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Showing papers on "Turbofan published in 2006"


Proceedings ArticleDOI
TL;DR: This paper proposes engine mechanical arrangements that can meet the cycle requirements and, when installed in an appropriate airframe, will be quiet relative to current turbofans.
Abstract: The Silent Aircraft Initiative is a research project funded by the Cambridge-MIT Institute aimed at reducing aircraft noise to the point where it is imperceptible in the urban environments around airports. The propulsion system being developed for this project has a thermodynamic cycle based on an ultrahigh bypass ratio turbofan combined with a variable area exhaust nozzle and an embedded installation. This cycle has been matched to the flight mission and thrust requirements of an all-lifting body airframe, and through precise scheduling of the variable exhaust nozzle, the engine operating conditions have been optimized for maximum thrust at top-of-climb, minimum fuel consumption during cruise, and minimum jet noise at low altitude. This paper proposes engine mechanical arrangements that can meet the cycle requirements and, when installed in an appropriate airframe, will be quiet relative to current turbofans. To reduce the engine weight, a system with a gearbox, or some other form of shaft speed reduction device, is proposed. This is combined with a low-speed fan and a turbine with high gap-chord spacing to further reduce turbomachinery source noise. An engine configuration with three fans driven by a single core is also presented, and this is expected to have further weight, fuel burn, and noise benefits.

155 citations


Patent
31 Oct 2006
TL;DR: In this paper, a turbofan engine assembly (10) including a core gas turbine engine (13), including a high-pressure compressor (14), a combustor (16), and a high pressure turbine (18), a low-pressure turbine (20), coupled to the core turbine engine, a counter-rotating booster compressor (22), and gearbox (100) including an input (110) and an output (111, 112), the gearbox output coupled to at least one of the first and second rotor sections.
Abstract: A turbofan engine assembly (10) including a core gas turbine engine (13) including a high-pressure compressor (14), a combustor (16), and a high-pressure turbine (18), a low-pressure turbine (20) coupled to the core gas turbine engine, a counter-rotating booster compressor (22) including a first rotor section (50) configured to rotate in a first direction and a second rotor section (60) configured to rotate in an opposite second direction, and a gearbox (100) including an input (110) and an output (111, 112), the gearbox output coupled to at least one of the first and second rotor sections, the gearbox input coupled to the low-pressure turbine.

128 citations


Patent
Alain Porte1
13 Sep 2006
TL;DR: In this paper, a turbofan provided with a pre-cooler is described, where the precooler was connected to a discharge pipe in the inner fairing of the aircraft.
Abstract: The invention concerns a turbofan provided with a pre-cooler. The invention is characterized in that to evacuate the heated cool air stream (24), at least one discharge pipe (25) is arranged in the chamber (12) and connects the pre-cooler (18) to at least one discharge orifice (26) provided in the inner fairing (10), in output of the exhaust nozzle (3) and at least more or less opposite the wing (16).

93 citations


Patent
23 Jan 2006
TL;DR: In this paper, an aircraft propulsion system which can secure the optimum thrust and thrust vector for flight conditions, as well as the optimum sectional area for the engine, and which is highly compatible with the environment is presented.
Abstract: To provide an aircraft propulsion system which can secure the optimum thrust and thrust vector for flight conditions, as well as the optimum sectional area for the engine, and which is highly compatible with the environment. An electrical generator is coupled to a turbofan engine, the electrical generator is driven by output power of the turbofan engine to output electric power, and an electromagnetic driving fan is driven by the electric power. On the other hand, after bringing each of coils in the electromagnetic driving fan to a superconductive state, liquid hydrogen is introduced to a heat exchanger, collects the energy of exhaust as heat, is then vaporized, and thereafter supplied to a combustor and to a fuel cell. Further, the electromagnetic driving fan is changed in its rotational phase by a rotating mechanism portion, is made movable in a width direction of a wing and a wing chord direction by a slide mechanism portion, and can be stored inside or outside the wing by a storage mechanism portion.

