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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Inlet distortion generation for a transonic compressor /

Papamarkos, Ioannis. January 2004 (has links) (PDF)
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, Sept. 2004. / Thesis Advisor(s): Raymond Shreeve. Includes bibliographical references (p. 53). Also available online.
2

Fourth order Multi-Time-Stepping Adams-Bashforth (MTSAB) scheme for NASA Glenn Research Center's Broadband Aeroacoustic Stator Simulation (BASS) Code

Allampalli, Vasanth. January 2010 (has links)
Dissertation (Ph.D.)--University of Toledo, 2010. / Typescript. "Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Engineering." "A dissertation entitled"--at head of title. Title from title page of PDF document. Bibliography: p. 152-156.
3

An application of modern control theory to a high bypass variable compressor geometry jet engine

Idelchik, Michael S January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Michael S. Idelchik. / M.S.
4

Physics based modeling of axial compressor stall

Zaki, Mina Adel. January 2009 (has links)
Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Dr. Lakshmi N. Sankar; Committee Member: Dr. Alex Stein; Committee Member: Dr. J.V. R. Prasad; Committee Member: Dr. Richard Gaeta; Committee Member: Dr. Suresh Menon. Part of the SMARTech Electronic Thesis and Dissertation Collection.
5

Physics based modeling of axial compressor stall

Zaki, Mina Adel 28 August 2009 (has links)
Axial compressors are used in a wide variety of aerodynamic applications and are one of the most important components in aero-engines. The operability of compressors is however limited at low-mass flow rates by fluid dynamic instabilities such as stall and surge. These instabilities can lead to engine failure and loss of engine power which can compromise the aircraft safety and reliability. Therefore, a better understanding of how stall occurs and the causes behind its inception is extremely important. In the vicinity of the stall line, the flow field is inherently unsteady due to the interactions between adjacent rows of blades, formation of separation cells, and the viscous effects including shock-boundary layer interaction. Accurate modeling of these phenomena requires a proper set of stable and accurate boundary conditions at the rotorstator interface that conserve mass, momentum and energy, while eliminating false reflections. As a part of this effort, an existing 3D Navier-Stokes analysis for modeling single stage compressors has been modified to model multi-stage axial compressors and turbines. Several rotor-stator interface boundary conditions have been implemented. These have been evaluated for the first stage (a stator and a rotor) of the two stage fuel turbine on the space shuttle main engine (SSME). Their effectiveness in conserving global properties such as mass, momentum, and energy across the interface, while yielding good performance predictions has been evaluated. While all the methods gave satisfactory results, a characteristic based approach and an unsteady sliding mesh approach are found to work best. Accurate modeling of the formation of stall cells requires the use of advanced turbulence models. As a part of this effort, a new advanced turbulence model called Hybrid RANS/KES (HRKES) has been developed and implemented. This model solves Menter's k--SST model near walls and switches to a Kinetic Eddy Simulation (KES) model away from walls. The KES model solves directly for local turbulent kinetic energy and local turbulent length scales, alleviating the grid spacing dependency of the length scales found in other Detached Eddy Simulation (DES) and Hybrid RANS/LES (HRLES) models. Within the HRKES model, combinations of two different blending functions have been evaluated for blending the near wall model to the KES model. The use of realizability constraints to bound the KES model parameters has also been studied for several internal and external flows. The current methodology is used in the prediction of the performance map for the NASA Stage 35 compressor configuration as a representative of a modern compressor stage. The present approach is found to satisfactory predict the onset of stall. It is found that the rotor blade tip leakage vortex and its interaction with the shock wave is mainly the reason behind the stall inception in this compressor stage.

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