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    Unsteady Flow and Whirl-Inducing Forces in Axial-Flow Compressors: Part II—Analysis

    Source: Journal of Turbomachinery:;2001:;volume( 123 ):;issue: 003::page 446
    Author:
    S. J. Song
    ,
    D. C. Wisler
    ,
    F. F. Ehrich
    ,
    Z. S. Spakovszky
    ,
    A. F. Storace
    ,
    H.-W. Shin
    ,
    M. Martinez-Sanchez
    ,
    B. F. Beacher
    DOI: 10.1115/1.1370165
    Publisher: The American Society of Mechanical Engineers (ASME)
    Abstract: An experimental and theoretical investigation was conducted to evaluate the effects seen in axial-flow compressors when the centerline of the rotor becomes displaced from the centerline of the static structure of the engine, thus creating circumferentially nonuniform rotor-tip clearances. This displacement produces unsteady flow and creates a system of destabilizing forces, which contribute significantly to rotor whirl instability in turbomachinery. These forces were first identified by Thomas (1958. Bull. AIM, 71 , No. 11/12, pp. 1039–1063.) for turbines and by Alford (1965. J. Eng. Power, Oct., pp. 333–334) for jet engines. In Part I, the results from an experimental investigation of these phenomena were presented. In this Part II, three analytic models were used to predict both the magnitude and direction of the Thomas/Alford force in its normalized form, known as the β coefficient, and the unsteady effects for the compressors tested in Part I. In addition, the effects of a whirling shaft were simulated to evaluate differences between a rotor with static offset and an actual whirling eccentric rotor. The models were also used to assess the influence of the nonaxisymmetric static pressure distribution on the rotor spool, which was not measured in the experiment. The models evaluated were (1) the two-sector parallel compressor (2SPC) model, (2) the infinite-segment-parallel-compressor (ISPC) model, and (3) the two-coupled actuator disk (2CAD) model. The results of these analyses were found to be in agreement with the experimental data in both sign and trend. Thus, the validated models provide a general means to predict the aerodynamic destabilizing forces for axial flow compressors in turbine engines. These tools have the potential to improve the design of rotordynamically stable turbomachinery.
    keyword(s): Force , Pressure , Flow (Dynamics) , Compressors , Clearances (Engineering) , Rotors , Axial flow , Blades , Whirls , Stators AND Unsteady flow ,
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      Unsteady Flow and Whirl-Inducing Forces in Axial-Flow Compressors: Part II—Analysis

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    http://yetl.yabesh.ir/yetl1/handle/yetl/126016
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    • Journal of Turbomachinery

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    contributor authorS. J. Song
    contributor authorD. C. Wisler
    contributor authorF. F. Ehrich
    contributor authorZ. S. Spakovszky
    contributor authorA. F. Storace
    contributor authorH.-W. Shin
    contributor authorM. Martinez-Sanchez
    contributor authorB. F. Beacher
    date accessioned2017-05-09T00:06:14Z
    date available2017-05-09T00:06:14Z
    date copyrightJuly, 2001
    date issued2001
    identifier issn0889-504X
    identifier otherJOTUEI-28689#446_1.pdf
    identifier urihttp://yetl.yabesh.ir/yetl/handle/yetl/126016
    description abstractAn experimental and theoretical investigation was conducted to evaluate the effects seen in axial-flow compressors when the centerline of the rotor becomes displaced from the centerline of the static structure of the engine, thus creating circumferentially nonuniform rotor-tip clearances. This displacement produces unsteady flow and creates a system of destabilizing forces, which contribute significantly to rotor whirl instability in turbomachinery. These forces were first identified by Thomas (1958. Bull. AIM, 71 , No. 11/12, pp. 1039–1063.) for turbines and by Alford (1965. J. Eng. Power, Oct., pp. 333–334) for jet engines. In Part I, the results from an experimental investigation of these phenomena were presented. In this Part II, three analytic models were used to predict both the magnitude and direction of the Thomas/Alford force in its normalized form, known as the β coefficient, and the unsteady effects for the compressors tested in Part I. In addition, the effects of a whirling shaft were simulated to evaluate differences between a rotor with static offset and an actual whirling eccentric rotor. The models were also used to assess the influence of the nonaxisymmetric static pressure distribution on the rotor spool, which was not measured in the experiment. The models evaluated were (1) the two-sector parallel compressor (2SPC) model, (2) the infinite-segment-parallel-compressor (ISPC) model, and (3) the two-coupled actuator disk (2CAD) model. The results of these analyses were found to be in agreement with the experimental data in both sign and trend. Thus, the validated models provide a general means to predict the aerodynamic destabilizing forces for axial flow compressors in turbine engines. These tools have the potential to improve the design of rotordynamically stable turbomachinery.
    publisherThe American Society of Mechanical Engineers (ASME)
    titleUnsteady Flow and Whirl-Inducing Forces in Axial-Flow Compressors: Part II—Analysis
    typeJournal Paper
    journal volume123
    journal issue3
    journal titleJournal of Turbomachinery
    identifier doi10.1115/1.1370165
    journal fristpage446
    journal lastpage452
    identifier eissn1528-8900
    keywordsForce
    keywordsPressure
    keywordsFlow (Dynamics)
    keywordsCompressors
    keywordsClearances (Engineering)
    keywordsRotors
    keywordsAxial flow
    keywordsBlades
    keywordsWhirls
    keywordsStators AND Unsteady flow
    treeJournal of Turbomachinery:;2001:;volume( 123 ):;issue: 003
    contenttypeFulltext
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    DSpace software copyright © 2002-2015  DuraSpace
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