Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D17/00—Regulating or controlling by varying flow
  • F01D17/10—Final actuators
  • F01D17/12—Final actuators arranged in stator parts
  • F01D17/14—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits
  • F01D17/16—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of nozzle vanes
  • F01D17/162—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of nozzle vanes for axial flow, i.e. the vanes turning around axes which are essentially perpendicular to the rotor centre line
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/40—Casings; Connections of working fluid
  • F04D29/52—Casings; Connections of working fluid for axial pumps
  • F04D29/54—Fluid-guiding means, e.g. diffusers
  • F04D29/56—Fluid-guiding means, e.g. diffusers adjustable
  • F04D29/563—Fluid-guiding means, e.g. diffusers adjustable specially adapted for elastic fluid pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D17/00—Regulating or controlling by varying flow
  • F01D17/10—Final actuators
  • F01D17/12—Final actuators arranged in stator parts
  • F01D17/14—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
  • F02K1/06—Varying effective area of jet pipe or nozzle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K3/00—Plants including a gas turbine driving a compressor or a ducted fan
  • F02K3/02—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber
  • F02K3/04—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type
  • F02K3/06—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type with front fan
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2220/00—Application
  • F05D2220/30—Application in turbines
  • F05D2220/36—Application in turbines specially adapted for the fan of turbofan engines

