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Acoustic and Laser Doppler Anemometer Results for Confluent, 22-Lobed, and Unique-Lobed Mixer Exhaust Systems for Subsonic Jet Noise ReductionThe objective of this task was to develop a design methodology and noise reduction concepts for high bypass exhaust systems which could be applied to both existing production and new advanced engine designs. Special emphasis was given to engine cycles with bypass ratios in the range of 4:1 to 7:1, where jet mixing noise was a primary noise source at full power takeoff conditions. The goal of this effort was to develop the design methodology for mixed-flow exhaust systems and other novel noise reduction concepts that would yield 3 EPNdB noise reduction relative to 1992 baseline technology. Two multi-lobed mixers, a 22-lobed axisymmetric and a 21-lobed with a unique lobe, were designed. These mixers along with a confluent mixer were tested with several fan nozzles of different lengths with and without acoustic treatment in GEAE's Cell 41 under the current subtask (Subtask C). In addition to the acoustic and LDA tests for the model mixer exhaust systems, a semi-empirical noise prediction method for mixer exhaust system is developed. Effort was also made to implement flowfield data for noise prediction by utilizing MGB code. In general, this study established an aero and acoustic diagnostic database to calibrate and refine current aero and acoustic prediction tools.
Document ID
20020081325
Acquisition Source
Glenn Research Center
Document Type
Contractor Report (CR)
Authors
Salikuddin, M. (General Electric Aircraft Engines Cincinnati, OH United States)
Martens, S. (General Electric Aircraft Engines Cincinnati, OH United States)
Shin, H. (General Electric Aircraft Engines Cincinnati, OH United States)
Majjigi, R. K. (General Electric Aircraft Engines Cincinnati, OH United States)
Krejsa, Gene
Date Acquired
September 7, 2013
Publication Date
September 1, 2002
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
NAS 1.26:211598
NASA/CR-2002-211598
E-13385
Funding Number(s)
PROJECT: RTOP 781-30-12
CONTRACT_GRANT: NAS3-26617
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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