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A Novel Approach for Reducing Rotor Tip-Clearance Induced Noise in Turbofan EnginesRotor tip-clearance induced noise, both in the form of rotor self noise and rotor-stator interaction noise , constitutes a significant component of total fan noise. Innovative yet cost effective techniques to suppress rotor-generated noise are, therefore, of foremost importance for improving the noise signature of turbofan engines. To that end, the feasibility of a passive porous treatment strategy to positively modify the tip-clearance flow field is addressed. The present study is focused on accurate viscous flow calculations of the baseline and the treated rotor flow fields. Detailed comparison between the computed baseline solution and experimental measurements shows excellent agreement. Tip-vortex structure, trajectory, strength, and other relevant aerodynamic quantities are extracted from the computed database. Extensive comparison between the untreated and treated tip-clearance flow fields is performed. The effectiveness of the porous treatment for altering the rotor-tip vortex flow field in general and reducing the intensity of the tip vortex, in particular, is demonstrated. In addition, the simulated flow field for the treated tip clearly shows that substantial reduction in the intensity of both the shear layer roll-up and boundary layer separation on the wall is achieved.
Document ID
20010050993
Acquisition Source
Langley Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Khorrami, Mehdi R.
(High Technology Corp. Hampton, VA United States)
Li, Fei
(High Technology Corp. Hampton, VA United States)
Choudhari, Meelan
(NASA Langley Research Center Hampton, VA United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2001
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
AIAA Paper 2001-2148
Meeting Information
Meeting: 7th AIAA/CEAS Aeroacoustics Conference
Location: Maastricht
Country: Netherlands
Start Date: May 28, 2001
End Date: May 30, 2001
Sponsors: Confederation of European Aerospace Societies, American Inst. of Aeronautics and Astronautics
Distribution Limits
Public
Copyright
Public Use Permitted.
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