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Multiphase Science and Technology
SJR: 0.124 SNIP: 0.222 CiteScore™: 0.26

ISSN Imprimir: 0276-1459
ISSN On-line: 1943-6181

Multiphase Science and Technology

DOI: 10.1615/MultScienTechn.v12.i3-4.80
16 pages

LOCAL FLOW BOILING HEAT TRANSFER COEFFICIENTS IN NARROW CONDUITS

J. R. Baird
Department of Chemical Engineering, University of Sydney
Z. Y. Bao
Department of Chemical Engineering, University of Sydney
David F. Fletcher
School of Chemical and Biomolecular Engineering, The University of Sydney, Australia
Brian S. Haynes
School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia

RESUMO

This paper presents local saturated and subcooled boiling heat transfer coefficients for flow in narrow conduits. Flow of Freon R11, HCFC123 and CO2 in circular pipes with diameters of 0.92 and 1.95 mm over a wide range of heat fluxes, mass fluxes, qualities and system pressures is examined. In all cases the saturated boiling heat transfer coefficient is found to be a function of the wall heat flux and not of the mass flux or quality, indicating the dominant heat transfer mechanism is nucleate boiling. The saturated data are fitted well by the nucleate pool boiling correlation of Cooper. The subcooled data suggest that heat transfer is also controlled by nucleation phenomena and a model based on the mixing of subcooled fluid into the superheated layer adjacent to the wall is proposed.