| Project/Area Number |
15560146
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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 | OKAYAMA UNIVERSITY |
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Principal Investigator |
GOTOH Kuniaki OKAYAMA UNIVERSITY, Dept.Applied Chemistry, Professor, 工学部・物質応用化学科, 教授 (20215487)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Multiphase flow / Particle / Agglomeration / Flow resistance / Pressure drop / Drag reduction |
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| Research Abstract |
It is known that a surfactant solution with appropriate counter ion induces the structure of fiber-like micelles in a shear flow field. When the structure is induced, the drag of the pipe flow is reduced. Based on the fact, we presumed that structure of agglomerated particles in a particle suspension also causes the same effect. Thus, we attempted to reduce the pressure drop of the suspension flow by adding a polymer flocculant. In this study, we investigated the change of the pressure drop of the pipe flow with the flocculant concentration. The change of the drag was evaluated by the drag reduction rate defined by the ratio of the difference of the friction factor between water flow and suspension flow to the friction factor of water flow.
It was found that the suspension with polymer flocculant caused the drag reduction under the conditions of particle concentration 1 and 10vol%. In the same flocculant concentration, the water solution of the flocculant (=without particles) also cause
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d the drag reduction. However, the drag reduction rate of the solution was less than that of the suspension with flocculant under certain conditions. The fact shows that the particle enhances the drag reduction.
The effect of the flocculant on the drag reduction decreases with time. One of the main causes is the cut of polymer chain by a shear flow field and/or by the equipment like a pump. It was found that the adding a flocculant into a particle suspension causes larger enhancement than the adding particles into the flocculant solution. It leads to an assumption that inhomogeneous agglomeration attributes to the enhancement. Thus, it was expected that the change of agglomeration from inhomogeneous to homogeneous is another cause of the decrease of the effect.
From the observation of the flocculate in a stationary fluid, it was found that independent agglomerations were formed when the drag reduction was enhanced. The fact shows that the drag reduction is attributed by agglomerated particles. It leads to an expectation that the drag reduction can be achieved in any other solid-liquid suspension if proper agglomeration is formed. Less
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