Experimental Validation of an Active Stator Technology Reducing Modern Turbofan Engine Noise

2007 ◽  
Author(s):  
Nadine Genoulaz ◽  
Jacques Julliard ◽  
Eric Bouty ◽  
Rudolf Maier ◽  
Joergen Zillmann ◽  
...  
Keyword(s):  
Experimental Validation ◽  
Engine Noise ◽  
Turbofan Engine

Development, Analysis, and Validation of a Simultaneous Inlet Total Pressure and Swirl Distortion Generator

2020 ◽  
Author(s):  
Dustin J. Frohnapfel ◽  
K. Todd Lowe ◽  
Walter F. O’Brien
Keyword(s):  
Total Pressure ◽  
Experimental Validation ◽  
Computational Analysis ◽  
Pressure Recovery ◽  
Turbofan Engine ◽  
Full Field ◽  
Inlet Distortion ◽  
Swirl Angle ◽  
Total Pressure Recovery ◽  
Ground Test

Abstract Over the last decade, the Turbomachinery and Propulsion Research Laboratory at Virginia Tech has researched, invented, developed, computationally analyzed, experimentally tested, and improved turbofan engine inlet distortion generators. This effort began with modernizing and improving inlet total pressure distortion screens originally conceived over half a century ago; continued with the invention of inlet swirl distortion generators (StreamVanes™) made possible only through advances in modern additive manufacturing technology; and has, thus far, culminated in a novel combined device (ScreenVanes™) capable of simulating realistic flight conditions of coupled inlet total pressure and swirl distortion in a ground-test turbofan engine research platform. The present research focuses on the methodology development, computational analysis, and experimental validation of a novel simultaneous inlet total pressure and swirl distortion generator. A case study involving a single bend S-duct inlet distortion profile demonstrates the ability to generate a high-fidelity profile simulation, yet outlines a design process sufficiently generic for application to any arbitrary inlet geometry or distortion profile. A computational fluid dynamics simulation of the S-duct inlet provided the target profile extracted at the aerodynamic interface plane. Next, utilizing a method of inverse propagation, the planar distortion profile was propagated upstream to yield a flow field that could be manufactured by a distortion generator adequately isolated from turbomachinery effects. The total pressure distortion screen and swirl distortion StreamVane components were then designed and computationally analyzed. Upon successful computational reproduction of the S-duct inlet distortion profile, experimental hardware was fabricated and tested to validate the ScreenVane methodology and distortion generating device. Comparison of the S-duct manufactured distortion and the ScreenVane manufactured distortion was used as the primary criterion for profile replication success. Results from a computational analysis of both the S-duct and ScreenVane indicated excellent agreement in distortion pattern shape, extent, and intensity with full-field total pressure recovery and swirl angle profiles matching within approximately 0.80% and 2.6°, respectively. Furthermore, experimental validation of the ScreenVane indicated nearly identical full-field total pressure recovery and swirl angle profile replication of approximately 1.10% and 2.6°, respectively, when compared to the computational results. The investigation concluded that not only was the ScreenVane device capable of accurately simulating a complex inlet distortion profile, but also produced a viable device for full-scale turbofan engine ground test.

Turbofan-engine noise suppression.

1968 ◽  
Vol 5 (3) ◽  
pp. 215-220 ◽  
Author(s):  
ROBERT E. PENDLEY ◽  
ALAN H. MARSH
Keyword(s):  
Noise Suppression ◽  
Engine Noise ◽  
Turbofan Engine

Comparison of Measured Low-Frequency Engine Noise With Combustion and Jet Noise Predictions for a Turbofan Engine With an Internal Lobed Mixer Nozzle

2007 ◽  
Author(s):  
Lysbeth S. Lieber ◽  
Donald S. Weir
Keyword(s):  
Low Frequency ◽  
Jet Noise ◽  
Combustion Noise ◽  
Noise Model ◽  
Engine Noise ◽  
Turbofan Engine ◽  
Technology Program ◽  
Modeling Techniques ◽  
Noise Data ◽  
Static Conditions

This paper presents an examination of the low-frequency engine noise of a turbofan engine with an internal lobed mixer nozzle, and identifies the contributions of the combustion and exhaust jet component noise sources within the low frequency portion of the spectrum by applying recently developed modeling techniques. This investigation was performed as part of the NASA Quiet Aircraft Technology Program. Because the mixer reduces the total jet noise, the combustion noise source becomes a significant contributor. In addition, the character of the jet noise for the mixer nozzle is different from that for a single-stream or coannular nozzle. Although the internal mixer reduces the low-frequency shear-induced jet noise, it also produces an additional higher frequency contribution to the jet noise due to enhanced turbulence levels produced by the mixing process. Therefore, the modeling techniques that predict the low-frequency component source noise must capture sufficient physics of the noise generation process for the combustor and mixer nozzle to accurately represent the component spectral distributions. The improved modeling of component source noise for both combustor and jet sources was addressed as part of the NASA Quiet Aircraft Technology Program. This activity included development of a new narrowband combustion noise model, as well as the application of a recent jet noise model for nozzles with internal forced mixers. The noise data used in this study was taken during the NASA Engine Validation of Noise Reduction Concepts (EVNRC) Program. Both static and flight noise measurements were made at a range of power settings using the Honeywell TFE731-60 turbofan engine. The engine configuration of interest for this study employed a nozzle with an internal lobed mixer. Comparison of static and flight data with predictions from the combustion and jet noise models indicates that combustor noise has a significant contribution to lower-frequency engine noise (in the 400–1000 Hz range), particularly for flight conditions, where the jet noise is reduced due to flight effects, and also for lower power settings at static conditions. However, further calibration of the combustion and jet noise prediction techniques will be required, with isolated component noise data, before these models may be applied with certainty to model total engine noise in the low-frequency range.

Active control of engine noise transmitted into cavities: simulation, experimental validation and sound quality assessment

2008 ◽  
Vol 123 (5) ◽  
pp. 3872-3872
Author(s):  
Leopoldo P. De Oliveira ◽  
Paul Sas ◽  
Wim Desmet ◽  
Karl Janssens ◽  
Peter Gajdatsy ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Active Control ◽  
Experimental Validation ◽  
Sound Quality ◽  
Engine Noise

scholarly journals Turbine Noise: Its Significance in the Civil Aircraft Noise Problem

1969 ◽  
Author(s):  
M. J. T. Smith ◽  
K. W. Bushell
Keyword(s):  
Aircraft Noise ◽  
Full Scale ◽  
Engine Noise ◽  
Turbofan Engine ◽  
Significant Contributor ◽  
Civil Aircraft ◽  
Available Information

The authors show the presence of noise from the turbine of a turbojet or turbofan engine to be a significant contributor the overall engine noise. They review currently available information from both full-scale engines and model turbines and correlate it along lines following those previously developed for fans and compressors.

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