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Tuesday, May 5, 2020 | History

3 edition of Design and application of gas-gap heat switches found in the catalog.

Design and application of gas-gap heat switches

Design and application of gas-gap heat switches

final report for phase II

  • 213 Want to read
  • 8 Currently reading

Published by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC, Springfield, Va .
Written in English

    Subjects:
  • Coolers.,
  • Cryogenics.,
  • Electrical resistivity.,
  • Refrigerators.,
  • Switches.,
  • Thermal conductivity.

  • Edition Notes

    Other titlesDesign and application of gas gap heat switches.
    StatementC.K. Chan, R.G. Ross, Jr.
    SeriesNASA contractor report -- NASA CR-187339.
    ContributionsRoss, R. G. 1942-, United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL18077380M

    This banner text can have markup.. web; books; video; audio; software; images; Toggle navigation. contents paqe volume i contents viii volume iii contents ix volume iv contents xvi section a - fundamentals collection efficiency of electrostatic precipitators by numerical simulation 1 e.a. samuel the effects of corona electrode geometry on the operational characteristics of an esp 31 g. rinard, d. rugg, w. patten and l.e. sparks theoretical methods for predicting electrical conditions.

    You can write a book review and share your experiences. Other readers will always be interested in your opinion of the books you've read. Whether you've loved the book or not, if you give your honest and detailed thoughts then people will find new books that are right for them. A Preliminary Conceptual Design Report (Pre-CDR) [4, 5] was published in March This document is the second volume of the Conceptual Design Report (CDR). The first volume [6], released in July , describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios.

    At the time that, at Labofex, we were making the first inroads into this problem in the wake of our X-ray studies, an interest in this region was also kindled by the search for high-power switches that might replace flash-over switches (triggered gas gap breakdown switches), rotating .   Waste heat is removed from the cold end of the power convertor at temperatures ranging from °C, depending on the application, using conductive coupling to radiator panels. The NASA projects target power systems able to produce a range of electrical power output levels based on the available form factors of space rated fuel sources.


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Design and application of gas-gap heat switches Download PDF EPUB FB2

Design and Application of Gas-Gap Heat Switches Final Report of Phase II C. Chan R. Ross, Jr. (NASA-CR) DESTGN ANO APPLTCATTQN OF GAS-GAP HEAT SWTTCHES Fin_l Report (JPL) 62 p CcCL 09C N uncles G 0BI Ma Prepared for Air Force Space Technology Center Kirtland Air Force Base Under the Sponsorship of theFile Size: 2MB.

Get this from a library. Design and application of gas-gap heat switches: final report for phase II. [C K Chan; R G Ross; United States. National Aeronautics and Space Administration.]. Helium liquid-gap and gas-gap heat switches are operated at 2 K.

They are tested for their on- and off-conductance and turn-on and turn-off times. The measured on- and off-conductance of the heat switches are close to the theoretical by: 3. Thermal control at 1 K is still demanding for heat switches development.A gas gap heat switch using 3He gas as the heat-transfer fluid was tested and characterized.

A gas gap heat switch reaches its high conductance state when the gap between two exchange surfaces is filled with a conducting gas. The broader the surface and the narrower the gap the higher the. –Typical “Low-temperature” switches use titanium (superconduct below ~ K) –Higher temperature switches may use stainless steel Source: Shirron, Canavan, DiPirro et al., Passive gas-gap heat switches for use in adiabatic demagnetization refrigerators AIP Conference Proceedings().

Concluding remarks The version V0 of this type of dilatation switch showed that a gas-gap heat switch with reasonable performances can be built very simply and the ON conductance state can be compared with other types of gas-gap heat switches [].Cited by: 2. The thermal switch can operate from cryogenic to very high temperatures well above ºC.

In addition, since the gas gap can be evacuated, a vacuum formed between the surfaces can yield a near % shunt of the conductive thermal path.