87 citations


Journal ArticleDOI
TL;DR: In this article, the authors report selected carbon species emission indices (EIs) for a Rolls Royce RB211-535-E4 turbofan engine that were acquired during the NASA EXPERiment to Characterize Aircraft Volatile Aerosol and Trace-species Emissions (EXCAVATE).

76 citations


Patent
24 Jul 2006
TL;DR: A translating cowl composed of two sub-structures forms the thrust reverser for a turbofan engine as discussed by the authors, which is used for direct or reverse thrust operation of the engine and access to the engine.
Abstract: A translating cowl composed of two sub-structures forms the thrust reverser for a turbofan engine. The two sub-structures form the rear part of a nacelle, are translatable, and have operative and inoperative modes of operation. The operative mode is used for direct or reverse thrust operation of the engine and the inoperative mode is used for access to the engine.

65 citations


Patent
25 Sep 2006
TL;DR: A turbofan gas turbine engine (10) as mentioned in this paper includes a forward fan section (33) with a row of fan rotor blades (32), a core engine (18), and a fan bypass duct (40) downstream of the forward fan and radially outwardly of the core engine.
Abstract: A turbofan gas turbine engine (10) includes a forward fan section (33) with a row of fan rotor blades (32), a core engine (18), and a fan bypass duct (40) downstream of the forward fan section (33) and radially outwardly of the core engine (18). The forward fan section (33) has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes (35) downstream of the forward fan rotor blades (32). An exemplary embodiment of the engine includes an afterburner (130) downstream of the fan bypass duct (40) between the core engine (18) and an exhaust nozzle (68). The variable fan outlet guide vanes (35) are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5 - 4+. Struts (31) extend radially across a radially inwardly curved portion (131) of a flowpath (29) of the engine (10) between the forward fan section (33) and the core engine (18).

52 citations


Journal ArticleDOI
TL;DR: In this paper, an axially segmented cavity liner is proposed to improve the attenuation of fan tones at high supersonic fan speeds, where the rotor-alone pressure field is well cut-on.

50 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of this acoustic scattering is examined by three-dimensional finite-element simulations of sound transmission in a turbofan inlet duct, and the results demonstrate how acoustic scattering by liner splices can adversely affect fan tone noise levels at low supersonic fan speeds, but have little adverse affect on noise level at high supersonIC fan speeds.

49 citations


Journal ArticleDOI
TL;DR: Fan flow deflection for jet noise reduction was applied to subscale nozzles simulating the geometry and exhaust conditions of separate-flow turbofan engines as mentioned in this paper, and two types of deflectors were tested, one comprising two pairs of vanes internal to the fan and the other consisting of a wedge positioned outside the fan duct.
Abstract: Fan flow deflection for jet noise reduction was applied to subscale nozzles simulating the geometry and exhaust conditions of separate-flow turbofan engines. Two types of deflectors were tested, one comprising two pairs of vanes internal to the fan duct and the other consisting of a wedge positioned outside the fan duct. The noise reduction achieved by the vanes was strong in the downward direction and moderate in the sideline direction. The wedge generated significant attenuation in both directions. The acoustic results are consistent with the measured distortion of the mean velocity field. An approach for the treatment ofnonaxisymmetricjets vis-a-vis perceived noise prediction is introduced.

41 citations


Patent
13 Nov 2006
TL;DR: In this article, a turbine engine emergency power system includes low and high pressure spools, the lower pressure spool including a low pressure compressor, coupled to a turbofan.
Abstract: A turbine engine emergency power system includes low and high pressure spools, the lower pressure spool including a low pressure compressor. A turbofan is coupled to the low pressure spool. The turbofan drives the low pressure spool in a windmill condition in which the low pressure turbine fails to provide rotational drive to the turbofan. A generator is rotationally driven by the low pressure spool in the windmill condition. A gear train is used to increase the speed of the generator in one example. In one example embodiment, a centrifugal clutch is used to selectively decouple the generator from the low pressure spool at a predetermined engine speed, which corresponds to normal operating speeds when the turbine engine is under power.

