| Project/Area Number |
11650179
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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 |
NISHI Michihiro Kyushu Inst.Tech., Mechanical Engineering Dept., Professor, 工学部, 教授 (80038588)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Kouichi Kyushu Inst.Tech., Mechanical Engineering Dept., Research Associate, 工学部, 助手 (00274548)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Fluid Machinery / Turbopump / Mini Pump / Hydraulic Performance / Design Concepts / Impeller / Performance Test / Clearance / ポンプ / 性能 |
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| Research Abstract |
Regarding those turbo-pumps of impeller diameter between several millimeter and 50 mm as mini size pumps, this research project aims to develop the hydrodynamic basis of a mini pump having high performance and applicability. To achieve the objective, we have studied the usefulness and effectiveness of the following proposed design-concepts experimentally and numerically :
(1) Selection of higher driving speed of pump
(2) Selection of semi-open type impeller (without front shroud)
(3) Selection of greater number of blades and blade exit-angle
(4) Selection of exit-to-inlet area ratio of impeller less than 1
From two years' research work, the following major conclusions are obtained :
1. It is clarified that a mini turbopump having the internal efficiency greater than 60 % is possible. It is noted that this value is greater than that shown in various textbooks.
2. Experimental results indicate that the slip factor takes the value larger than 0.9 and the greater power input will be possible by u
… More
se of the present design concepts for mini pump.
3. The similarity law is observed in the pump characteristics for a rotational speed greater than 4,000 rpm. This speed corresponds to the Reynolds number being 1.2 × 10^5, which almost agrees with the description shown in the literatures. Thus, a high speed pump is desirable for the mini size from the viewpoints of not only the Reynolds number effects but the reduction of loss fraction of mechanical seal.
4. It is shown that the numerical turbulent flow analysis based on Reynolds Averaged Naiver Stokes equations with k-ω turbulence model will be reasonably applicable to study the hydraulic performance of mini impeller.
5. The effect of axial clearance between the impeller tip and the casing wall on the hydraulic performance is satisfactorily predicted by the analysis.
6. The bypass method to return some amount of flow from the exit of the pump to the suction pipe is usable to some extent to improve unstable Q-H curve in the low flow region.
7. Though the present test results showed that the pump efficiency of closed impeller (with shroud) was better than that of semi-open impeller (without shroud), the further study is expected to explain them reasonably.
8. It is confirmed from the present experimental and numerical study that the hydraulic performances including the axial clearance effect will be varied greatly depending on design methods, even if we selected the nearly identical specific speed and diameter. Less
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