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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Investigation of thick polymer film promoting dropwise condensation mode on dropwise and film coexisting surfaces

Get access (open in a dialog) DOI: 10.1615/IHTC12.550
6 pages

Sinopsis

This paper attempts to examine the possibility of a thick polymer film promoting dropwise condensation to enhance condensation heat transfer characteristics of steam on horizontally divided dropwise and film coexisting (DFC) surfaces. A polymer film with thickness of more than 1 μm was coated on the dropwise parts of the external surface of brass tube. The area ratio of dropwise parts and filmwise parts was fixed at 1:1 for the six surfaces, whilst the division number ranging from 2 to 16. The heat transfer performance of DFC surface increased with the division number increasing. Compared with the bare surface, an enhancement ratio of 1.3 to 4 was realized. Experimental results indicated the condensate ring plays an important part in condensation heat transfer enhancement of DFC surface. Also, The heat transfer enhancement characteristics of dropwise and film coexisting surface depends not only on the surface division numbers, but also on the operating conditions. Accordingly, an optimal condition between surface division numbers and surface subcooling should be determined for practical application.