Journal ArticleDOI
TL;DR: In this article, the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, is transferred to an engine system analysis carried out at a lower level of resolution.
Abstract: Background . This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. This work will enable component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. Approach . The technique described in this paper utilizes an object-oriented, zero-dimensional (0D) gas turbine modeling and performance simulation system and a high-fidelity, three-dimensional (3D) computational fluid dynamics (CFD) component model. The work investigates relative changes in the simulated engine performance after coupling the 3D CFD component to the 0D engine analysis system. For the purposes of this preliminary investigation, the high-fidelity component communicates with the lower fidelity cycle via an iterative, semi-manual process for the determination of the correct operating point. This technique has the potential to become fully automated, can be applied to all engine components, and does not involve the generation of a component characteristic map. Results . This paper demonstrates the potentials of the “fully integrated” approach to component zooming by using a 3D CFD intake model of a high bypass ratio turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The high-fidelity model can fully define the characteristic of the intake at several operating condition and is subsequently used in the 0D cycle analysis to provide a more accurate, physics-based estimate of intake performance (i.e., pressure recovery) and hence, engine performance, replacing the default, empirical values. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the coupled, high-fidelity component is presented in this paper. The analysis carried out by this study demonstrates relative changes in the simulated engine performance larger than 1%. Conclusions . This investigation proves the value of the simulation strategy followed in this paper and completely justifies (i) the extra computational effort required for a more automatic link between the high-fidelity component and the 0D cycle, and (ii) the extra time and effort that is usually required to create and run a 3D CFD engine component, especially in those cases where more accurate, high-fidelity engine performance simulation is required.

Patent
06 Jun 2006
TL;DR: In this paper, the first stage rotor blades (58) in the low pressure turbine (24) are oriented opposite to the rotor blades(46,58) of the high and low pressure turbines (22,24) for counterrotation.
Abstract: A turbofan engine (10) includes a fan (14), compressor (18), combustor (20), single-stage high pressure turbine (22), and low pressure turbine (24) joined in serial flow communication. First stage rotor blades (58) in the low pressure turbine (24) are oriented oppositely to the rotor blades (46) in the high pressure turbine (22) for counterrotation. First stage stator vanes (52) in the low pressure turbine (24) have camber and twist for carrying swirl directly between the rotor blades (46,58) of the high and low pressure turbines (22,24).

Patent
06 Jun 2006
TL;DR: A turbofan engine includes a fan, compressor, combustor, high pressure turbine, and low pressure turbine joined in serial flow communication, and a transition duct includes fairings extending between platforms for channeling the combustion gases to the low-pressure turbine with corresponding swirl.
Abstract: A turbofan engine includes a fan, compressor, combustor, high pressure turbine, and low pressure turbine joined in serial flow communication. The high pressure turbine includes two stages of rotor blades to effect corresponding exit swirl in the combustion gases discharged therefrom. A transition duct includes fairings extending between platforms for channeling the combustion gases to the low pressure turbine with corresponding swirl. First stage rotor blades in the low pressure turbine are oriented oppositely to the rotor blades in the high pressure turbine for counterrotation.

Patent
06 Dec 2006
TL;DR: In this article, a system for transferring mechanical torque variably between a plurality of rotating machines in a turbofan engine was proposed, where a fixed gear ratio was obtained by coupling the relatively high and low-speed engine shafts to an epicyclic magnetic gearbox.
Abstract: A system for transferring mechanical torque variably between a plurality of rotating machines in a turbofan engine. Two devices are used, where the first device relies upon magnetic properties of a planetary magnetic gearbox to couple the magnetic machines. The second device is used to variably control the torque transfer between the magnetic machines. The system couples rotating shafts rotating at differing speeds within a turbofan engine for controllably transferring power. To transfer power in the system, a fixed gear ratio is obtained by coupling the relatively high- and low-speed engine shafts to an epicyclic magnetic gearbox.

