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dc.contributor.advisorChoon S. Tan.en_US
dc.contributor.authorGordon, Kenneth A. (Kenneth Andrew), 1970-en_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.en_US
dc.date.accessioned2005-08-23T18:06:32Z
dc.date.available2005-08-23T18:06:32Z
dc.date.issued1999en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/8183
dc.descriptionThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1999.en_US
dc.description"June 1999."en_US
dc.descriptionIncludes bibliographical references (p. 383-388).en_US
dc.description.abstractThe effects of two types of flow nonuniformity on stall inception behavior were assessed with linearized stability analyses of two compressor flow models. Response to rotating tip clearance asymmetries induced by a whirling rotor shaft or rotor height variations were investigated with a two-dimensional flow model. A 3-D compressor model was also developed to study the stability of both full-span and part-span rotating stall modes in annular geometries with radial flow variations. The studies focussed on (1) understanding what compressor designs were sensitive to these types of circumferential and spanwise flow nonuniformities, and (2) situations where 2-D stability theories were inadequate because of 3-D flow effects. Rotating tip clearance nonuniformities caused the greatest performance loss for shafts whirling at the rotating stall frequency. A whirling shaft displacement of 1% chord caused the stalling mass flow to rise by as much as 10% and the peak pressure rise to decrease by 6%. These changes were an order of magnitude larger than for equivalent-sized stationary or rotor-locked clearance asymmetries. Spanwise flow nonuniformities always destabilized the compressor, so that 2-D models over-predicted the stall margin compared to 3-D theory. The difference increased for compressors with larger spanwise variations of characteristic slope and reduced characteristic curvature near the peak. Differences between 2-D and 3-D stall point predictions were generally unacceptable (2-4% of flow coefficient) for single-stage configurations, but were less than 1% for multistage compressors. 2-D analyses predicted the wrong stall mode for specific cases of radial inlet flow distortion, mismatching and annulus area contraction, where higher-order radial modes led to stall.en_US
dc.description.abstract(cont.) The stability behavior of flows with circumferential or radial nonuniformity was unified through a single stability criterion. The stall point for both cases was set by the integral around the annulus of the pressure rise characteristic slope, weighted by the amplitude of the mode shape. For the case of steady circumferential variations, this criterion reduced to the integrated mean slope (IMS) condition associated with steady inlet distortions. The rotating tip clearance asymmetry model was also used to demonstrate the feasibility of actively controlling the shaft position to suppress rotating stall. In axisymmetric mean flow, this method only stabilized the first harmonic mode, increasing the operating range until surge or higher harmonic modes became unstable.en_US
dc.description.statementofresponsibilityby Kenneth A. Gordon.en_US
dc.format.extent388 p.en_US
dc.format.extent23779486 bytes
dc.format.extent23779245 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectAeronautics and Astronautics.en_US
dc.titleThree-dimensional rotating stall inception and effects of rotating tip clearance asymmetry in axial compressorsen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.en_US
dc.identifier.oclc50047655en_US


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