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dc.contributor.authorRao, Nikhil M.en_US
dc.date.accessioned2014-03-14T20:34:05Z
dc.date.available2014-03-14T20:34:05Z
dc.date.issued1999-04-16en_US
dc.identifier.otheretd-042399-125728en_US
dc.identifier.urihttp://hdl.handle.net/10919/31854
dc.description.abstractThis research performs an experimental study of a trailing edge blowing system that can adapt to variations in flow parameters and reduce the unsteady stator-rotor interaction at all engine operating conditions. The fan rotor of a 1/14 scale turbofan propulsion simulator is subjected to spatially periodic, circumferential inlet flow distortions. The distortions are generated by four struts that support a centerbody in the inlet mounted onto the simulator. To reduce the unsteady effects of the strut wakes on the rotor blades, the wake is re-energized by injecting mass from the trailing edge of the strut. Each strut is provided with discrete blowing holes that open out through the strut trailing edge. Each blowing hole is connected to a MEMS based microvalve, which controls the blowing rate of the hole. The microvalve is actuated by a signal voltage, generated by a PID controller that accepts free stream and wake axial flow velocities as inputs and minimzes their difference. To quantify the effectiveness of trailing edge blowing the far-field noise is measured in an anechoic chamber. The experiments are performed for two simulator test speeds, 29,500 rpm and 40,000 rpm, with and without trailing edge blowing. The maximum reduction recorded at 29,500 rpm is 8.2 dB, and at 40,000 rpm is 7.3 dB. Reductions of 2.9 dB and greater are observed at the first five harmonics of the blade passing frequency. The sound power level at the blade passing frequency, calculated from measured far-field directivity, is reduced by 4.4 dB at 29,500 rpm and by 2.9 dB at 40,000 rpm. The feasibility and advantage of active control is demonstrated by the ability of the system to respond to a step change in the inlet flow velocity, and achieve optimum wake filling in approximately 8 seconds.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartetd.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectTrailing Edge Blowingen_US
dc.subjectNoiseen_US
dc.subjectAeroacousticsen_US
dc.subjectTurbomachineryen_US
dc.subjectMEMS.en_US
dc.titleReduction of Unsteady Stator-Rotor Interaction by Trailing Edge Blowing Using MEMS Based Microvalvesen_US
dc.typeThesisen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineMechanical Engineeringen_US
dc.contributor.committeechairNg, Wing Faien_US
dc.contributor.committeememberBurdisso, Ricardo A.en_US
dc.contributor.committeememberDancey, Clinton L.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-042399-125728/en_US
dc.date.sdate1999-04-23en_US
dc.date.rdate2000-04-30
dc.date.adate1999-04-30en_US


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