刊名:International Journal of Heat and Mass Transfer
出版年:2017
出版时间:May 2017
年:2017
卷:108
期:part_PA
页码:1126-1139
全文大小:1965 K
卷排序:108
文摘
Filmwise condensation on horizontal surface with asymmetric structures is studied. A transient film rise within an asymmetric structure (ratchet) is characterized. Film growth on an asymmetric ratchet is compared against a symmetric ratchet. Numerical results are validated by visualization experiments of condensate growth. Condensate rises preferentially towards the steeper slope of the ratchet. Condensate rise rate increases with an increase in ratchet surface asymmetry. Condensate growth is a function of capillary number. Condensate growth rate is independent of Bond number for ratchet pitches < 2.4 mm. Surface heat transfer coefficient increases with increase in surface asymmetry. Surface heat transfer coefficient increases fourfold from pitch of 2.4 mm to 80 µm.