| Project/Area Number |
16K06103
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 二成分水溶液 / 限界熱流束 / 可視化測定 / 沸騰 / ドライアウト / 二成分流体 / プール沸騰 / 可視化 / 表面活性剤 / 濃度分布 / マランゴニ対流 / 熱工学 |
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| Outline of Final Research Achievements |
The CHF of the mixtures considerably increases when small amount of alcohols are added to water. To examine the mechanism of CHF enhancement, this research visualized the boiling behaviors of water, binary aqueous mixtures of alcohols (2-propanol, butanol, pentanol), and surfactant (Triton-X) using a transparent heating surface. It was found that the dryout expansion on the heating surface was significantly suppressed in the alcohol aqueous solution compared to water, and there was almost no difference between the Triton-X aqueous solution and water.
These results clarified that the CHF enhancement in the binary aqueous mixtures is due to the suppression of surface dryout caused by non-uniform distribution of alcohol concentration formed near the heating surface.
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| Academic Significance and Societal Importance of the Research Achievements |
沸騰の除熱限界である限界熱流束(CHF)は，微量のアルコールを添加することで大きく促進されるため，高熱流束機器の沸騰除熱媒体として利用できる可能性がある．しかし， CHF促進機構は明らかになっていなかった．本研究では，透明伝熱面を用いた可視化測定により，伝熱面上の乾燥領域の拡大がアルコールの添加により大幅に抑制されることがCHF促進をもたらしていることを明らかにした．また，炭素数4以上のアルコール水溶液は極めて低濃度でCHFの大幅な促進をもたらす，効率的なCHF促進媒体であることを明らかにした．
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