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dc.contributor.authorCarroll, Brian Ren_US
dc.description.abstractRotors in fluid-film bearing supported turbomachinery are known to develop elliptical orbits as a result of rotor-bearing interactions, mass unbalance within the rotor, gravitational bending of the shaft and external excitation. In synchronous whirl, where the speed at which the shaft travels about the orbit is equal to the rotational speed of the rotor, temperature gradients may develop across the journal as a result of viscous shear in the bearingâ s lubricant film. This thermal gradient leads to bending of the shaft in a phenomenon known as The Morton Effect. Such thermally induced bending causes further growth of the elliptical orbit resulting in further bending leading to excessive vibration levels and premature bearing failure. This analysis examines the development of the Morton Effect in medium-speed turbochargers typical to shipboard propulsion engines and the effect that bearing clearance has on thermal stability. Floating ring and tilting pad journal bearings are considered with a single stage, overhung centrifugal compressor and an overhung axial turbine. Results indicate a correlation between bearing clearance and thermal stability in the rotor-bearing system. A model for the aerodynamic force generated as a result of interaction between air exiting a centrifugal compressor and the compressorâ s annulus in a turbocharger is then developed and applied to the rotor-bearing systems. Results suggest little correlation between this aerodynamic force and the development of the Morton Effect.en_US
dc.publisherVirginia Techen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectMorton Effecten_US
dc.titleSynchronous Thermal Instability Evaluation of Medium Speed Turbocharger Rotor-Bearing Systemsen_US
dc.contributor.departmentMechanical Engineeringen_US of Scienceen_US Polytechnic Institute and State Universityen_US
dc.contributor.committeechairKirk, R. Gordonen_US
dc.contributor.committeememberKasarda, Mary E. F.en_US
dc.contributor.committeememberKornhauser, Alan A.en_US

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