Transient Heat Transfer in a Channel of Liquid or Supercritical Helium

  • D. L. Kingsbury
  • X. Huang
  • S. W. Van Sciver
Chapter
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 39)

Abstract

Two thin-film sensors were used to measure temperatures on opposing (horizontal) surfaces of a rectangular channel, 1.3 cm long, with channel heights of 0.2, 0.94, and 2.54 mm and at pressures of 1, 2, and 3 bar. Power densities exceeding 4 W/cm2 could be obtained in 160 ms pulses without burning out the heater sensor, producing temperature changes as high as 40 K on the active surface and 13 K on the passive surface. This paper reports results for heat fluxes up to 2 W/cm2. Data at 1 bar show the abrupt temperature “takeoff” on the heater surface associated with the transition from nucleate to film boiling; takeoff times exhibit a Q-2 behavior, varying only slightly with gap width, consistent with Schmidt’sl,2 diffusion-vaporization model. At the shorter gap widths temperatures are shifted higher, the height of the takeoff rise changes, the steady state nucleate boiling maximum heat flux decreases, and transition time to steady state behavior is greatly increased. Under 2 and 3 bar conditions the temperature rises more smoothly, and is lower at 3 bar. On the passive surface the effects of different gap widths and pressures are quite pronounced. Response is negligible for a 2.54 mm gap. Temperature rise times in a 0.2 mm gap mostly fall in a 15–30 ms range, relatively independent of heat flux. At early times the 2 bar response climbs slowly, but above a threshold in the 1.0–1.5 W/cm2 range it exhibits an abrupt transition and overtakes the more gradual 3 bar response.

Keywords

Helium Epoxy Boiling Delrin 

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References

  1. 1.
    C. Schmidt, Review of steady-state and transient heat transfer in pool boiling helium I, IIR Commission A 1/2 6: 17, Saclay, France (1981).Google Scholar
  2. 2.
    C. Schmidt, Transient heat transfer into a closed small volume of liquid or supercritical helium, Cryogenics 28: 585 (1988).CrossRefGoogle Scholar
  3. 3.
    W. G. Steward, Transient helium heat transfer Phase I—static coolant, Int. J. Heat Mass Transfer 21: 863 (1978).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • D. L. Kingsbury
    • 1
  • X. Huang
    • 1
  • S. W. Van Sciver
    • 1
  1. 1.National High Magnetic Field LaboratoryTallahasseeUSA

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