Progress in Superconductivity and Cryogenics (한국초전도ㆍ저온공학회논문지)

The Korean Society of Superconductivity and Cryogenics (한국초전도저온학회)
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Thermal diffusion experiment of impulsive heat in subcooled liquid nitrogen

과냉 액체질소 내에서 순간적 열확산 실험

  • 최진혁 (홍익대학교 기계시스템디자인공학과) ;
  • 하찬준 (홍익대학교 기계시스템디자인공학과) ;
  • 변정주 (홍익대학교 과학기술연구소) ;
  • 장호명 (홍익대학교 기계시스템디자인공학과) ;
  • 김호민 (LS산전 전력연구소) ;
  • 고태국 (연세대학교 전기전자공학부)
  • Published : 2006.03.01
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Abstract

Transient heat transfer caused by an impulsive heating in subcooled liquid nitrogen is investigated experimentally. This study is part of out ongoing efforts directed to a stable cryogenic cooling system lot superconducting fault current limiters (SFCL). A thin heater attached by epoxy on one surface of a GFRP plate is immersed in liquid-nitrogen bath at temperatures between 77 K and 55 K. A strong heat flux up to $150W/cm^2$ is generated lot 100 ms, and the temperature of the heater sulfate is measured as a function of time. The behavior of bubbles on the heating surface can be explained by comparing the measured temperature history for vertical and two horizontal (up and down) orientations. It is concluded that the subcooling of liquid nitrogen below 70 K is very effective in suppressing bubbles, resulting in better thermal protection and faster recovery from an impulsive heat.

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References

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