Installation Effects on Contra-Rotating Open Rotor Noise at High-Speed

2014 ◽  
Author(s):  
Yann Colin ◽  
Fabien Wlassow ◽  
Bastien Caruelle ◽  
Thomas Node-Langlois ◽  
Magdi Omais ◽  
...  
Keyword(s):  
High Speed ◽  
Installation Effects ◽  
Rotor Noise ◽  
Open Rotor

Advanced open rotor noise prediction

2014 ◽  
Vol 118 (1208) ◽  
pp. 1125-1135 ◽  
Author(s):  
M. J. Kingan
Keyword(s):  
High Speed ◽  
Broadband Noise ◽  
Current Status ◽  
Prediction Methods ◽  
Noise Prediction ◽  
Acoustic Data ◽  
Rotor Noise ◽  
Future Challenges ◽  
Open Rotor ◽  
Development And Validation

Abstract The purpose of this paper is to describe the current status of open rotor noise prediction methods and to highlight future challenges in this area. A number of analytic and numerical methods are described which can be used for predicting ‘isolated’ and ‘installed’ open rotor tonal noise. Broadband noise prediction methods are also described and it is noted that further development and validation of the current models is required. The paper concludes with a discussion of the analytical methods which are used to assess the acoustic data collected during the high-speed wind-tunnel testing of a model scale advanced open rotor rig.

Installation Effects on Contra-Rotating Open Rotor Noise

2010 ◽  
Author(s):  
Julien Ricouard ◽  
Emmanuel Julliard ◽  
Magdi Omais ◽  
Vincent Regnier ◽  
Anthony Parry ◽  
...  
Keyword(s):  
Installation Effects ◽  
Rotor Noise ◽  
Open Rotor

scholarly journals Reverse Thrust Aerodynamics of Variable Pitch Fans

2018 ◽  
Author(s):  
Tim S. Williams ◽  
Cesare A. Hall
Keyword(s):  
High Speed ◽  
Pressure Ratio ◽  
Test Case ◽  
Suction Surface ◽  
Flow Angle ◽  
Variable Pitch ◽  
Open Rotor ◽  
Weight Penalty ◽  
Reverse Thrust ◽  
Rotor Loss

Variable pitch fans are of interest for future low pressure ratio fan systems since they provide improved operability relative to fixed pitch fans. If they can also be re-pitched such that they generate sufficient reverse thrust they could eliminate the engine drag and weight penalty associated with bypass duct thrust reversers. This paper sets out to understand the details of the 3D fan stage flow field in reverse thrust operation. The study uses the Advanced Ducted Propulsor variable pitch fan test case, which has a design fan pressure ratio of 1.29. Comparison with spanwise probe measurements show that the computational approach is valid for examining the variation of loss and work in the rotor in forward thrust. The method is then extended to a reverse thrust configuration using an extended domain and appropriate boundary conditions. Computations, run at two rotor stagger settings, show that the spanwise variation in relative flow angle onto the rotor aligns poorly to the rotor inlet metal angle. This leads to two dominant rotor loss sources: one at the tip associated with positive incidence, and the second caused by negative incidence at lower span fractions. The second loss is reduced by opening the rotor stagger setting, and the first increases with rotor suction surface Mach number. The higher mass flow at more open rotor settings provide higher gross thrust, up to 49% of the forward take-off value, but is limited by the increased loss at high speed.

scholarly journals Limitations of Phased Array Beamforming in Open Rotor Noise Source Imaging

AIAA Journal ◽  
2014 ◽  
Vol 52 (8) ◽  
pp. 1810-1817 ◽  
Author(s):  
Csaba Horváth ◽  
Edmane Envia ◽  
Gary G. Podboy
Keyword(s):  
Phased Array ◽  
Noise Source ◽  
Source Imaging ◽  
Rotor Noise ◽  
Open Rotor ◽  
Array Beamforming

Development and Application of a Multi-Disciplinary Multi-Regime Design Methodology of a Low-Noise Contra-Rotating Open-Rotor

2015 ◽  
Author(s):  
Michaël Leborgne ◽  
Timothée Lonfils ◽  
Ingrid Lepot
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Design Methodology ◽  
Design Procedure ◽  
Low Noise ◽  
Design Parameters ◽  
Mechanical Constraints ◽  
Open Rotor ◽  
Mechanical Optimization ◽  
Lifting Line

This paper focuses on the development and exploitation of a multi-disciplinary, optimization-assisted, design methodology for contra-rotating open-rotors. The design procedure relies on a two-step approach. An aero-mechanical optimization is first performed to generate a geometry with good performances over several high-speed points representative of a mission. This geometry is subsequently used as the baseline of an aero-mechanical-acoustic optimization focusing on interaction noise reduction at Cutback and Sideline low-speed points. In terms of design parameters, both rotors are modified for the first phase but only the upper part of the front rotor is altered for the noise minimization. A fully-automatic high-fidelity aero-mechanical-acoustic computational chain with fluid-structure coupling is exploited in combination with evolutionary algorithms assisted by surrogate models for the constrained-optimization process. The acoustic footprint is estimated by a simplified but fast and relevant formulation combining an unsteady lifting-line and an acoustic propagation method. The best geometry of the first design gains 1.2pt in weighted efficiency while respecting all the aero-mechanical constraints. The acoustic optimization shows that noise reduction at Sideline and Cutback points is strongly antagonistic. However, significant Sideline noise reduction from 3.5 to 5.5dB depending on the harmonics is achieved while maintaining Cutback noise and without major degradation of high-speed efficiency.

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