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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

GRAVITATIONALLY-DRIVEN WICKING CONDENSATION

Get access (open in a dialog) DOI: 10.1615/IHTC16.cod.023656
pages 2447-2454

Sinopsis

Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Filmwise condensation is prevalent in typical industrial-scale systems, where the condensed fluid forms a thin liquid film due to the high surface energy associated with many industrial materials. Conversely, dropwise condensation, where the condensate forms discrete liquid droplets which grow, coalesce, and shed, results in an improvement in heat transfer performance of an order of magnitude compared to filmwise condensation. However, current state-of-the-art dropwise technology relies on functional hydrophobic coatings, for example long chain fatty acids or polymers, which are often not robust and therefore undesirable in industrial conditions. In addition, low surface tension fluid condensates such as hydrocarbons pose a unique challenge since the typical hydrophobic condenser coatings used to shed water (surface tension 73 mN/m) often do not repel fluids with lower surface tensions (< 25 mN/m). We demonstrate a method to enhance condensation heat transfer with gravitationally-driven flow through a porous metal wick which eliminates the need for condensate-phobic coatings. The condensate-filled wick has a lower thermal resistance than the fluid film observed during filmwise condensation, resulting in an improved heat transfer coefficient of up to an order of magnitude and comparable to that observed during dropwise condensation. The improved heat transfer realized by this design presents the opportunity for significant energy savings in natural gas processing, thermal management, heating and cooling, and power generation.