| Project/Area Number |
09650195
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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 | KYUSHU INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
TOMITA Yuji KYUSHU INSTITUTE OF TECHNOLOGY,Faculty of Engineering, Department of Mechanical and Control Engineerig, Professor, 工学部, 教授 (60039104)
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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 |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Multi-phase flow / LDV / Powder jet / Air Entrainment / Numerical simulation / Terminal setting velocity / Axial velocity profile / Spreading width / LDV計測 / ガラスビーズ / 落下速度 / 半径方向速度 / 数密度 |
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| Research Abstract |
When powder is discharged from the bottom orifice of vessel under gravity, the ambient atmosphere is entrained into the powder jet. in this research, we experimentally and numerically examine the flow mechanism of the free falling powder jet. A laser Doppler velocimeter is used for the measurement. The particles used are glass beads with a mean diameter of 454 mum .It is found that the free falling velocity of the powder jet is larger than that of the single particle in the still air and increases with an increase in the mass flow rate of powder. This is because there exists a downward air stream in the powder jet by the entrained air. At a long distance from the orifice, the velocity profile of powder jet relative to the local free falling velocity of the single particle is similar to that of a single-phase free turbulent jet. Near the orifice a potential-like profile is observed. Based on the present measurement we estimate the axial velocity profile of powder jet and the entrained air flow rate. The spread of the powder jet is very small as compared with that of the single-phase turbulent jet. The numerical simulation is performed based on Lagrangian modeling for particles and Eulerian modeling for air flow. We consider particle-particle collision, drag force, gravity force and transverse force due to the particle spin and to the velocity gradient of air flow, and apply a laminar flow model. The present simulation well explains our measurement in terms of particle and air velocity profiles and jet spreading.
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