2007 Fiscal Year Final Research Report Summary
Mass production method of micron liquid droplets by active control of cavitation flow
| Project/Area Number |
18560151
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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 | Hirosaki University |
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Principal Investigator |
INAMURA Takao Hirosaki University, Hirosaki University, Graduate School of Science and Technology, Professor (10143017)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Thermal Engineering / Fluid Mechanics / Spray Technology / Energy Efficiency / Liquid Atomization |
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| Research Abstract |
This research aims to develop a new mass production method of micron liquid droplets by using the active control of the cavitation flow. The turbulences are induced in the liquid flow inside a nozzle by the collapses of cavitation bubbles, and they promote the atomization of a liquid jet after injection from the nozzle. Firstly, the most suitable form of a cavitation flow for the atomization was obtained. Next, the atomization conditions were clarified to obtain the most suitable form of a cavitation flow. Finally, the new airblast atomizer with the active control of a cavitation flow was developed, and its spray characteristics were measured. From above experiments, the following results were obtained:
1. The cavitation occurs at low back pressure and high Reynolds number, and the form of a cavitation flow can be classified by only the cavitation number.
2. With the decrease of a cavitation number, the form of a cavitation flow changes from the smooth flow, cloud cavitation flow, sheet cavitation flow and hydraulic flip.
3. Under the low velocity of an atomization air, the form of a cavitation flow affects greatly the spray characteristics. The sheet cavitation flow promotes the atomization and the hydraulic flip makes the atomization worse.
4. Under the high velocity of an atomization air, the effect of a form of a cavitation flow on the mean diameter gets smaller, and that of a velocity of an atomization air becomes dominant.
5. In the present experiments, the minimum mean droplet size is about 20?m. It seems to be possible to make the minimum mean droplet size smaller than 20?m by devising the impinge method between the liquid and the atomization air.
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