| Project/Area Number |
04555041
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
OBA Risaburo Tohoku University, Institute of Fluid Science, Professor, 流体科学研究所, 教授 (40006169)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIGE Tadashi Kurimoto Ltd., Sumiyoshi Factory, General Magager, 住吉工場, 部長
SOYAMA Hitoshi Tohoku University, Institute of Fluid Science, Research Associate, 流体科学研究所, 助手 (90211995)
SATO Keiichi Kanazawa Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50113030)
ITO Yukio Hchinohe Institute of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (70006196)
IKOHAGI Toshiaki Tohoku University, Institute of Fluid Science, Associate Professor, 流体科学研究所, 助教授 (90091652)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1993: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1992: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Valve / Butterfly-valve / Cavitation / Erosion / Vortex / Shear region / Vibration / Noise / 上流キャビテータ |
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| Research Abstract |
In order to make high reliability valves, which work safety in extreme flow conditions, we systematically observed the flow pattern and precisely measure the cavitation damage arisen around the butterfly-valve, the gate-slot and the hollow-jet-valve. In our study, we tool up the butterfly valve, because the butterfly valves are inexpensive, quite simple in construction, and can control the flow rate smoothly. We observed the flow pattern around a model of the butterfly-valve and measure the cavitation-induced-pressure-pulses by means of a pressure sensitive film and a hydrophone. The obtained results are summarized as follows :
1. As a result of the observation of the flow pattern around the butterfly valves by means of a highspeed video camera, whose maximum framing rate is 40, 500 frames per second, the erosion on the surface of the downstream-pipe is closely related to the singular longitudinal vortex cavitation associated the high shear region between the orifice jet and the recirculating region. The vortex cavitation develops into the severely erosive cavitation in the recirculating region with combining the several vortex cavitations.
2. The above-mentioned cavitation is weak as the projection is set on the orifice-side-surface of the butterfly valve, because the orifice jet becomes weak to be disturbed. We also make clear the cavitation-impulsive-pressures by means of the pressure sensitive film, and the cavitation noises by means of a hydrophone.
3. In the case of the eccentric butterfly valve, in which it is very convenient to change the valve washer, there are two types on the setting to the flow direction, namely the convex part sets on the upstream or the downstream to the valve stem. It is shown that there is no difference on the flow rates between the two types of the setting.
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