Nuclear Engineering and Technology

  • 제38권2호
  • /
  • Pages.139-146
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  • 2006
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  • 1738-5733(pISSN)
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  • 2234-358X(eISSN)
한국원자력학회 (Korean Nuclear Society)
권호 표지

CRITICAL HEAT FLUX FOR DOWNWARD-FACING BOILING ON A COATED HEMISPHERICAL VESSEL SURROUNDED BY AN INSULATION STRUCTURE

  • Yang, J. (Department of Mechanical & Nuclear Engineering Pennsylvania State University) ;
  • Cheung, F.B. (Department of Mechanical & Nuclear Engineering Pennsylvania State University) ;
  • Rempe, J.L. (Idaho National Engineering and Environmental Laboratory) ;
  • Suh, K.Y. (Department of Nuclear Engineering, Seoul National University) ;
  • Kim, S.B. (Korea Atomic Energy Research Institute)
  • 발행 : 2006.02.01
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초록

An experimental study was performed to evaluate the effects of surface coating and an enhanced insulation structure on the downward facing boiling process and the critical heat flux on the outer surface of a hemispherical vessel. Steady-state boiling tests were conducted in the Subscale Boundary Layer Boiling (SBLB) facility using an enhanced vessel/insulation design for the cases with and without vessel coatings. Based on the boiling data, CHF correlations were obtained for both plain and coated vessels. It was found that the nucleate boiling rates and the local CHF limits for the case with micro-porous layer coating were consistently higher than those values for a plain vessel at the same angular location. The enhancement in the local CHF limits and nucleate boiling rates was mainly due to the micro-porous layer coating that increased the local liquid supply rate toward the vaporization sites on the vessel surface. For the case with thermal insulation, the local CHF limit tended to increase from the bottom center at first, then decrease toward the minimum gap location, and finally increase toward the equator. This non-monotonic behavior, which differed significantly from the case without thermal insulation, was evidently due to the local variation of the two-phase motions in the annular channel between the test vessel and the insulation structure.

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참고문헌

  1. Cheung, F.B., Haddad, K. and Liu, Y.C., Critical Heat Flux (CHF) Phenomena on a Downward Facing Curved Surface, NUREG/CR-6507, U.S. Nuclear Regulatory Commission, Washington, D.C., June 1997
  2. Cheung, F. B. and Liu, Y. C., Critical Heat Flux (CHF) Phenomenon on a Downward Facing Curved Surface:Effects of Thermal Insulation, NUREG/CR-5534, U.S. Nuclear Regulatory Commission, Washington, D.C., September 1998
  3. Cheung, F. B., Yang, J. and Dizon, M. B., On the Enhancement of External Reactor Vessel Cooling of High-Power Reactors, The 10th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Paper G00403, 2003
  4. Cheung, F. B., Yang, J. and Dizon, M. B., Scaling of downward facing boiling and steam venting in a reactor vessel/insulation system, Proceedings of HT2003, ASME summer heat transfer conference, Paper HT2003-40208, 2003
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