Patent
21 Sep 2006
TL;DR: The thrust reverser as mentioned in this paper comprises a first reverser door and a second reversal door asymmetrically pivotable between a stowed position and a deployed position, one having a pivot axis closer to the central axis than the other.
Abstract: The thrust reverser comprises a first reverser door and a second reverser door asymmetrically pivotable between a stowed position and a deployed position, one having a pivot axis closer to the central axis than the other.

Patent
20 Jun 2006
TL;DR: A turbofan engine (10) includes a fan (18) driven by a core engine (22-28) and a surrounding fan nacelle (16) including a thrust reverser (36) and fan nozzle (46) disposed aft therefrom as discussed by the authors.
Abstract: A turbofan engine (10) includes a fan (18) driven by a core engine (22-28). A surrounding fan nacelle (16) includes a thrust reverser (36) and fan nozzle (46) disposed aft therefrom. A core cowl (20) surrounds the core engine and includes a core nozzle (42) extending aft therefrom. A row of poppet valves (56) extends through the core cowl (20) between the core nozzle (42) and fan nozzle (46) for selectively spoiling thrust from the core nozzle (42) when the reverser (36) is deployed.

Journal ArticleDOI
TL;DR: In this paper, the authors adapted the concept of a beveled nozzle for realistic engine geometries to reduce jet noise at takeoff, based on the characteristics of the noise sources in a dual-stream exhaust system, where the noise generation mechanisms of the inner shear layer were modified by beveling the primary nozzle to achieve noise reduction.
Abstract: Jet noise is a major component of total aircraft noise at takeoff, even for modern aircraft powered by high-bypass-ratio (BPR) turbofan engines with BPR of around five. The reduction of jet noise at fixed BPR has proven to be a formidable challenge, and no practical design that produces substantial aeroacoustic benefit has evolved despite significant effort. A simple concept of a beveled nozzle is adapted for realistic engine geometries. The strategy for noise reduction in the peak sector of noise radiation is based on our understanding of the characteristics of the noise sources in a dual-stream exhaust system. Specifically, the noise generation mechanisms of the inner shear layer are modified by beveling the primary nozzle to achieve noise reduction. Detailed aeroacoustic measurements are carried out statically and in the presence of a flight stream to assess the noise benefit of the modified exhaust system, relative to a conventional arrangement, at realistic engine cycle conditions. Two beveled nozzles of bevel angles 24 (bevel24) and 45 deg have been evaluated. The bevel24 nozzle has a low performance penalty (∼0.2%) at cruise power and produces substantial reduction in noise levels in the aft quadrant. The reduction in overall sound pressure levels is ∼5 to ∼7 dB near the spectral peak in the angular sector >110 deg. There is a slight increase (∼1 dB) in the overall sound pressure levels at the lower polar angles. The magnitude of noise reduction is strongly dependent on the velocity of the inner stream. The reduction in levels occurs over a wide frequency range; there is no increase at the higher frequencies, which is a typical trend for other noise reduction concepts. The effects of forward flight on the measured spectra are different at different azimuthal angles; further, the flight effects in the azimuthal plane are a function of the bevel angle. A total noise reduction of ∼4 dB effective perceived noise level is demonstrated at takeoff (sideline and overhead) at realistic flight Mach numbers with the bevel24 nozzle.

