| Project/Area Number |
09650253
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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 |
Thermal engineering
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| Research Institution | Keio University |
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Principal Investigator |
HISHIDA Koichi Keio University, Faculty of Science and Technology., Professor, 理工学部, 教授 (40156592)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Laser technique / Non-intrusive measurement / Velocity measurement / Shape measurement / Non-spherical particle / LDV / PDA |
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| Research Abstract |
It is well known that Thorns effect in non-Newtonian fluid causes the drag reduction. Recently it has been reported that an addition of small amounts of surfactants also provided the same effect on the drag reduction. The characteristics of drag reduction flow can transport the long distance thermal medium with low energy loss. The mechanism of drag reduction flow has been stilt unexplored, especially for the turbulent flow condition that appears in a practical application. In the present study, experimental study has been performed on the behavior of micelle structure with reversible transform of polymer, and a controlling technique for thermo-fluid phenomena has also developed by using surfactant.
Heat transfer characteristics of a dilute surfactant/water solution in a two dimensional channel has been experimentally investigated. Temperature profile measurements in the thermal boundary layer were also made. It was found that high diffusivity layer exists near the wall in the drag reducing thermal boundary layer and that the time scale of temperature fluctuation in the layer becomes smaller as increased of wall heat flux. In order to increase the heat transfer coefficients, the mesh plug was used to exert high shear stress to destroy micelle structure in the surfactant solution so that turbulence could be produced. The mesh plug indicated that the high heat transfer region had the same turbulent intensity as that of water flow. The mesh helped to create high wall shear stress and therefore to destroy the rod-like micelles for introducing turbulent. It was found that the turbulent intensities of the velocity gradually decreased to the same as those of drag reduction flow downstream form the mesh because the mesh plug only produced a local high shear stress. This technique can be applied for effective heat transfer augmentation in a drag reduction flow.
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