科研之友
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摘要
Surface physicochemical properties, including wettability and micro- and nanoscopic roughness, play an important role in boiling heat transfer. In the paper, we consider the bubble formation on a copper wire coated with superhydrophobic micro patterns. Distinctive non-wetted micropatterns were fabricated by the common soft lithography process integrated with a hydrophobic coating method (Larmour et al., 2007) that yields a double-roughness surface with the water contact angle larger than 170 degrees. The width of each pattern was 100 pm and the pitch along the wire was 3 mm. Unlike the previous studies mostly conducted on flat surfaces, the micro-sized copper wire (150 gm in diameter) greatly facilitated the observation of the bubble dynamics details. Standard saturated pool boiling was conducted with a prior-degassing procedure. For comparison, the same boiling processes were conducted on a bare copper wire as well as a uniformly coated superhydrophobic wire. The bubble behaviors were visualized, and the advantages of the micro patterns in bubble distribution, nucleation and detachment were proved.
