| Project/Area Number |
02650444
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
資源開発工学
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| Research Institution | Hokkaido University |
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Principal Investigator |
ASAKURA Kuniomi Hokkaido University, Fac. of Engineering, Research Associate, 工学部, 助手 (20002305)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Solid-Liquid Flow / Multiphase Flow / velocity Profile / Concentration Profile / Fluctuations / Vertical Pipe Flow / 固液混相流 / 乱れ / 電極法 / スペクトル |
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| Research Abstract |
Local mean profiles of solid phase were obtained in vertical upward and downward flows using three sizes of glass beads and a size of polystyrene beads. The profiles were measured by a conductive probe.
The velocity profiles of the solid phase were affected by terminal settling velocity, mean velocity and mean concentration of solids. Blunting and sharpening of velocity profiles were observed with particles of high setting velocity in upward and downward flows, respectively.
Concentration profiles of the particles with high terminal velocities appear to be explained by Saffmam lift forces in both upward and downward flows. Concentration profiles of the polystyrene beads seems to be explicable by Bagnold's dispersive stress due to its strong effect at high concentration. The 0.48 mm glass beads tended to cluster near the pipe wall in both the upward and downward flows.
Concentration fluctuations were analyzed up to 320 in wave number to eliminate effects of the probe wake. The relative intensity decreased with distance from the wall and with decrease in particle diameter. Particle diameter had a stronger effect on the relative intensity than terminal settling velocity. Integral scale ranged from about 1 to 3 cm and decreased with distance from the pipe wall. The scale was not in order of terminal settling velocity.
The effect of velocity on the integral scale was clear, but the effect of the discharge concentration was minor.
The concentration profiles of 0.48 inm glass beads suggest that further efforts should be made to study aggregative structure of those flows.
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