Patent
12 Oct 2006
TL;DR: In this paper, a turbofan engine control system is provided for managing a fan operating line, which may result in a stall or flutter condition, where the physical nozzle exit area is increased at the undesired stability condition in which the airflow into the engine creates a destabilizing pressure gradient at the inlet side of the turbo-fan.
Abstract: A turbofan engine control system is provided for managing a fan operating line. The engine (10) includes a spool having a turbine housed in a core nacelle (12). A turbofan (20) is coupled to the spool (14). A fan nacelle (34) surrounds the turbofan and core nacelle and provides a bypass flow path having a nozzle exit area (40). A controller (50) is programmed to effectively change the nozzle exit area in response to an undesired turbofan stability margin which may result in a stall or flutter condition. In one example, the physical nozzle exit area is increased at the undesired stability condition in which the airflow into the engine creates a destabilizing pressure gradient at the inlet side of the turbofan. A turbofan pressure ratio, turbofan pressure gradient, low spool speed and throttle position are monitored to determine the undesired turbofan stability margin.

Patent
12 Oct 2006
TL;DR: In this article, a turbofan emergency power system includes a controller that communicates with the flow control device to reduce the effective nozzle exit area (40) of the bypass flow path, which chokes the flow through the bypassflow path thereby increasing the rotational speed of the fan.
Abstract: A turbofan engine (10) employs a flow control device (41) that changes an effective exit nozzle area (40) associated with a bypass flow path (B) of the turbofan engine. A spool (14) couples a fan (20) to a generator (52). The turbofan emergency power system includes a controller (50) that communicates with the flow control device (41). Upon sensing an emergency condition, the controller manipulates the flow control device to reduce the effective nozzle exit area (40) of the bypass flow path, which chokes the flow through the bypass flow path thereby increasing the rotational speed of the fan. In this manner, the generator is driven at a higher rotational speed than if the flow through the bypass flow path was not choked, which enables a smaller generator to be utilized.

Journal ArticleDOI
TL;DR: In this paper, the authors present the performance-cycle analysis of a dual-spool, separate-exhaust turbofan engine with an interstage turbine burner (ITB) serving as a secondary combustor.
Abstract: This paper presents the performance-cycle analysis of a dual-spool, separate-exhaust turbofan engine, with an interstage turbine burner (ITB) serving as a secondary combustor. The ITB, which is located at the transition duct between the high- and the low-pressure turbines, is a relatively new concept for increasing specific thrust and lowering pollutant emissions in modern jet engine propulsion. A detailed performance analysis of this engine has been conducted for steady-state engine performance prediction. A code is written and is capable of predicting engine performances (i.e., thrust and thrust specific fuel consumption) at varying flight conditions and throttle settings. Two design-point engines were studied to reveal trends in performance at both full and partial throttle operations. A mission analysis is also presented to ensure the advantage of saving fuel by adding ITB.

Patent
12 Oct 2006
TL;DR: In this paper, a turbofan engine control system is provided for managing a low pressure compressor operating line and a controller is programmed to effectively change the nozzle exit area in response to an undesired low-pressure compressor stability margin which can result in a stall or surge condition.
Abstract: A turbofan engine control system is provided for managing a low pressure compressor operating line. The engine includes a low spool having a low pressure compressor housed in a core nacelle. A turbofan is coupled to the low spool. A fan nacelle surrounds the turbofan and core nacelle and provides a bypass flow path having a nozzle exit area. A controller is programmed to effectively change the nozzle exit area in response to an undesired low pressure compressor stability margin which can result in a stall or surge condition. In one example, the physical nozzle exit area is decreased at the undesired stability condition occurring during engine deceleration. A low pressure compressor pressure ratio, low spool speed and throttle position are monitored to determine the undesired stability margin.

