2015 Fiscal Year Annual Research Report
バブルダイナミクスに及ぼす表面性状効果を利用する最適沸騰面に関する研究
| Project/Area Number |
26889044
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| Research Institution | Kyushu University |
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Principal Investigator |
Shen Biao 九州大学, 学内共同利用施設等, 研究員 (80730811)
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| Project Period (FY) |
2014-08-29 – 2016-03-31
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| Keywords | プール沸騰 / 親水撥水複合 / 沸騰開始 / 減圧下沸騰 / 数値シミュレーション / 拡散界面法 / マッハ・ツェンダー干渉計 |
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| Outline of Annual Research Achievements |
1. Experimental study of boiling heat transfer on a biphilic surface
We have designed and fabricated a heterogeneous boiling surface with spatially varying wettability, which exhibits exceptional heat transfer performance at various pressures. Specifically, at atmospheric pressure, the onset of nucleate boiling is lowered significantly (to negative levels) on a superhydrophilic (CA<10°) TiO2 surface coated with an array of hydrophobic PTFE (Polytetrafluoroethylene, CA>120°) spots of 6-mm diameter and 7-mm pitch. The facilitated boiling incipience extends boiling to low-heat-flux applications as an effective means of heat transfer. At reduced pressures, on the other hand, technical limitations on boiling, such as large incipience temperature overshoots, have been greatly mitigated by using a copper boiling surface sputter-coated with 5-micron Ni/TFEO (Tetrafluoroethylene oligomer) particles of various designs. Additionally, we have used a laser Mach-Zehnder interferometer to observe thermocapillary convection above the biphilic surface, which contributes to enhanced heat transfer with high concentrations of dissolved gas.
2. Numerical simulation of bubble dynamics on a biphilic surface
We have performed a numerical study of phase transition of a two-component system by using a diffuse-interface method. The results show contrasting bubble behaviors, from firm attachment under dynamic equilibrium to partial departure (pinch-off) from the biphilic surface, as the concentration of dissolved gas increases.
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| Research Progress Status |
27年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
27年度が最終年度であるため、記入しない。
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[Journal Article] Bubble activation from a hydrophobic spot at “negative“ surface superheats in subcooled boiling2015
Author(s)
Shen, B., Suroto, B.J., Hirabayashi, S., Yamada, M., Hidaka, S., Kohno, M., Takahashi, K. and Takata, Y.
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Journal Title
Applied Thermal Engineering
Volume: 88
Pages: 230
DOI
Peer Reviewed / Int'l Joint Research
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