Topic
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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Papers
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16 Jun 2015
TL;DR: An exemplary gas turbine engine includes a fan bypass duct (120) defined between a fan nacelle (102) and core cowl of an engine core (104), including a cooled cooling air system (110) configured to receive cooling air from a primary flowpath bleed (132) at a diffuser within the engine core.
Abstract: An exemplary gas turbine engine includes a fan bypass duct (120) defined between a fan nacelle (102) and core cowl of an engine core (104). The engine core (104) includes a cooled cooling air system (110) configured to receive cooling air from a primary flowpath bleed (132) at a diffuser within the engine core (104) and configured to provide cooled cooling air to at least one component within the engine core (104). The cooled cooling air system (110) including an air-air heat exchanger (130).
29 citations
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08 Apr 2013TL;DR: In this paper, a conceptual structural analysis and optimization tool was used for a conceptual loads analysis and structural weights estimate of an open rotor hybrid wing body aircraft (HWB) for community noise analysis.
Abstract: Through a recent NASA contract, Boeing Research and Technology in Huntington Beach, CA developed and optimized a conceptual design of an open rotor hybrid wing body aircraft (HWB). Open rotor engines offer a significant potential for fuel burn savings over turbofan engines, while the HWB configuration potentially allows to offset noise penalties through possible engine shielding. Researchers at NASA Langley converted the Boeing design to a FLOPS model which will be used to develop take-off and landing trajectories for community noise analyses. The FLOPS model was calibrated using Boeing data and shows good agreement with the original Boeing design. To complement Boeing s detailed aerodynamics and propulsion airframe integration work, a newly developed and validated conceptual structural analysis and optimization tool was used for a conceptual loads analysis and structural weights estimate. Structural optimization and weight calculation are based on a Nastran finite element model of the primary HWB structure, featuring centerbody, mid section, outboard wing, and aft body. Results for flight loads, deformations, wing weight, and centerbody weight are presented and compared to Boeing and FLOPS analyses.
29 citations
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17 Jun 2002
TL;DR: The aerodynamic performance of an isolated fan or rotor alone model was measured in the NASA Glenn Research Center 9- by 15-foot Low Speed Wind Tunnel as part of the Fan Broadband Source Diagnostic Test conducted at NASA Glenn as discussed by the authors.
Abstract: The aerodynamic performance of an isolated fan or rotor alone model was measured in the NASA Glenn Research Center 9- by 15- Foot Low Speed Wind Tunnel as part of the Fan Broadband Source Diagnostic Test conducted at NASA Glenn. The Source Diagnostic Test was conducted to identify the noise sources within a wind tunnel scale model of a turbofan engine and quantify their contribution to the overall system noise level. The fan was part of a 1/5th scale model representation of the bypass stage of a current technology turbofan engine. For the rotor alone testing, the fan and nacelle, including the inlet, external cowl, and fixed area fan exit nozzle, were modeled in the test hardware; the internal outlet guide vanes located behind the fan were removed. Without the outlet guide vanes, the velocity at the nozzle exit changes significantly, thereby affecting the fan performance. As part of the investigation, variations in the fan nozzle area were tested in order to match as closely as possible the rotor alone performance with the fan performance obtained with the outlet guide vanes installed. The fan operating performance was determined using fixed pressure/temperature combination rakes and the corrected weight flow. The performance results indicate that a suitable nozzle exit was achieved to be able to closely match the rotor alone and fan/outlet guide vane configuration performance on the sea level operating line. A small shift in the slope of the sea level operating line was measured, which resulted in a slightly higher rotor alone fan pressure ratio at take-off conditions, matched fan performance at cutback conditions, and a slightly lower rotor alone fan pressure ratio at approach conditions. However, the small differences in fan performance at all fan conditions were considered too small to affect the fan acoustic performance.
29 citations
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16 Nov 2007TL;DR: In this paper, a pivoting arrangement for a thrust reverser door of a gas turbine engine is described, the pivot fitting having a base and a shaft projecting from a main side of the base.
Abstract: A pivot arrangement for a thrust reverser door of a gas turbine engine, the pivot fitting having a base and a shaft projecting from a main side of the base. The shaft receives a preferably curved pivot arm of the door to provide a low profile arrangement which improves performance when the doors are stowed.
29 citations
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TL;DR: In this paper, the relative amplitude and phase relationships between core pressures at various locations and between the core pressures and far field acoustic pressure were determined by using correlation and coherence techniques, which is consistent with a simplified model using fluctuating entropy as a source term.
Abstract: Fluctuating pressure measurements at several locations within the core of a turbofan engine were made simultaneously with far field acoustic measurements. Correlation and coherence techniques were used to determine the relative amplitude and phase relationships between core pressures at these various locations and between the core pressures and far field acoustic pressure. The combustor is a low frequency source region for acoustic propagation through the core nozzle and out to the far field. The relation between source pressure and the resulting sound pressure involves a 180 degree phase shift and an amplitude transfer function which varies approximately as frequency squared. This is consistent with a simplified model using fluctuating entropy as a source term.
29 citations