2004 Fiscal Year Final Research Report Summary
Unsteady Behaviors and Bifurcation Phenomena observed in an Impeller-Rotating Shaft System of a Centrifugal Fluid Machinery
| Project/Area Number |
14550162
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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 | Waseda University |
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Principal Investigator |
OHTA Yutaka Waseda University, School of Science & Engineering, Professor, 理工学術院・理工学部, 教授 (50211793)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Fluid Machinery / Unsteady Phenomena / Bifurcation Phenomena / Taylor Vortex / Aeroacoustics / Rotating Stall |
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| Research Abstract |
Concerning about centrifugal as well as axial-flow type fluid machinery, the following unsteady phenomena appearing in an impeller-rotating shaft system are investigated by experiments and also by the CFD analyses : (1)The unsteady behavior and bifurcation of the Taylor vortex flow generated in a mechanical bearing. (2)The aerodynamic noise generated in a centrifugal type of fluid machinery system and its noise source bifurcation. (3)The rotating stall pattern of the axial-flow compressor and bifurcation of stall cells. The detailed contents are as follows.
(1)In order to understand the unsteady behavior of the Taylor vortex flow generated between two rotating cylinders with large eccentricity, a 3-D N-S simulation was carried out. As a result, while clarifying unsteady bifurcation of the cell, the first attempt which controls a cell using a jet from an outer cylinder was also performed. Furthermore, an unsteady temperature field and cooling technology were also examined by applying energy equation. The experimental apparatus for verifying numerical results was manufactured, and the preliminary experiment was conducted. (2)With respect to the noise generated from centrifugal fluid machines, the sound source characteristics and their bifurcation at the time of changing various operating conditions were experimentally investigated. Particularly, the noise source extent of the high-order BPF components shows irregular movement and bifurcation against the change of the operating conditions. Moreover, the numerical analysis aiming at understanding this phenomenon in detail was started. (3)Also about the rotating stall of a three-stage axial flow compressor and the bifurcation of a stall cell, by changing various stagger angles of rotor and stator, all kinds of stall inception patterns and the bifurcation of the stall cell were able to be confirmed. The active control technology of the compressor rotating stall by sensing the stall inception sign was also examined.
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Research Products
(12 results)