Proceedings ArticleDOI
09 Jan 2006
TL;DR: In this paper, a parametric study of ice accretion on a high bypass turbofan engine booster rotor is presented, where both flow and droplets' governing equations are formulated and solved in the reference frame of the rotating blades.
Abstract: This paper presents a parametric study of ice accretion on a high bypass turbofan engine booster rotor. Both flow and droplets' governing equations are formulated and solved in the reference frame of the rotating blades. A Eulerian-Lagrangian approach is used for the continuous and discrete phases with one-way interaction model to simulate momentum and energy exchange on the droplets and their effects on the three-dimensional droplet trajectories. The flux-based collection efficiency is calculated for the rotor blade at 60%, 70%, 80%, 90% and 100% engine design speed. A quasi-3D analysis of the ice accretion over the rotor blade is conducted based on the computed flow characteristics using the code LEWICE. Results are presented for the ice shape variation along the span, inlet temperature and rotor speeds. The highest accumulation was predicted on the blade pressure side leading edge near the hub and increased with reduced rotor speed and flow temperature.

Patent
12 Oct 2006
TL;DR: In this paper, a flow control device is adapted to introduce a fluid into the bypass flow path for altering a boundary layer of a bypass flow that effectively changes the nozzle exit area.
Abstract: A turbofan engine includes core and fan nacelles that provide a bypass flow path having a nozzle exit area. The bypass flow path carries a bypass flow to be expelled from the nozzle exit area. A turbofan is arranged within the fan nacelle and upstream from the core nacelle for generating the bypass flow. A flow control device includes a surface in the bypass flow path including an aperture. The flow device is adapted to introduce a fluid into the bypass flow path for altering a boundary layer of the bypass flow that effectively changes the nozzle exit area. In one example, bleed air is introduced through the aperture. In another example, pulses of fluid from a Helmholz resonator flow through the aperture. By decreasing the boundary layer, the nozzle exit area is effectively increased. By increasing the boundary layer, the nozzle exit area is effectively decreased.

Proceedings ArticleDOI
01 Jun 2006
TL;DR: An experimental investigation using trailing edge blowing for reducing fan rotor/guide-vane wake interaction noise was completed in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel as mentioned in this paper, where data were acquired to measure noise, aerodynamic performance, and flow features for a 22" tip diameter fan representative of modern turbofan technology.
Abstract: An experimental investigation using trailing edge blowing for reducing fan rotor/guide vane wake interaction noise was completed in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel. Data were acquired to measure noise, aerodynamic performance, and flow features for a 22" tip diameter fan representative of modern turbofan technology. The fan was designed to use trailing edge blowing to reduce the fan blade wake momentum deficit. The test objective was to quantify noise reductions, measure impacts on fan aerodynamic performance, and document the flow field using hot-film anemometry. Measurements concentrated on approach, cutback, and takeoff rotational speeds as those are the primary conditions of acoustic interest. Data are presented for a 2% (relative to overall fan flow) trailing edge injection rate and show a 2 dB reduction in Overall Sound Power Level (OAPWL) at all fan test speeds. The reduction in broadband noise is nearly constant and is approximately 1.5 dB up to 20 kHz at all fan speeds. Measurements of tone noise show significant variation, as evidenced by reductions of up to 6 dB in the 2 BPF tone at 6700 rpm.: and increases of nearly 2 dB for the 4 BPF tone at approach speed. Aerodynamic performance measurements show the fan with 2 % injection has an overall efficiency that is comparable to the baseline fan and operates, as intended, with nearly the same pressure ratio and mass flow parameters. Hot-film measurements obtained at the approach operating condition indicate that mean blade wake filling in the tip region was not as significant as expected. This suggests that additional acoustic benefits could be realized if the trailing edge blowing could be modified to provide better filling of the wake momentum deficit. Nevertheless, the hot-film measurements indicate that the trailing edge blowing provided significant reductions in blade wake turbulence. Overall, these results indicate that further work may be required to fully understand the proper implementation of injecting flow at/near the trailing edge as a wake filling strategy. However, data do support the notion that noise reductions can be realized not only for tones but perhaps more importantly, also for broadband. Furthermore, the technique can be implemented without adversely effecting overall fan aerodynamic performance.

