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Turbofan

About: Turbofan is a research topic. Over the lifetime, 4114 publications have been published within this topic receiving 39490 citations. The topic is also known as: fanjet & turbofan engine.


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01 Jun 2010
TL;DR: In this article, an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations is presented. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3-D unsteady, full wheel CRP CFD computations and aero-acoustic simulations.
Abstract: Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3-D unsteady, full wheel CRP CFD computations and aero-acoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full wheel unsteady 3-D RANS simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method were extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in the literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was re-designed for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the re-designed CRP demonstrated an average reduction of 7.25 dB in mean SPL computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the re-designed CRP demonstrated a reduction of 9.2 EPNdB and 8.6 EPNdB at the FAR 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.Copyright © 2010 by ASME

23 citations

Journal ArticleDOI
TL;DR: The contribution of this work lies in the combination of linear system control and nonlinear system control methods to design an effective controller for the turbofan engine and to provide a new way for turb ofan engine control research.

23 citations

01 Aug 1985
TL;DR: The Flight Propulsion System (FPS) as discussed by the authors is the engine designed to achieve Energy Efficient Engine (E3) goals, which required aerodynamic, mechanical and system technologies advanced beyond that of current production engines.
Abstract: The Energy Efficient Engine (E3) is a NASA program to create fuel saving technology for future transport engines. The Flight Propulsion System (FPS) is the engine designed to achieve E3 goals. Achieving these goals required aerodynamic, mechanical and system technologies advanced beyond that of current production engines. These technologies were successfully demonstrated in component rigs, a core engine and a turbofan ground test engine. The design and benefits of the FPS are presented. All goals for efficiency, environmental considerations, and economic payoff were met. The FPS has, at maximum cruise, 10.67 km (35,000 ft), M0.8, standard day, a 16.9 percent lower installed specific fuel consumption than a CF6-50C. It provides an 8.6 percent reduction in direct operating cost for a short haul domestic transport and a 16.2 percent reduction for an international long distance transport.

23 citations

Patent
17 Feb 1989
TL;DR: In this paper, a movable air deflector is proposed to deflect air passing through the cold flow air duct of a turbofan engine in a direction such that it approximates the theoretical air flow line and does not enter a cavity defined by the interior of the thrust reverser door when the door is in its closed position.
Abstract: The present invention provides a movable air deflector which, in a first position, deflects air passing through the cold flow air duct of a turbofan engine in a direction such that it approximates the theoretical air flow line and does not enter a cavity defined by the interior of the thrust reverser door when the door is in its closed position. A linkage mechanism connects the air deflector to the door actuator, such that, when the door is moved to its opened or thrust reversing position, the deflector is moved to a second position so as to minimize its interference with the thrust reversing air flow.

23 citations

Proceedings ArticleDOI
13 Jan 2014
TL;DR: Results indicate that the methods developed may be used to both generate and characterize complex distortion profiles at the aerodynamic interface plane, providing new information about airframe/engine integration.
Abstract: There is a present need for simulating and measuring the inlet swirl distortion generated by airframe/engine system interactions to identify potential degradation in fan performance and operability in a full-scale, ground testing environment. Efforts are described to address this need by developing and characterizing methods for complex, prescribed distortion patterns. A relevent inlet swirl distortion profile was generated by a novel new method, dubbed the StreamVane method, and measured in a small scale tunnel using stereoscopic particle image velocimetry (PIV) as a precursor for swirl distortion generation and characterization in an operating turbofan research engine. The StreamVane prototype tested was made of ABS plastic using additive manufacturing and was used to generate swirl distortion patterns that mimick boundary layer ingesting engine inlets with a pair of tightly wound vortices and swirl angle magnitudes up to 15°. Diagnostic development efforts for distortion measurements within the research engine paralleled the StreamVane characterization. The system used for research engine PIV measurements is described along with data obtained in the wake of a total pressure distortion screen for engine conditions at idle and 80% corrected fan speed engine power settings. Data reduction algorithms are put forth to reduce spurious velocity vectors and uncertainty estimations specific to the inlet distortion test rig are made. Results indicate that the methods developed may be used to both generate and characterize complex distortion profiles at the aerodynamic interface plane, providing new information about airframe/engine integration.

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023163
2022320
2021112
2020131
2019175
2018189