Mechanism for extreme heat transfer conditions in water-cooling of fusion reactor components

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:196973

Lekakh, B M; Meyer, J E; Kazimi, M S ^[1]

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1. Massachusettes of Inst. of Technology, Cambridge, MA (United States)

Existing conceptual designs of some water-cooled fusion reactor components employ operating heat fluxes on the order of 15 MW/m{sup 2}, coolant velocities above 5 m/s, and pressures below 5 MPA. These conditions are quite different from most of those used to obtain existing correlations for subcooled nucleate boiling and critical heat flux. In addition, some available data in the range of interest shows that extrapolations of the correlations cannot be used. This paper deals with heat transfer mechanisms that must be incorporated in developing correlations for fusion reactor high heat flux components. Subcooled boiling is treated for smooth and finned heat transfer passages and for flows that are either straight or swirl. Two mechanism must be incorporated: suppression of nucleate boiling and critical heat flux caused by homogeneous nucleation. It is found out that for low pressures (<5 MPA) the subcooled nucleate boiling curves of smooth- and swirl-flows merge and show nucleation suppression (wall temperatures well above saturation without boiling occurrences). The suppression of nucleate boiling is observed for values of water pressure greater than 1 MPA for smooth, high velocity flows (water velocity >5 m/s). It is postulated that in these cases steam bubbles are destroyed by turbulent vortices.

• OSTI ID: 196973
• Report Number(s): CONF-940664--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COOLING SYSTEMS
CRITICAL HEAT FLUX
DIVERTORS
NUCLEATE BOILING
SUBCOOLED BOILING
THERMONUCLEAR REACTORS
VORTEX FLOW
WATER