range. Also reported is a description of the test facility conversion for a heat load study of several MLI systems with variations of MLI installation technique. The results of the first MLI system tested are presented.

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Section: Heat Leak Measurement Methodsmentioning

confidence: 99%

Heat leak measurements facility

Gonczy¹,

Kuchnir²,

Nicol³

et al. 1985

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“…Convective heat transfer is effectively eliminated via vacuum. The radiation load for 40 m of cryostat is estimated to be < 0.1 W. This estimate is based on measurements of radiation heat exchange between surfaces at 77 K and 4.2 K [3]. Approximately 0.031 W of the radiation load is due to heat transfer through five layers of MLI and a single layer of 3M #425 Al tape mounted to the surface of the cold stage.…”

Section: Cryostatmentioning

confidence: 99%

Design of a cryogenic system for a 20m direct current superconducting MgB2 and YBCO power cable

Cheadle

Bromberg

Jiang

et al. 2014

AIP Conference Proceedings

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Abstract. The Massachusetts Institute of Technology, the University of Cambridge in the United Kingdom, and Tsinghua University in Beijing, China, are collaborating to design, construct, and test a 20 m, direct current, superconducting MgB2 and YBCO power cable. The cable will be installed in the State Key Laboratory of Power Systems at Tsinghua University in Beijing beginning in 2013. In a previous paper [1], the cryogenic system was briefly discussed, focusing on the cryogenic issues for the superconducting cable. The current paper provides a detailed discussion of the design, construction, and assembly of the cryogenic system and its components. The two-stage system operates at nominally 80 K and 20 K with the primary cryogen being helium gas. The secondary cryogen, liquid nitrogen, is used to cool the warm stage of binary current leads. The helium gas provides cooling to both warm and cold stages of the rigid cryostat housing the MgB 2 and YBCO conductors, as well as the terminations of the superconductors at the end of the current leads. A single cryofan drives the helium gas in both stages, which are thermally isolated with a high effectiveness recuperator. Refrigeration for the helium circuit is provided by a Sumitomo RDK415 cryocooler. This paper focuses on the design, construction, and assembly of the cryostat, the recuperator, and the current leads with associated superconducting cable terminations.

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“…The heat flux of radiation-dominated MLI was calculated through the iterative calculation of Equations (7) and (8) for a set of initial trial values of the radiation heat flux and boundary temperature. The effective emittance and heat transfer coefficient were estimated from the calculated results of heat flux of the radiation-dominated MLI, as shown in Figures 9 and 10.…”

Section: Confirmation Of Temperature Dependence Of MLI Thermal Permentioning

confidence: 99%