Analysis of Wakes Shed by Idealized Aircraft Engine Fan Blades for Noise Reduction

2004 ◽  
Author(s):  
Aurelien Borgoltz ◽  
Derek Geiger ◽  
William Devenport
Keyword(s):  
Noise Reduction ◽  
Aircraft Engine

Design and assessment of a distributed active acoustic liner concept for application to aircraft engine noise reduction

2017 ◽  
Vol 141 (5) ◽  
pp. 3643-3643
Author(s):  
Herve Lissek ◽  
Romain Boulandet ◽  
Sami Karkar ◽  
Gaël Matten ◽  
Manuel Collet ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Aircraft Engine ◽  
Engine Noise ◽  
Acoustic Liner

Fan noise reduction of an aircraft engine by inclining the outlet guide vanes

2015 ◽  
Vol 61 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Yu. D. Khaletskiy ◽  
Ya. S. Pochkin
Keyword(s):  
Noise Reduction ◽  
Aircraft Engine ◽  
Fan Noise ◽  
Guide Vanes

scholarly journals Estimation of Cumulative Noise Reduction at Certification Points for Supersonic Civil Aeroplane Using the Programmed Thrust Management at Take-off and Approach

2021 ◽  
Author(s):  
Mirzoyan Artur ◽  
Khaletskii Iurii
Keyword(s):  
Noise Reduction ◽  
Noise Level ◽  
Aircraft Engine ◽  
Automated System ◽  
Lapse Rate ◽  
Noise Sources ◽  
System Variable ◽  
Engine Control System ◽  
Power Setting ◽  
Main Engine

The reduction of the cumulative noise level at certification points applying to the supersonic civil aeroplane is estimated in the paper. The reduction is obtained by using an programmed thrust management with Programmed Lapse Rate based on the variation of engine power setting at take-off and approach. The use of proposed programmed reduced noise thrust management requires a change of the conventional noise certification procedures as well as further implementation as fully automated system (Variable Noise Reduction System) into aircraft/engine control system. The main engine noise sources such as the fan and exhaust jet are taken into account in the estimation. It is shown that the cumulative noise level using proposed programmed thrust management is lower by 10.7–12.2 EPNdB than using the conventional engine thrust control as currently applied to subsonic jet aeroplanes at take-off and approach.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

Satisfaction With Noise Reduction Circuits

1993 ◽  
Vol 2 (1) ◽  
pp. 51-53 ◽  
Author(s):  
Ruth A. Bentler
Keyword(s):  
Noise Reduction
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