Definitions

• the present invention relates to a gas turbine engine, and more particularly to a turbofan engine having a variable geometry fan exit guide vane (FEGV) system to change a fan bypass flow path area thereof.
• FEGV variable geometry fan exit guide vane
• Conventional gas turbine engines generally include a fan section and a core section with the fan section having a larger diameter than that of the core section.
• the fan section and the core section are disposed about a longitudinal axis and are enclosed within an engine nacelle assembly.
• Combustion gases are discharged from the core section through a core exhaust nozzle while an annular fan bypass flow, disposed radially outward of the primary core exhaust path, is discharged along a fan bypass flow path and through an annular fan exhaust nozzle.
• a majority of thrust is produced by the bypass flow while the remainder is provided from the combustion gases.
• the fan bypass flow path is a compromise suitable for take-off and landing conditions as well as for cruise conditions.
• a minimum area along the fan bypass flow path determines the maximum mass flow of air.
• insufficient flow area along the bypass flow path may result in significant flow spillage and associated drag.
• the fan nacelle diameter is typically sized to minimize drag during these engine-out conditions which results in a fan nacelle diameter that is larger than necessary at normal cruise conditions with less than optimal drag during portions of an aircraft mission.
• a gas turbine engine includes a core nacelle defined about an engine centerline axis, a fan nacelle mounted at least partially around the core nacelle to define a fan bypass flow path for a fan bypass airflow, a fan variable area nozzle axially movable relative the fan nacelle to vary a fan nozzle exit area and adjust a pressure ratio of the fan bypass airflow during engine operation, and a gear system driven by a core engine within the core nacelle to drive a fan within the fan nacelle, the gear system defines a gear reduction ratio of greater than or equal to about 2.3.
• the engine may further include a multiple of fan exit guide vanes in communication with the fan bypass flow path, the multiple of fan exit guide vane rotatable about an axis of rotation to vary the fan bypass flow path. Additionally or alternatively, the multiple of fan exit guide vanes may be simultaneously rotatable. Additionally or alternatively, the multiple of fan exit guide vanes may be mounted within an intermediate engine case structure.
• each of the multiple of fan exit guide vanes may include a pivotable portion rotatable about the axis of rotation relative a fixed portion. Additionally or alternatively, the pivotable portion may include a leading edge flap.
• the controller may be operable to control the fan variable area nozzle to vary a fan nozzle exit area and adjust the pressure ratio of the fan bypass airflow. Additionally or alternatively, the controller may be operable to reduce the fan nozzle exit area at a cruise flight condition. Additionally or alternatively, the controller may be operable to control the fan nozzle exit area to reduce a fan instability.
• the fan variable area nozzle may define a trailing edge of the fan nacelle.
• the gear system may define a gear reduction ratio of greater than or equal to about 2.5. Additionally or alternatively, the gear system may define a gear reduction ratio of greater than or equal to 2.5.
• the core engine may include a low pressure turbine which defines a pressure ratio that is greater than about five (5).
• the core engine may include a low pressure turbine which defines a pressure ratio that is greater than five (5).
• the bypass flow may define a bypass ratio greater than about six (6). Additionally or alternatively, the bypass flow may define a bypass ratio greater than about ten (10). Additionally or alternatively, the bypass flow may define a bypass ratio greater than ten (10).
• the engine may further comprise a multiple of fan exit guide vanes in communication with the fan bypass flow path, the multiple of fan exit guide vanes rotatable about an axis of rotation to vary the fan bypass flow path.
• Figure 1A is a general schematic partial fragmentary view of an exemplary gas turbine engine embodiment for use with the present invention
• Figure IB is a perspective side partial fragmentary view of a FEGV system which provides a fan variable area nozzle
• Figure 2A is a sectional view of a single FEGV airfoil;
• Figure 2B is a sectional view of the FEGV illustrated in Figure 2A shown in a first position;
• Figure 2C is a sectional view of the FEGV illustrated in Figure 2A shown in a rotated position
• Figure 3A is a sectional view of another embodiment of a single FEGV airfoil
• Figures 3B is a sectional view of the FEGV illustrated in Figure 3A shown in a first position
• Figure 3C is a sectional view of the FEGV illustrated in Figure 3A shown in a rotated position
• Figure 4A is a sectional view of another embodiment of a single FEGV slatted airfoil with a ;
• Figures 4B is a sectional view of the FEGV illustrated in Figure 4A shown in a first position
• Figure 4C is a sectional view of the FEGV illustrated in Figure 4A shown in a rotated position.
• Figure 1 illustrates a general partial fragmentary schematic view of a gas turbofan engine 10 suspended from an engine pylon P within an engine nacelle assembly N as is typical of an aircraft designed for subsonic operation.
• the turbofan engine 10 includes a core section within a core nacelle 12 that houses a low spool 14 and high spool 24.
• the low spool 14 includes a low pressure compressor 16 and low pressure turbine 18.
• the low spool 14 drives a fan section 20 directly or through a gear train 22.
• the high spool 24 includes a high pressure compressor 26 and high pressure turbine 28.
• a combustor 30 is arranged between the high pressure compressor 26 and high pressure turbine 28.
• the low and high spools 14, 24 rotate about an engine axis of rotation A.
• the engine 10 is a high-bypass geared architecture aircraft engine.
• the engine 10 bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10)
• the gear train 22 is an epicyclic gear train such as a planetary gear system or other gear system with a gear reduction ratio of greater than about 2.3
• the low pressure turbine 18 has a pressure ratio that is greater than about five (5).
• the engine 10 in the disclosed embodiment is a high-bypass geared turbofan aircraft engine in which the engine 10 bypass ratio is greater than ten (10), the turbofan diameter is significantly larger than that of the low pressure compressor 16, and the low pressure turbine 18 has a pressure ratio greater than five (5).
• Low pressure turbine 18 pressure ratio is pressure measured prior to inlet of low pressure turbine 18 as related to the pressure at the outlet of the low pressure turbine 18 prior to exhaust nozzle.
• the gear train 22 may be an epicycle gear train such as a planetary gear system or other gear system with a gear reduction ratio of greater than about 2.5. It should be understood, however, that the above parameters are exemplary of only one geared turbofan engine and that the present invention is likewise applicable to other gas turbine engines including direct drive turbofans.
• the fan section 20 communicates airflow into the core nacelle 12 for compression by the low pressure compressor 16 and the high pressure compressor 26. Core airflow compressed by the low pressure compressor 16 and the high pressure compressor 26 is mixed with the fuel in the combustor 30 then expanded over the high pressure turbine 28 and low pressure turbine 18.
• the turbines 28, 18 are coupled for rotation with respective spools 24, 14 to rotationally drive the compressors 26, 16 and, through the gear train 22, the fan section 20 in response to the expansion.
• a core engine exhaust E exits the core nacelle 12 through a core nozzle 43 defined between the core nacelle 12 and a tail cone 32.
