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
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/14—Form or construction
  • F01D5/141—Shape, i.e. outer, aerodynamic form
  • F01D5/146—Shape, i.e. outer, aerodynamic form of blades with tandem configuration, split blades or slotted blades
• • 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
  • 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
• • 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
  • F05D2240/00—Components
  • F05D2240/10—Stators
  • F05D2240/12—Fluid guiding means, e.g. vanes
  • F05D2240/121—Fluid guiding means, e.g. vanes related to the leading edge of a stator vane

Definitions

• the present application relates to a gas turbine engine having an improved fuel consumption based upon a combination of operational parameters.
• Gas turbine engines typically include a fan which drives air into a bypass duct, and also into a compressor section. The air is compressed in the compressor section, and delivered into a combustor section where it is mixed with fuel and burned. Products of this combustion pass downstream over turbine rotors, driving the turbine rotors to rotate.
• a gas turbine engine has a core section defined about an axis, a fan section delivering a first portion of air into the core section and a second portion of air into a bypass duct.
• a bypass ratio is defined as the ratio of the second portion compared to the first portion.
• the bypass ratio is greater than or equal to about 8.0.
• the air delivered into the core section is delivered into a low pressure compressor, and then into a high pressure compressor. Air from the high pressure compressor is delivered into a combustion section where it is mixed with fuel and ignited. Products of the combustion pass downstream over a high pressure turbine section and then a low pressure turbine section. An expansion ratio across the low pressure turbine section is greater than or equal to about 5.0.
• the low pressure turbine section drives the low pressure compressor section, and the fan through a gear reduction, with the gear reduction having a gear ratio greater than or equal to about 2.4.
• the gear ratio is greater than or equal to about 2.5.
• the gear ratio is less than or equal to about 4.2.
• the expansion ratio is greater than or equal to about 5.7.
• the bypass ratio is greater than or equal to 10.
• the fan has an outer diameter that is greater than an outer diameter of the low pressure turbine section.
• the gear reduction is greater than or equal to 2.4.
• the gear reduction is less than or equal to 4.2.
• the expansion ratio is greater than or equal to 5.0.
• the bypass ratio is greater than or equal to 8.
• a method of operating a gas turbine engine includes the steps of driving a fan to deliver a first portion of air into a bypass duct and a second portion of air into a low pressure compressor.
• a bypass ratio of the first portion to the second portion is greater than or equal to 8.0.
• the first portion of air is delivered into the low pressure compressor, into a high pressure compressor, and then into a combustion section.
• the air is mixed with fuel and ignited. Products of the combustion pass downstream over a high pressure turbine, and then a low pressure turbine.
• the low pressure turbine section is operated with an expansion ratio greater than or equal to 5.0.
• the low pressure turbine section is driven to rotate, and in turn rotates the low pressure compressor and fan through a gear reduction.
• the gear reduction has a ratio of greater than or equal to 2.4.
• the gear reduction is greater than or equal to 2.4.
• the gear reduction is less than or equal to 4.2.
• the expansion ratio is greater than or equal to 5.0.
• the bypass ratio is greater than or equal to 8.
• the fan has an outer diameter that is greater than an outer diameter of the low pressure turbine section.
• a gas turbine engine has a core section defined about an axis.
• a fan section is mounted at least partially around the core section to define a fan bypass flow path.
• a plurality of fan exit guide vanes are in communication with the fan bypass flow path and are rotatable about an axis of rotation to vary an effective fan nozzle exit area for the fan bypass flow path.
• the plurality of fan exit guide vanes are independently rotatable, and are simultaneously rotatable.
• the plurality of fan exit guide vanes are mounted within an intermediate engine case structure, with each including a pivotable portion rotatable about the axis of rotation relative a fixed portion.
• the pivotable portion includes a leading edge flap.
• a bypass ratio compares the air delivered by the fan section into a bypass duct to the amount of air delivered into the core section that is greater than 10, expansion ratio across a low pressure turbine section that is greater than 5, and the low pressure turbine section driving the fan section through a gear reduction, with the gear reduction having a ratio greater than 2.5.
• 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.
• FIG. 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 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, or expansion, ratio greater than five (5).
• 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 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.
• 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 0.8M and 35,000 feet.
• 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.
• the use of the gear reduction 22 allows control of a number of operational features in combination to achieve improved fuel efficiency.
• the expansion ratio (or pressure ratio) across the low pressure turbine which is the pressure entering the low pressure turbine section divided by the pressure leaving the low pressure turbine section was greater than or equal to about 5.0. In another embodiment, it was greater than or equal to about 5.7.
• the bypass ratio was greater than or equal to about 8.0. As mentioned earlier, in other embodiments, the bypass ratio may be greater than 10.0.
• the gear reduction ratio is greater than or equal to about 2.4 and less than or equal to about 4.2. Again, in embodiments, it is greater than 2.5.
• This combination provides a low pressure turbine section that can be very compact, and sized for very high aerodynamic efficiency with a small number of stages (3 to 5 as an example). Further, the maximum diameter of these stages can be minimized to improve installation clearance under the wings of an aircraft.

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

Applications Claiming Priority (2)

Publications (3)

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• 2013
  • 2013-01-17 EP EP13775841.3A patent/EP2809936B1/de active Active
  • 2013-01-17 WO PCT/US2013/021831 patent/WO2013154639A2/en not_active Ceased

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