Multipoint Aerodynamic Design of Ultrashort Nacelles for Ultrahigh-Bypass-Ratio Engines

Performance and aerodynamic aspects of ultra-high bypass ratio ducted engines have been investigated with an emphasis on nozzle aerodynamics. The interference with aircraft aerodynamics could not be covered. Numerical methods were used for aerodynamic investigations of geometrically different aft end configurations for bypass ratios between 12 and 18, this is the optimum range for long missions which will be important for future civil engine applications. Results are presented for a wide range of operating conditions and effects on engine performance are discussed. The limitations for higher bypass ratios than 12 to 18 do not come from nozzle aerodynamics but from installation effects. It is shown that using CFD and performance calculations an improved aerodynamic design can be achieved. Based on existing correlations, for thrust and mass-flow, or using aerodynamic tailoring by CFD and including performance investigations, it is possible to increase the thrust coefficient up to 1%.

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METHOD OF OPTIMAL AERODYNAMIC DESIGN OF THE NACELLE FOR THE MAIN PROPULSION SYSTEM WITH A HIGH BYPASS RATIO

TsAGI Science Journal ◽

10.1615/tsagiscij.v46.i6.30 ◽

2015 ◽

Vol 46 (6) ◽

pp. 533-558 ◽

Cited By ~ 6

Author(s):

Nikolay Alekseevich Zlenko ◽

Sergey Vladimirovich Mikhaylov ◽

Andrey Aleksandrovich Savelyev ◽

Andrey Vladimirovich Shenkin

Keyword(s):

Propulsion System ◽

Aerodynamic Design ◽

Bypass Ratio

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Numerical Investigations of a Tip Turbine Aerodynamic Design in a Propulsion System for VTOL Vehicles

Energies ◽

10.3390/en12153003 ◽

2019 ◽

Vol 12 (15) ◽

pp. 3003

Author(s):

Xin Xiang ◽

Guoping Huang ◽

Jie Chen ◽

Lei Li ◽

Weiyu Lu

Keyword(s):

Three Dimensional ◽

Propulsion System ◽

Navier Stokes ◽

Energy Extraction ◽

Aerodynamic Design ◽

High Reaction ◽

Computational Fluid Dynamics Cfd ◽

Cfd Method ◽

High Thrust ◽

Bypass Ratio

High thrust and low specific fuel consumption (SFC) are important for vertical takeoff and landing (VTOL) vehicles. An effective way to decrease the SFC is to increase the bypass ratio (BPR) of the propulsion system. The air-driven fan (or fan-in-wing) has a very high bypass ratio and has proved to be successful in VTOL aircrafts. However, the tip turbine that extracts energy for the air-driven fan faces the low-solidity problem and performs inadequately. In this study, we developed a high-reaction method for the aerodynamic design of a tip turbine to solve the low-solidity problem. A typical tip turbine was selected and designed by both conventional and high-reaction methods. Three-dimensional flow fields were numerically simulated through a Reynolds-averaged Navier-Stokes (RANS)-based computational fluid dynamics (CFD) method. The energy extraction rate was proposed to evaluate and display the energy extraction capability of the turbine. The results showed that the high-reaction turbine could solve the low-solidity problem and significantly increase the isentropic efficiency from approximately 80.0% to 85.6% and improve the isentropic work by 71.9% compared with the conventional method (from 10.28 kW/kg to 17.67 kW/kg).

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Noise Considerations in High Bypass Ratio Fan Engine Design

ASME 1970 Winter Annual Meeting: GT Papers ◽

10.1115/70-wa/gt-14 ◽

1970 ◽

Cited By ~ 1

Author(s):

A. O. Kohn

Keyword(s):

Technical Problem ◽

Aircraft Engine ◽

Scale Model ◽

Aerodynamic Design ◽

General Electric Company ◽

Electric Company ◽

Engine Design ◽

Acoustic Treatment ◽

Work Done ◽

Bypass Ratio

The General Electric Company is engaged in a number of programs to reduce aircraft-engine noise, ranging from the reheat turbojet for the SST to high bypass ratio lift fans for V/STOL applications. Many of these programs are government-sponsored and have been described elsewhere. The major company-sponsored program is development of the reduced-noise CF6 engine, a design undertaken to achieve a noise level significantly below that of current engines. Analysis and experimental work — done on scale model and engine fans to arrive at the best tradeoff between weight, performance, and noise — resulted in a aerodynamic design that, coupled with development of efficient acoustic treatment of the ducts, has yielded an engine measuring 10 PNdB quieter than current operational engines. The author details three specific technical problem areas (acoustic treatment, turbine noise, and modulation tones) and their impact on CF6 noise.

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