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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

CONDENSATION OF CFC-113 WITH DOWNFLOW IN VERTICAL, INTERNALLY ENHANCED TUBES

Get access (open in a dialog) DOI: 10.1615/IHTC11.430
pages 347-354

Аннотация

Accurate repeatable heat-transfer measurements have been obtained for condensation of CFC-113 with downflow inside enhanced "'micro-fin" tubes. The heat-transfer rate to the test condenser tube was calculated from the coolant flow rate and temperature rise, the latter measured using a ten-junction thermopile with careful attention paid to adequate mixing and isothermal immersion of the thermopile leads. The vapour-side heat-transfer coefficient was found from the directly measured tube wall temperature using thermocouples embedded in the tube wall.
One plain tube and three different enhanced tubes with different fin heights were tested. Enhancement ratios (i.e. heat-transfer coefficient for the enhanced tube divided by that for a smooth tube at the same vapour-side temperature difference and vapour inlet velocity), between 1.6 and 5.6 were found, with values depending on vapour-side temperature difference and vapour inlet velocity.