Interfacial nanobubbles were first speculated in 1994 and experimentally confirmed in 2000 by atomic force microscopy (AFM) measurements. It was recently proposed that the onset of boiling with the very low superheat on hydrophobic surface could be explained by assuming the existence of interfacial nanobubbles. To reduce the superheat and enhance the reliability of boiling heat transfer, the control of the generation of interfacial nanobubbles is indispensable. In this study, we measured the interfacial nanobubbles by AFM and examined the influence of surface wettability and nanostructure on their generation. First, we measured the spherical-cap shaped nanobubbles generated on the HOPG surface. It was observed that the nanobubbles only generate on the hydrophobic terraced area and do not cross the nanosized hydrophilic steps. Next, we prepared the hydrophilic-hydrophobic hybrid surfaces and generated the nanobubbles on those. As a result, the range of nanobubble generation clearly changed by the difference of wettability between adjacent surfaces. These results show that the generation of interfacial nanobubbles can be controlled by the surface processing of the substrate and can be expected to be applied to boiling heat transfer.
|ジャーナル||International Heat Transfer Conference|
|出版ステータス||出版済み - 2018|
|イベント||16th International Heat Transfer Conference, IHTC 2018 - Beijing, 中国|
継続期間: 8 10 2018 → 8 15 2018
All Science Journal Classification (ASJC) codes