Publication:
Near-stall modal disturbances within a transonic compressor rotor

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Authors
Londono, Andrea.
Subjects
Transonic
Compressor
Pressure Instability
Low Dominant Frequencies
Turbomachinery
Near Stall Disturbances
Advisors
Gannon, Anthony J.
Hobson, Garth V.
Date of Issue
2011-12
Date
December 2011
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
This research effort seeks to better understand non-periodic flow characteristics for a forward swept axial transonic compressor rotor when operating near stall. Improved performance of a military gas turbine engine may be achieved by better understanding the mechanisms responsible for near-stall non-periodic disturbances within a transonic compressor rotor. Using pressure transducers, embedded within the rotor wall casing, data were acquired and calibrated at various speeds up to 90% of maximum rotation velocity. Within the 90% design speed, various data sets were acquired for different throttle configurations. A new method to post-process the data to allow better investigating of the non-periodic flow characteristics was developed. Using Fast Fourier Transforms, two distinct and dominant frequencies were identified and analyzed. Contour pressure distribution maps for varying throttle configurations; and the amplitude differences for each frequency of interest was generated to illustrate correlations in frequency strength and its relationship with tip-leakage vortices, normal/oblique shocks, and passage-to-passage interactions. This study uses effective instrumentation and robust data reduction techniques to successfully identify passage-to-passage distribution of non-periodic and periodic low dominant frequencies within the rotor blade passage prior to stall.
Type
Description
Series/Report No
Department
Mechanical and Aerospace Engineering (MAE)
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
xvi, 135 p. : ill. (chiefly col.) ; 28 cm.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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