• a bypass flow path 40 is defined between the core nacelle 12 and the fan nacelle 34.
• the engine 10 generates a high bypass flow arrangement with a bypass ratio in which approximately 80 percent of the airflow entering the fan nacelle 34 becomes bypass flow B.
• the bypass flow B communicates through the generally annular bypass flow path 40 and may be discharged from the engine 10 through a fan variable area nozzle (FVAN) 42 which defines a variable fan nozzle exit area 44 between the fan nacelle 34 and the core nacelle 12 at an aft segment 34S of the fan nacelle 34 downstream of the fan section 20.
• FVAN fan variable area nozzle
• the core nacelle 12 is generally supported upon a core engine case structure 46.
• a fan case structure 48 is defined about the core engine case structure 46 to support the fan nacelle 34.
• the core engine case structure 46 is secured to the fan case 48 through a multiple of circumferentially spaced radially extending fan exit guide vanes (FEGV) 50.
• FEGV fan exit guide vanes
• the fan case structure 48, the core engine case structure 46, and the multiple of circumferentially spaced radially extending fan exit guide vanes 50 which extend therebetween is typically a complete unit often referred to as an intermediate case. It should be understood that the fan exit guide vanes 50 may be of various forms.
• the intermediate case structure in the disclosed embodiment includes a variable geometry fan exit guide vane (FEGV) system 36.
• Thrust is a function of density, velocity, and area. One or more of these parameters can be manipulated to vary the amount and direction of thrust provided by the bypass flow B. A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio.
• the fan section 20 of the engine 10 is nominally designed for a particular flight condition - - typically cruise at about 0.8 Mach and about 35,000 feet.
• the flight condition of 0.8 Mach and 35,000 ft, with the engine at its best fuel consumption - also known as "bucket cruise Thrust Specific Fuel Consumption ('TSFC')" - is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point.
• Low fan pressure ratio is the pressure ratio across the fan blade alone, without the fan exit guide vane (FEGV) system 36.
• the low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45.
• Low corrected fan tip speed is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tambient deg R) / 518.7) ⁇ 0.5].
• the "Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft / second.
• the FEGV system 36 and/or the FVAN 42 is operated to adjust fan bypass air flow such that the angle of attack or incidence of the fan blades is maintained close to the design incidence for efficient engine operation at other flight conditions, such as landing and takeoff.
• the FEGV system 36 and/or the FVAN 42 may be adjusted to selectively adjust the pressure ratio of the bypass flow B in response to a controller C. For example, increased mass flow during windmill or engine-out, and spoiling thrust at landing.
• the FEGV system 36 will facilitate and in some instances replace the FVAN 42, such as, for example, variable flow area is utilized to manage and optimize the fan operating lines which provides operability margin and allows the fan to be operated near peak efficiency which enables a low fan pressure-ratio and low fan tip speed design; and the variable area reduces noise by improving fan blade aerodynamics by varying blade incidence.
• the FEGV system 36 thereby provides optimized engine operation over a range of flight conditions with respect to performance and other operational parameters such as noise levels.
• each fan exit guide vane 50 includes a respective airfoil portion 52 defined by an outer airfoil wall surface 54 between the leading edge 56 and a trailing edge 58.
• the outer airfoil wall 54 typically has a generally concave shaped portion forming a pressure side and a generally convex shaped portion forming a suction side. It should be understood that respective airfoil portion 52 defined by the outer airfoil wall surface 54 may be generally equivalent or separately tailored to optimize flow characteristics.
• Each fan exit guide vane 50 is mounted about a vane longitudinal axis of rotation 60.
• the vane axis of rotation 60 is typically transverse to the engine axis A, or at an angle to engine axis A.
• various support struts 61 or other such members may be located through the airfoil portion 52 to provide fixed support structure between the core engine case structure 46 and the fan case structure 48.
• the axis of rotation 60 may be located about the geometric center of gravity (CG) of the airfoil cross section.
• An actuator system 62 illustrated schematically; Figure 1A
• a unison ring operates to rotate each fan exit guide vane 50 to selectively vary the fan nozzle throat area ( Figure 2B).
• the unison ring may be located, for example, in the intermediate case structure such as within either or both of the core engine case structure 46 or the fan case 48 ( Figure 1A).
• the FEGV system 36 communicates with the controller C to rotate the fan exit guide vanes 50 and effectively vary the fan nozzle exit area 44.
• Other control systems including an engine controller or an aircraft flight control system may also be usable with the present invention.
• Rotation of the fan exit guide vanes 50 between a nominal position and a rotated position selectively changes the fan bypass flow path 40. That is, both the throat area (Figure 2B) and the projected area (Figure 2C) are varied through adjustment of the fan exit guide vanes 50.
• bypass flow B is increased for particular flight conditions such as during an engine-out condition.
• engine bypass flow may be selectively vectored to provide, for example only, trim balance, thrust controlled maneuvering, enhanced ground operations and short field performance.
• FIG. 3A another embodiment of the FEGV system 36' includes a multiple of fan exit guide vane 50' which each includes a fixed airfoil portion 66F and pivoting airfoil portion 66P which pivots relative to the fixed airfoil portion 66F.
• the pivoting airfoil portion 66P may include a leading edge flap which is actuatable by an actuator system 62' as described above to vary both the throat area (Figure 3B) and the projected area (Figure 3C).
• FIG. 4A another embodiment of the FEGV system 36" includes a multiple of slotted fan exit guide vane 50" which each includes a fixed airfoil portion 68F and pivoting and sliding airfoil portion 68P which pivots and slides relative to the fixed airfoil portion 68F to create a slot 70 vary both the throat area (Figure 4B) and the projected area (Figure 4C) as generally described above.
• This slatted vane method not only increases the flow area but also provides the additional benefit that when there is a negative incidence on the fan exit guide vane 50" allows air flow from the high-pressure, convex side of the fan exit guide vane 50" to the lower-pressure, concave side of the fan exit guide vane 50" which delays flow separation.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Control Of Turbines (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (8)

Cited By (3)

Families Citing this family (9)

Citations (4)

Family Cites Families (15)

• 2013
  • 2013-01-03 BR BR112014016602-1A patent/BR112014016602B1/pt active IP Right Grant
  • 2013-01-03 CA CA2853694A patent/CA2853694C/en active Active
  • 2013-01-03 SG SG11201402663XA patent/SG11201402663XA/en unknown
  • 2013-01-03 RU RU2014130443A patent/RU2647558C2/ru active
  • 2013-01-03 JP JP2014551302A patent/JP2015503705A/ja active Pending
  • 2013-01-03 EP EP13735909.7A patent/EP2802745A4/en not_active Withdrawn
  • 2013-01-03 WO PCT/US2013/020040 patent/WO2013106223A1/en active Application Filing
  • 2013-01-03 CN CN201380005057.4A patent/CN104040117A/zh active Pending
• 2016
  • 2016-09-12 JP JP2016177200A patent/JP2017015095A/ja active Pending

Patent Citations (4)

Non-Patent Citations (1)

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