| Project/Area Number |
60420027
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | University of Tokyo |
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Principal Investigator |
OHASHI Hideo Prof., Faculty of Engineering, Universiy of Tokyo, 工学部, 教授 (90010678)
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| Co-Investigator(Kenkyū-buntansha) |
SHOJI Hidenobu Associate Prof., Inst. of Eng. Mechanics, Univ. of Tsukuba, 構造工学系, 助教授 (90126087)
TERUYA Isao Assistant, Faculty of Engineering, Ryukyu University, 工学部, 助手 (10188691)
ICHIKAWA Yasumasa Assistant, ditto, 工学部, 助手 (40134473)
KAWADA Tatsuo Assistant, ditto, 工学部, 助手 (00010851)
MATSUMOTO Yoichiro Associate Prof., Faculty of Engineering, University of Tokyo, 工学部, 助教授 (60111473)
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| Project Period (FY) |
1985 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1987: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 1985: ¥6,900,000 (Direct Cost: ¥6,900,000)
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| Keywords | Two Phase flow / Water tunnel / Viod fraction measurement / Numerical calculation / Airfoil / Cascade / Pump / Point electrode probe / 揚力特性 / 数値解析 / 減速翼列 / ボイド分布 / 数値流体力学 / ターボ機械 / 探針プローブ |
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| Research Abstract |
As a basic research of two phase flow performance of turbomachinery, twodimensional flow around an airfoil and cascade of airfoils in air/water two phase condition was studies experimentally and theoretically. The results are summarized as follows:
1. Construction of two-phase flow water tunnel Air/water recirculating water tunnel with test section of 200x100 mm, max. velocity of 8 m/s, mas. void fraction of 10 % was designed and built. Since no similar test tunnel has been built elsewhere, it required several testing and redesign of air injection device and reducing nozzle, before a satisfactorily uniform distribution of void fraction was obtained at the test section . Air is injected to water upstream of the reducing nozzle through 9 thin blades made of sintered powder metal. Both isolated airfoil and cascade of airfoils can be installed in the test section.
2. Development of measurement system for local void fraction The system is composed of point electrode probe, x-y auto-traversing
… More
device and signal processor. Spatial distribution of void fraction and void size can be measured efficiently.
3. Flow around an airfoil in two phase Flow flow around a NACA 4412 airfoil was measured for attack angle of 0 - 15゜and void fraction of 0 - 10 %. The spatial distribution of void fraction was measured by point electrode. Lift and drag characteristics were determined from pressure distribution over the airfoil. Due to the pressure gradient around the airfoil, the redistribution of bubbles occurs in such manner that bubble accumulate on the suction side while they are expelled from the pressure side. This gives rise to an unusual lift-attack angle characteristics.
4. Numerical simulation Based on the dynamics of bubbles the basic equations of flow field were formulated, taking the slip between bubbles and surrounding water into account. The direct comparison between theory and experiment is still not complete and will be done in the near future.
The study will be expanded to the case of cascade after the basic understanding is obtained on the two phase flow phenomena around an isolated airfoil. Less
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