2026-09-19T11:52:03Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/516582022-01-13T07:54:11Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022

Choon S. Tan, John J. Adamczyk, Edward M. Greitzer and Mark Drela.. Nolan, Sean Patrick Rock Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Massachusetts Institute of Technology. Department of Aeronautics and Astronautics 2010-02-09T16:57:42Z 2010-02-09T16:57:42Z 2009 2009 http://hdl.handle.net/1721.1/51658 501813945 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009. Includes bibliographical references (leaves 89-92). The effect of the upstream wake phase on the work input (i.e., rise in stagnation enthalpy across the blade row) of a transonic rotor is examined computationally and analytically. It is found that the compressor work depends on the path followed by the wake vortices as they travel through the rotor passage. There can be an important impact on time-mean performance when the time-dependent circulation of the shed vortices in the wake is phase-locked to the rotor position. For the configurations tested, the calculated change in time-mean work input was approximately three percent. The effect on work input is explained in terms of the influence of the time-mean relative stagnation pressure nonuniformity associated with the unsteady (but phase-locked) wake vortex flow field. Changes in vortex path mean that the position of this nonuniformity is altered relative to the rotor. There is lower pressure rise, and thus lower work, when the rotor blade is embedded in the region of low time-mean relative stagnation pressure than when it is immersed in a region of high relative stagnation pressure. In addition to this essentially two-dimensional effect, it is demonstrated that the locations of the wake vortex paths can have substantial effect on the tip clearance flow, implying potential impact on pressure rise capability and rotor stability limits. Model calculations are given to show the magnitude and nature of this phenomenon. by Sean Patrick Rock Nolan. Ph.D. 100 p. eng Massachusetts Institute of Technology M.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. http://dspace.mit.edu/handle/1721.1/7582 Aeronautics and Astronautics. Effects of upstream wake phasing on the performance of transonic compressors Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="4b1247e1-7e86-4361-ae04-936651353944"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Effects of upstream wake phasing on the performance of transonic compressors</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2009</PublicationDate> <Authors> <Author> <DisplayName>Nolan, Sean Patrick Rock</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Aeronautics and Astronautics.</Keyword> <Abstract>The effect of the upstream wake phase on the work input (i.e., rise in stagnation enthalpy across the blade row) of a transonic rotor is examined computationally and analytically. It is found that the compressor work depends on the path followed by the wake vortices as they travel through the rotor passage. There can be an important impact on time-mean performance when the time-dependent circulation of the shed vortices in the wake is phase-locked to the rotor position. For the configurations tested, the calculated change in time-mean work input was approximately three percent. The effect on work input is explained in terms of the influence of the time-mean relative stagnation pressure nonuniformity associated with the unsteady (but phase-locked) wake vortex flow field. Changes in vortex path mean that the position of this nonuniformity is altered relative to the rotor. There is lower pressure rise, and thus lower work, when the rotor blade is embedded in the region of low time-mean relative stagnation pressure than when it is immersed in a region of high relative stagnation pressure. In addition to this essentially two-dimensional effect, it is demonstrated that the locations of the wake vortex paths can have substantial effect on the tip clearance flow, implying potential impact on pressure rise capability and rotor stability limits. Model calculations are given to show the magnitude and nature of this phenomenon.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>