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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

CONDENSATION HEAT TRANSFER OF R-134A ON SINGLE HORIZONTAL THREE-DIMENSIONAL STRUCTURED TUBES

Get access (open in a dialog) DOI: 10.1615/IHTC16.cod.023874
pages 2485-2492

Sinopsis

Condensation heat transfer coefficients were experimentally investigated on four structured tubes having three-dimensional fin geometries on the outside and helical ribs on the inside of the tubes. Tests were conducted using R-134a at a saturation temperature of 35°C. The outside diameter of the tubes is 19 mm and the length of the test section is 1002 mm. Heat flux and cooling water flow rate are varied in a wide range. Shell-side heat transfer coefficients are obtained from overall heat transfer data and the implementation of commonly used correlations for tube- and shell-side heat transfer. Experimental results for a plain tube are in good agreement with Nußelt film theory. During the tests of the structured tubes, considerable enhancement for shell-side and tube-side heat transfer coefficients are observed as compared to the plain tube. Enhancement factors for condensation heat transfer are ranged from 14.8 to 27.4 at a heat flux of 20 kW/m². Due to differences in outer fin geometries, significant impact of small scale parameters on condensation performance was identified.