Study of breakup and dispersion processes of droplets in supersonic sprays by laser probe
| Project/Area Number |
17K06162
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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 |
Fluid engineering
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| Research Institution | Nagasaki University |
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Principal Investigator |
UEKI Hironobu 長崎大学, 工学研究科, 教授 (30160154)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2017: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | 混相流 / 液体微粒化 / ウエーバー数 / マッハ数 / 流体工学 / 混相流動 / レイノルズ数 |
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| Outline of Final Research Achievements |
The supply pressure to the nozzle was 180 MPa at maximum, and the gas oil was injected into the atmosphere at Bernoulli velocity of 650 m / s and Mach number of 1.9, that is, supersonic velocity. A laser-2-focal velocimeter equipped with a microscale laser probe was used to measure the velocity and size of spray droplets in a breakup process 4 to 15 mm away from a 0.1 mm diameter nozzle hole.
As a result, it was clarified that 90% or more of the droplets measured at the tip of the spray at the initial stage of injection were subsonic, under the condition that the average droplet velocity in the spray reached the supersonic velocity in the middle of the injection period. Since the droplet size at the spray tip is smaller than that in the middle of the injection period, it is considered that the shock wave generated at the spray tip caused the droplet to breakup and slow down.
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| Academic Significance and Societal Importance of the Research Achievements |
高速噴霧による液体微粒化は、ガスタービン・往復動内燃エンジン等の燃料噴霧、噴霧による塗装・洗浄・冷却、医療用ネブライザ、薄膜生成、パウダー製造等、多くの分野で利用されている。噴射圧の増加による微粒化の促進、ならびに超音速噴霧に生じる衝撃波については多数の研究者により報告がなされてきた。
超音速噴霧における液滴の分裂および分散について、これまで報告が存在せず、本研究によって初めて捉えられた。各分野において要求される噴霧特性を実現するための微粒化モデリングの高精度化に役立つことが期待される。
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Report
(4 results)
Research Products
(17 results)
