Open-Rotor Aerodynamics Installation Effects By a RANS-Lifting Line Coupling Method

2014 ◽  
Author(s):  
Martin Barry
Keyword(s):  
Coupling Method ◽  
Rotor Aerodynamics ◽  
Installation Effects ◽  
Open Rotor ◽  
Line Coupling ◽  
Lifting Line

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.

scholarly journals The Influence of an Upstream Pylon on Open Rotor Aerodynamics at Angle of Attack

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Nishad G. Sohoni ◽  
Cesare A. Hall ◽  
Anthony B. Parry
Keyword(s):  
Potential Field ◽  
Angle Of Attack ◽  
Separated Flow ◽  
Rotor Blades ◽  
Tip Vortex ◽  
Rotor Wake ◽  
Rotor Aerodynamics ◽  
Open Rotor ◽  
Urans Cfd ◽  
Work Done

The aerodynamic impact of installing a horizontal pylon in front of a contra-rotating open rotor engine, at take-off, was studied. The unsteady interactions of the pylon's wake and potential field with the rotor blades were predicted by full-annulus URANS CFD calculations at 0 deg and 12 deg angle of attack (AoA). Two pylon configurations were studied: one where the front rotor blades move down behind the pylon (DBP), and one where they move up behind the pylon (UBP). When operating at 12 deg AoA, the UBP orientation was shown to reduce the rear rotor tip vortex sizes and separated flow regions, whereas the front rotor wake and vortex sizes were increased. In contrast, the DBP orientation was found to reduce the incidence variations onto the front rotor, leading to smaller wakes and vortices. The engine flow was also time-averaged, and the variation in work done on average midspan streamlines was shown to depend strongly on variation in incidence, along with a smaller contribution related to change of radius.

A Method for Predicting Contra Rotating Propellers Off-Design Performance

2014 ◽  
Author(s):  
Matthieu Dubosc ◽  
Nicolas Tantot ◽  
Philippe Beaumier ◽  
Grégory Delattre
Keyword(s):  
Design Tool ◽  
Preliminary Design ◽  
Detailed Design ◽  
One Dimensional ◽  
Open Rotor ◽  
Line Theory ◽  
Lifting Line ◽  
Lifting Line Theory ◽  
Complex Methods ◽  
Engine Cycle

This article presents a method for predicting contra rotating propellers individual and total performance which is fast and robust enough to be used in performance engine cycle and engine subsystems detailed design. The method is based on the use of single propeller maps and models mutual induced velocities thanks to one-dimensional theories. These velocities are responsible for interferences between propellers. This article goes through the assumptions on which stands the proposed method and shows that it is relevant compared against more complex methods such as lifting line theory and definitively provides a valuable easy-to-enforce preliminary design tool for open rotor propulsor controls sizing.

Ultrasonic Flaw Detection for High Impedance Materials Using a Transmission Line Coupling Method

1997 ◽  
Vol 36 (Part 1, No. 5B) ◽  
pp. 3287-3289 ◽  
Author(s):  
Hirokuni Yamaguchi ◽  
Masasumi Yoshizawa ◽  
Norio Tagawa ◽  
Tadashi Moriya ◽  
Shin-ichi Yagi
Keyword(s):  
Transmission Line ◽  
Flaw Detection ◽  
Coupling Method ◽  
Ultrasonic Flaw Detection ◽  
High Impedance ◽  
Ultrasonic Flaw ◽  
Line Coupling

scholarly journals How to improve open rotor aerodynamics at cruise and take-off

2014 ◽  
Vol 118 (1208) ◽  
pp. 1103-1123 ◽  
Author(s):  
C. Hall ◽  
A. Zachariadis ◽  
T. Brandvik ◽  
N. Sohoni
Keyword(s):  
Three Dimensional ◽  
Noise Emission ◽  
Rotor Aerodynamics ◽  
Rotor Design ◽  
Design Changes ◽  
Flow Features ◽  
Open Rotor ◽  
Speed Up ◽  
The Impact ◽  
High Thrust

Abstract A key challenge in open rotor design is getting the optimum aerodynamics at both the cruise and take-off conditions. This is particularly difficult because the operation and the requirements of an open rotor are very different at cruise compared to takeoff. This paper uses CFD results to explore the impact of various design changes on the cruise and take-off flow-fields. The paper then considers how a given open rotor design is best operated at take-off to minimise noise whilst maintaining high thrust. The main findings are that various design modifications can be applied to control the flow features that lead to lost efficiency at cruise and increased noise emission at take-off. A breakdown of the lost power terms from CFD solutions demonstrates how developments in open rotor design have led to reduced aerodynamic losses. At take-off, the operating point of the open rotor should be set such that the non-dimensional lift is as high as possible, without causing significant flow separation. This can be achieved through suitable amounts of re-pitch and speed up applied to a design. Comparisons with fully three-dimensional CFD show that the amount of re-pitch required can be determined using simplified methods such as two-dimensional CFD and a Blade Element Method.

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