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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EXPERIMENTAL INVESTIGATION OF CONDENSATION HEAT TRANSFER CHARACTERISTICS INSIDE THREE DIMENTIONAL ENHANCED TUBES

Get access (open in a dialog) DOI: 10.1615/IHTC16.cod.023153
pages 2211-2218

Sinopsis

An experimental investigation was conducted to evaluate the tubeside condensation of R410A in three enhanced heat transfer tubes (1EHT-1, 1EHT-2 and 4EHT) . All three enhanced tubes are comprised of a primary and secondary enhancement structure; the 1EHT tubes (1EHT-1 and 1EHT-2) were developed by modifying surface geometries with a combination of larger dimples and smaller petal-like dimples; the 4EHT tube is composed of rectangular dimples and linear ridges. Experiments were performed for a saturation temperature of 318 K; with mass flux ranging from 150 kg/m2s to 460 kg/m2s; inlet quality ranging from 0.2 to 0.8. Values of the heat transfer coefficient for all the tubes increase as the mass flux increases; slowly increasing for G ≤ 250 kg/m2s and increasing more rapidly for higher rates of mass flux. Maximum heat transfer performance occurs in the 1EHT-1 tube with the condensation heat transfer coefficient of the 1EHT-1 tube being 2.0 - 3.0 times larger than a smooth surface tube; the 4EHT tube demonstrates better performance than the 1EHT-2 tube, with the range of the condensation heat transfer coefficient for the two tubes being approximately 1.2 - 2.0 times that of the smooth tube. This enhanced performance is the result of an increased heat transfer surface area and additional enhancement occurs because the surface structure generates secondary flows, increases turbulence and produces a boundary layer disruption. For all test conditions, will produce an increase in the heat transfer coefficient when compared to the performance of a smooth tube.