Characteristic evaluation of cooling technique using liquid nitrogen and metal porous media

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)

Abstract

A remountable high-temperature superconducting magnet, whose segments can be mounted and demounted repeatedly, has been proposed for construction and maintenance of superconducting magnet and inner reactor components of a fusion reactor. One of the issues in this design is that the performance of the magnet deteriorates by a local temperature rise due to Joule heating in jointing regions. In order to prevent local temperature rise, a cooling system using a cryogenic coolant and metal porous media was proposed and experimental studies have been carried out using liquid nitrogen. In this study, flow and heat transfer characteristics of cooling system using subcooled liquid nitrogen and bronze particle sintered porous media are evaluated through experiments in which the inlet degree of subcooling and flow rate of the liquid nitrogen. The flow characteristics without heat input were coincided with Ergun's equation expressing single-phase flow in porous materials. The obtained boiling curve was categorized into three conditions; convection region, nucleate boiling region and mixed region with nucleate and film boiling. Wall superheat did not increase drastically with porous media after departure from nucleate boiling point, which is different from a situation of usual boiling curve in a smooth tube. The fact is important characteristic to cooling superconducting magnet to avoid its quench. Heat transfer coefficient with bronze particle sintered porous media was at least twice larger than that without the porous media. It was also indicated qualitatively that departure from nucleate boiling point and heat transfer coefficient depends on degree of subcooling and mass flow rate. The quantitative evaluation of them and further discussion for the cooling system will be performed as future tasks.

Original languageEnglish
Title of host publicationAdvances in Cryogenic Engineering - Transactions of the Cryogenic Engineering Conference - CEC, Volume 59
EditorsSusan Breon, Jennifer Marquardt, Thomas Peterson, Michael DiPirro, John Pfotenhauer, Jonathan Demko, James Fesmire, Arkadiy Klebaner, Sidney Yuan, Al Zeller, Peter Kittel, Gregory Nellis, Mark Zagarola
PublisherAmerican Institute of Physics Inc.
Pages597-604
Number of pages8
ISBN (Electronic)9780735412019
DOIs
Publication statusPublished - 2014
Event2013 Joint Cryogenic Engineering and International Cryogenic Materials Conferences, CEC/ICMC 2013 - Anchorage, United States
Duration: 2013 Jun 172013 Jun 21

Publication series

NameAIP Conference Proceedings
Volume1573
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference2013 Joint Cryogenic Engineering and International Cryogenic Materials Conferences, CEC/ICMC 2013
Country/TerritoryUnited States
CityAnchorage
Period13/6/1713/6/21

Keywords

  • Heat transfer
  • Liquid nitrogen
  • Porous media

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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