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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

POOL BOILING FROM ENHANCED SURFACES IN PURE AND BINARY MIXTURES OF R-113 AND R-11

Get access (open in a dialog) DOI: 10.1615/IHTC10.4750
pages 165-170

要約

Pool boiling from horizontal tubes with smooth and enhanced surfaces has been experimentally investigated in pure refrigerant R-113, pure R-ll, and mixtures of R-ll and R-113 of approximately 25, 50, and 75% R-113 by mass. Instrumented tubes were electrically heated and mounted horizontally in a pool of a saturated refrigerant at near atmospheric pressure. The enhanced surfaces were a knurled surface (Wolverine's Turbo-B) and a porous surface (Linde's High Flux). Values of the heat flux for a given wall superheat in pure fluids generally were 2 to 10 times larger for the enhanced surfaces than for the smooth surface. The heat transfer performance for each of the enhanced surfaces was affected differently by changes in the porosity, wall superheat, and fluids, which was considered to be the result of different heat transfer mechanisms: nucleate boiling and thin film vaporization. The performance of all three surfaces decreased in fluid mixtures, with the largest degradation occurring in a mixture of 25% R-ll/75% R-113. The enhanced surfaces consistently performed better in the fluid mixtures than the smooth tubes. The degradation in the smooth tube heat transfer coefficients obtained in fluid mixtures depends on the difference between the liquid and vapor molar concentration.