Patent
12 Oct 2006
Abstract: A turbofan engine (10) is provided that includes a spool (14). The spool (14) supports a turbine (18) and is housed within a core nacelle (12). A fan (20) is coupled to the spool (14) and includes a target operability line. The target operability line provides desired fuel consumption, engine performance, and/or fan operability margin. A fan nacelle (34) surrounds the fan (20) and core nacelle (12) to provide a bypass flow path (39) having a nozzle exit area (40). A controller (50) is programmed to command a flow control device (41) for changing the nozzle exit area (40). The change in nozzle exit area (40) achieves the target operability line in response to an engine operating condition that is a function of airspeed and throttle position. A change in the nozzle exit area (40) is used to move the operating line toward a fan stall or flutter boundary by manipulating the fan pressure ratio.

Patent
12 Oct 2006
TL;DR: In this paper, a variable area nozzle (FVAN) is used to selectively vector the fan bypass flow by adjusting each of the multiple aerodynamical Iy shaped inserts relative to other inserts, providing an asymmetrical fan nozzle exit area.
Abstract: A turbofan engine (10) includes a fan variable area nozzle (FVAN) (50) which effectively changes the physical area and geometry within a fan bypass flow path (40) to manipulate the pressure ratio of the bypass flow. The FVAN generally includes a multitude of aerodynamical Iy shaped inserts (52) circumf erentially located about the core nacelle (12). The FVAN at a fully stowed position (takeoff /landing) takes up a minimum of area within the fan bypass flow path to effectively maximize the fan nozzle exit area (44) while in the fully deployed position (cruise) takes up a maximum of area within the bypass flow path to effectively minimize the fan nozzle exit area. By separately adjusting each of the multiple of inserts relative the other inserts the FVAN provides an asymmetrical fan nozzle exit area to selectively vector the fan bypass flow.

Patent
12 Oct 2006
TL;DR: In this paper, a turbofan engine includes a fan variable area nozzle, which includes a louver system having a multiple of slats generally transverse to the engine axis.
Abstract: A turbofan engine includes a fan variable area nozzle, which includes a louver system having a multiple of slats generally transverse to the engine axis. Each of the louver slats are pivotally mounted to the fan nacelle to vary the effective area of the fan nozzle exit area and permit efficient engine operation at predefined pressure ratios.

Patent
12 Oct 2006
TL;DR: In this article, a gas turbine engine system includes a fan bypass passage (27), a core nacelle (28), having an inner fixed structure (40) within the bypass passage, a passage (42) extending through the inner fixed structures, and a duct nozzle (48), which is selectively moveable to influence the variable cross-sectional exit area.
Abstract: A gas turbine engine system includes a fan bypass passage (27), a core nacelle (28) having an inner fixed structure (40) within the fan bypass passage, a passage (42) extending through the inner fixed structure, and a duct nozzle (48). The passage includes an inlet (44) for receiving a fan airflow (F2) from the fan bypass passage and an outlet (46) for discharging the fan airflow. The duct nozzle includes a variable cross-sectional exit area (50) for controlling the fan airflow within the passage and is selectively moveable to influence the variable cross-sectional exit area.

Patent
07 Jun 2006
TL;DR: In this paper, a turbofan gas turbine propulsion engine includes a system to transfer power from the low pressure turbine (128) to the high pressure turbine(126) and/or extract additional load from the lower-pressure turbine(128) during certain turbine operational conditions.
Abstract: A turbofan gas turbine propulsion engine includes a system to transfer power from the low pressure turbine (128) to the high pressure turbine (126) and/or extract additional load from the low pressure turbine (128) during certain turbofan engine operational conditions. The systems include a hydrostatic power transfer system that includes a hydraulic pump (154) and a hydraulic motor (156) coupled to the low pressure and high pressure turbine (126), respectively. The systems additionally include a mechanical and electrical load shifting/loading sharing systems that use clutches and gear assemblies to share and/or shift load between the turbines