Our calculations show that an “On/Off Heat Flow Ratio” value of can be surpassed by this design. The requirements for these heat switches are discussed and related to important compressor parameters.

It is shown that under certain conditions a sorption compressor can be operated without heat switches at all. Furthermore, the static heat transfer behaviour of a gas gap is modelled in detail and compared with experiments on a μm gas by: Abstract—Heat switches are important devices in many cryogenic setups, especially in space applications and many systems have been used to allow a good ability to make or break a thermal contact.

Among them, the so-called gas gap heat switches are known to be very reliable and simple due to the nonexistence of moving parts. In this paper we proposed an innovative design for a gas gap heat switch that leverages on the differential thermal expansion of the materials that compose the switch to create a very narrow gap.

Below ≈70 K, a gap as small as 8 μm would be obtained, based on the assumption that the whole device would be isothermal at the melting temperature Cited by: 8.

The so‐called gas gap heat switch, in which the pressure is managed by a coupled small cryopump having no moving parts, is known to be a very reliable and simple heat ical design improvements can lead to optimized ON or OFF characteristics of a gas‐gap heat switch.

Their ON conductance characteristics are mainly determined by the gas properties and the gap by: 7. We have designed, built, and tested a gas-gap heat switch that turns on and off passively, without the need for a separate, thermally activated getter.

This switch uses 3He condensed as a thin film on alternating plates of copper. The switch is thermally conductive at temperatures above about K, and is insulating if either end of the switch cools below about by: Hydrogen and Neon Gas-Gap Heat Switch I.

Catarino 1, L. Duband2, G. Bonfait 1 CEFITEC – Departamento de Física FCT/UNL, P Caparica, Portugal 2 Service des Basses Temperatures, CEA/INAC, Grenoble Cedex 9, France ABSTRACT Heat switches are important devices in many cryogenic setups, especially in space applications.

This passive gas‐gap heat switch for adiabatic demagnetization refrigerator has adsorption unit within containment tube which continuously varies on/off temperature of heat switch over range of temperatures.

First and second sets of fins are connected with first and second copper conductors respectively. Inorganics, an international, peer-reviewed Open Access journal. The statements, opinions and data contained in the journal Inorganics are solely those of the individual authors and contributors and not of the publisher and the editor(s).

@article{osti_, title = {Parylene-based active micro space radiator with thermal contact switch}, author = {Ueno, Ai and Suzuki, Yuji}, abstractNote = {Thermal management is crucial for highly functional spacecrafts exposed to large fluctuations of internal heat dissipation and/or thermal boundary conditions.

Since thermal radiation is the only means for heat removal, effective control. The microstructure of an annealed alloy with a Zr8Ni21 composition was studied by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The presence of three phases, Zr8Ni21, Zr2Ni7, and Zr7Ni10, was confirmed by SEM/X-ray energy dispersive spectroscopy compositional mapping and TEM electron diffraction.

Distribution of the phases and their morphology Cited by: 2. Search the leading research in optics and photonics applied research from SPIE journals, conference proceedings and presentations, and eBooks.

Of these, papers are published here, in Volume 39 of Advances in Cryogenic Engineering. Once again the volume is published in two books.

This volume includes a cumulative index for the CEC volumes from (volu23,25,27,29,31,33,35,37, and 39 of Advances in Cryogenic Engineering).

The first 20 volumes are indexed in Volume. "This book provides a comprehensive description of the theory and practice of closed-cycle sorption coolers, cryogenic devices used to cool samples to very low temperatures from 4K to 30 mK and below.

A comprehensive list of MATLAB routines used in the simulation and design of the various systems is provided at the end of the book.be overcome in order to realize the design concept.

As stated in a grant proposal: Success basically hinges on developing heat switches that can conduct heat very well in the on state at low temperature, yet provide good isolation in the off state. Several switches are needed to span the temperature range from mK up to 10 K.

[D2]. Posted 2/25/10 PM, messages.