| Project/Area Number |
05650249
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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 |
Dynamics/Control
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| Research Institution | Kurume Institute of Technology |
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Principal Investigator |
KUBO Shozo Kurume Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (10038078)
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| Co-Investigator(Kenkyū-buntansha) |
SUMI Seinosuke Kurume Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (10037947)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1994: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Centrifuge / Divided cavity / Two liquids type / Liquid force / Self-excited vibration / Rotor / External damping / Boundary layr / 流体関連振動 / 回転流体 / 減衰力 / 粘性 |
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| Research Abstract |
A high-speed rotor containing the cavity, which is divided into fan-shaped compartments and filled with two kinds of liquids of different density, can exhibit unstable behavior under certain conditions. The system considered simulates a centrifuge of two liquids type, in which the cylindrical cavity is divided into fan-shaped compartments.
This paper is concerned with the theoretical and experimental study of dependence of the unstable region on the external damping applied to the rotor.
The self-excited vibrations with the frequency of about the critical speed of tha system can occur only in the regions where the rotor speed is nearly equal to the sum of the critical speed of the system and the natural frequencies of the liquids in the cavity. With an increase in the damping the self-excited vibrations become weak, and the range of the unstable regions decreases. Such unstable regions shift to higher rotor speed with an increase in the number of partitions, until the system becomes stable at any rotor speed when the corresponding natural frequencies of the liquids exceed the rotor speed. When the number of partitions increases, the self-excited vibrations are apt to suppressed by very small damping. In most cases the self-excited vibrations induced by the liquid motions of the higher (second) mode are not so strong that they are apt to suppressed by small damping easily or they are not observed. In the case where the difference in density between the liquids is not large, the range of the unstable region is relatively narrow.
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