| Project/Area Number |
04452142
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| Research Category |
Grant-in-Aid for General 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 | KYUSHU UNIVERSITY |
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Principal Investigator |
INOUE Masahiro KYUUSHU UNIVERSITY,DEPARTMENT OF ENERGY & MECHANICAL ENGINEERING,PROFESSOR, 工学部, 教授 (90037903)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Yoshiyisa KYUSHU UNIVERSITY,DEPARTMENT OF ENERGY & MECHANICAL ENGINEERING,PESEARCH ASSISTA, 工学部, 助手 (40037883)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1992: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | Turbomachine / Rotating stall / Flow diagnosis / Flow control / Piezoeilectric actuator / Micro actuator / Karman vortex / Entrainment of frequency / 引き込み現象 / 圧力変動 / 予見制御 |
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| Research Abstract |
This study is a fundamental one to investigate possibility of artificial intellectualization of turbomachines by sensing an abnormal flow condition locally and by controlling the flow automatically by the use of micro-actuators.
As a sensing technology, we took up a problem of detection of pre-rotating-stall phenomena, which is the most important problem in abnormal flow conditions in turbomachines. Statistical characteristics of pressure fluctuation on the casing wall of two axial flow compressor rotors and a diagonal flow impeller were investigated experimentally to find a detector or the pre-rotating-stall phenomena. Near stall, the casing wall pressure across a flow passage near the leading edge is characterized by a highly unsteady region where low-momentum fluid accumulates. The periodicity of the pressure fluctuation with blade spacing disappears and an alternative phenomenon comes into existence, which supports the disturbance propagating at a different speed from the rotor revo
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lution. The pre-rotating-stall phenomena can be detected by monitoring collapse of the periodicity in the pressure fluctuation. To represent the periodicity qualitatively, a practical detection parameter was proposed, which is easily obtained from signals of a single pressure sensor installed at an appropriate position on the casing wall during operation of a compressor.
As a flow control technology with micro-actuators, effects of micro-excitation of boundary layr on flow conditions around a cylindrical bluff body have been investigated experimentally. The micro-excitation is accomplished by oscillating sidewall surfaces of the body in the cross-flow direction using piezoelectric actuators. The excitation frequency covers below and above a natural vortex shedding frequency from the body and Reynolds number ranges from 5.25*103 to 2.31*104. The excitation of downstream surface of sidewalls affects not much entrainment of vortex shedding frequency. However a substantial amount of entrainment of vortex shedding frequency has been observed by exciting upstream surface of sidewalls where a short laminar separation bubble exists. This is due to delay of boundary layr separation. Less
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