| Project/Area Number |
19K14904
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 19020:Thermal engineering-related
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| Research Institution | Kanagawa University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 核沸騰 / ミクロ液膜 / 気泡の合体 / 気泡間液膜厚さ / 気泡間液膜 / 沸騰熱伝達 / レーザー干渉法 / レーザー消光法 |
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| Outline of Research at the Start |
本研究は純水中における沸騰冷却の限界である1 MW/m2のさらなる向上を目指し，高熱流束除熱における沸騰伝熱機構を解明することを目的とする．沸騰伝熱機構の解明により，最終的に除熱能力の向上，すなわち冷却技術促進による電子機器の冷却やボイラーといった熱機器の大幅な省エネルギー化へとつなげられる．沸騰伝熱における未解明な点は，熱輸送の定量評価，気泡相互干渉が伝熱に及ぼす影響，発泡核等の伝熱面性状に起因する問題等が挙げられる．本申請では上記課題のうち前者の2つ，すなわち①沸騰伝熱機構の把握，②気泡相互干渉の影響の把握について申請者の持つ最先端の薄液膜測定技術を用いて研究を行う．
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| Outline of Final Research Achievements |
In this study, we clarified the influence of bubble interference on boiling heat transfer by using the thin liquid film measurement method we have developed so far through the following two tasks. (1) To understand the process from the formation to the disappearance of a thin liquid film with extremely good heat transfer formed just below a boiling bubble. (2) Precise measurement of the thickness change of the liquid film between bubbles during the coalescence process is carried out to clarify the distribution of the thickness between bubbles and its change characteristics. As a result, the dynamic behavior of the thin liquid film on the heat transfer surface and the evaporation process under high heat flux conditions with bubble coalescence were observed. The influence of the bulk liquid temperature on the bubble coalescence process was clarified, and the trend of the liquid film thickness between bubbles during the bubble coalescence was also clarified.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究を通して，気泡合体を伴う高熱流束条件下における伝熱面上の薄液膜の動的な挙動および蒸発過程の観察が出来た．このことは，伝熱面への液の供給といった核沸騰伝熱の限界を明確にするために非常に重要な情報となる．また，気泡合体過程におけるバルク液温の影響を明らかにすることで，気泡合体時の気泡間液膜厚さの傾向を明らかにした．これは，気泡の合体という素過程の合体条件を明らかにする上で欠かせないデータとなる．
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