2000 Fiscal Year Final Research Report Summary
Collision Dynamics of Droplets Impinging into a Hot Solid
| Project/Area Number |
11650739
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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 |
Material processing/treatments
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
FUJIMOTO Hitoshi Kyoto University, Energy Science, Research Associate, エネルギー化学研究科, 助手 (40229050)
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| Co-Investigator(Kenkyū-buntansha) |
ISHII Ryuji Kyoto University, Energy Science, Professor, エネルギー化学研究科, 教授 (20026339)
TAKUDA Hirohiko Kyoto University, Energy Science, Associate Professor, エネルギー化学研究科, 助教授 (20135528)
HATTA Natsuo Nippon Bunri University, Engineering, Professor, 工学部, 教授 (30026041)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Collision of droplets / Weber number / Reynolds number / boiling / free surface / numerical simulation |
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| Research Abstract |
The collision of liquid droplets with a solid has been studied experimentally. The time evolution of the liquid/solid contact area as well as the shape of droplets has been observed by means of a flash-photographic method using two video cameras. It has been found that some air between the solid surface and the incoming droplet is entrapped at the moment of impact. In the case where the solid temperature is high (=450 ゜C) , numerous vapor bubbles appear at the liquid/solid interface after the collision. The bubble formation due to the entrapment of air has been examined for various experimental conditions. Water, and ethanol are used as test liquid. The droplet diameter is 2.4 mm for water and 1.9 mm for ethanol. The impact velocity varies from 0.8 to 3.1 m/s. The entrapment of air has been observed for both liquids under all conditions in the present study.
The collision of liquid droplets with a solid has also studied theoretically. The system of Navier-Stokes equations for incompressible fluid flow in the axial coordinate system is solved by means of a finite difference method. The effect of surface tension, gravity, and wettability between the liquid and the solid is taken into account. The deformation behavior of a single drop onto a solid is examined and compared to the experimental data for model validation. The physics of interaction phenomena of droplets is investigated theoretically.
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