Reduction of Unsteady Stator-Rotor Interaction by Trailing Edge Blowing Using MEMS Based Microvalves

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dc.contributor.authorRao, Nikhil M.en
dc.contributor.committeechairNg, Wing Faien
dc.contributor.committeememberBurdisso, Ricardo A.en
dc.contributor.committeememberDancey, Clinton L.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T20:34:05Zen
dc.date.adate1999-04-30en
dc.date.available2014-03-14T20:34:05Zen
dc.date.issued1999-04-16en
dc.date.rdate2000-04-30en
dc.date.sdate1999-04-23en
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 minimizes 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
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-042399-125728en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-042399-125728/en
dc.identifier.urihttp://hdl.handle.net/10919/31854en
dc.publisherVirginia Techen
dc.relation.haspartetd.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectTrailing Edge Blowingen
dc.subjectNoiseen
dc.subjectAeroacousticsen
dc.subjectTurbomachineryen
dc.subjectMEMS.en
dc.titleReduction of Unsteady Stator-Rotor Interaction by Trailing Edge Blowing Using MEMS Based Microvalvesen
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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