| Project/Area Number |
16560133
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
HAYAKAWA Michio Hokkaido Univ., Grad.School of Eng., Research Assistant, 大学院・工学研究科, 助手 (80002038)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIKAWA Shigeo Hokkaido Univ., Grad.School of Eng., Professor, 大学院・工学研究科, 教授 (70111937)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Submerged water jet / Cavitation / Organic compounds / Liquid-gas two-phase flow / Fluid compressibility / Microbubbles / 衝撃圧 |
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| Research Abstract |
The present research has been made to develop an alternative cavitating water-jet facility which enables to decompose organic compounds in contaminated water at significantly low jet-operating pressures compared to customarily used submerged water jets. A basic idea in the present work is to utilize shock waves for localizing the occurrence of bubble collapse, which is expected to cause the efficient decomposition of organic compounds dissolved in water. The results of this study are summarized as follows.
1.The decomposition rate of organic compounds dissolved in water increases when the bubbly flow through the water-jet nozzle meets the condition to generate shock waves, although the rate of increase attained so far in the present experiments remains within an extent lower than the initially expected level.
2.Two supplemental means are found to be useful for realizing supersonic bubbly flows in a moderately low range of the flow velocity ; one is the use of artificially generated microbubbles, and the other is the introduction of axisymmetrically rotating motion in the flow upstream the nozzle.
3. Mathematical and numerical analyses of the bubble growth in water show that the cavitation inception can occur at an ambient pressure higher than the so-called critical pressure below which the inception condition is known to be satisfied.
4. A set of space-averaged model equations describing the motion of liquid-gas mixtures, which was recently developed in our laboratory, is applied to the computation of convergent-divergent nozzle flows, and is found as a promising method for the practical calculation of high-speed liquid flows with cavitation.
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