US20150044052A1 - Geared Turbofan With Fan Blades Designed To Achieve Laminar Flow - Google Patents
Geared Turbofan With Fan Blades Designed To Achieve Laminar Flow Download PDFInfo
- Publication number
- US20150044052A1 US20150044052A1 US14/079,688 US201314079688A US2015044052A1 US 20150044052 A1 US20150044052 A1 US 20150044052A1 US 201314079688 A US201314079688 A US 201314079688A US 2015044052 A1 US2015044052 A1 US 2015044052A1
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- Prior art keywords
- cover
- end cap
- fan blade
- main body
- set forth
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- Abandoned
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Classifications
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- 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
- F04D29/02—Selection of particular materials
- F04D29/023—Selection of particular materials especially adapted for elastic fluid pumps
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- 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
- F01D5/18—Hollow blades, i.e. blades with cooling or heating channels or cavities; Heating, heat-insulating or cooling means on blades
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- 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
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- 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
- F01D5/145—Means for influencing boundary layers or secondary circulations
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- 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
- F01D5/147—Construction, i.e. structural features, e.g. of weight-saving hollow blades
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- 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
- F01D5/22—Blade-to-blade connections, e.g. for damping vibrations
- F01D5/225—Blade-to-blade connections, e.g. for damping vibrations by shrouding
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- 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
- F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
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- 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
- F04D29/26—Rotors specially for elastic fluids
- F04D29/32—Rotors specially for elastic fluids for axial flow pumps
- F04D29/321—Rotors specially for elastic fluids for axial flow pumps for axial flow compressors
- F04D29/324—Blades
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/36—Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user
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- 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
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- 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
- F05D2240/20—Rotors
- F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
- F05D2240/31—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor with roughened surfaces
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- 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
- F05D2250/00—Geometry
- F05D2250/10—Two-dimensional
- F05D2250/18—Two-dimensional patterned
- F05D2250/181—Two-dimensional patterned ridged
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- 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
- F05D2250/00—Geometry
- F05D2250/30—Arrangement of components
- F05D2250/31—Arrangement of components according to the direction of their main axis or their axis of rotation
- F05D2250/311—Arrangement of components according to the direction of their main axis or their axis of rotation the axes being in line
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- 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
- F05D2250/00—Geometry
- F05D2250/30—Arrangement of components
- F05D2250/32—Arrangement of components according to their shape
- F05D2250/321—Arrangement of components according to their shape asymptotic
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- 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
- F05D2250/00—Geometry
- F05D2250/30—Arrangement of components
- F05D2250/32—Arrangement of components according to their shape
- F05D2250/322—Arrangement of components according to their shape tangential
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- 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
- F05D2250/00—Geometry
- F05D2250/60—Structure; Surface texture
- F05D2250/62—Structure; Surface texture smooth or fine
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- 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
- F05D2300/00—Materials; Properties thereof
- F05D2300/10—Metals, alloys or intermetallic compounds
- F05D2300/17—Alloys
- F05D2300/173—Aluminium alloys, e.g. AlCuMgPb
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- 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
- F05D2300/00—Materials; Properties thereof
- F05D2300/10—Metals, alloys or intermetallic compounds
- F05D2300/17—Alloys
- F05D2300/174—Titanium alloys, e.g. TiAl
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- 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
- F05D2300/00—Materials; Properties thereof
- F05D2300/50—Intrinsic material properties or characteristics
- F05D2300/516—Surface roughness
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49316—Impeller making
- Y10T29/49336—Blade making
Definitions
- Gas turbine engines may be provided with a fan for delivering air to a compressor section and into a bypass section. From the compressor section, the air is compressed and delivered into a combustion section. The combustion section mixes fuel with the air and combusts the combination. Products of the combustion pass downstream over turbine rotors which are driven to rotate and, in turn, drive the compressor and the fan.
- a single turbine rotor may have driven a lower pressure compressor and a fan at the same speed. More recently, a gear reduction has been proposed such as intermediate the lower pressure compressor and the fan, such that the fan can rotate at lower speeds relative to the lower pressure compressor. With this change, the diameter of the fan has increased dramatically and its speed has decreased.
- hollow fan blades have been developed.
- One type of hollow fan blade has at least one channel and an outer cover attached over a main fan blade body to contain the channel.
- an end cap may be placed on the fan body.
- the interface of the ends of the end cap and the cover skin, relative to the main fan body, provides an interface that may be in the form of a step.
- a fan blade comprises a main body having an airfoil extending between a leading edge and a trailing edge.
- the fan blade has at least one of a channel closed by a cover, and an end cap covering at least one of the leading and trailing edges.
- At least one of a cover and an end cap has a pair of opposed ends.
- a step is defined extending from at least one of a suction wall and a pressure wall of the airfoil, to an outer surface of the one of a cover and an end cap at one of the opposed ends, and the step being less than or equal to about 0.010 inch (0.0254 centimeter) in dimension.
- the main body includes both the cover and the end cap, the end cap at the leading edge, wherein the steps are defined at each of the opposed ends of the cover on one of the suction wall and the pressure wall, and wherein the steps are defined at each of the opposed ends of the end cap on both the suction and pressure walls, and wherein all of the step dimensions are less than or equal to about 0.010 inch (0.0254 centimeter).
- an outer surface of the fan blade has a surface roughness.
- the surface roughness has a root means square value of less than about 60 ⁇ 10 ⁇ 6 inch on at least a portion of a radial length of the main body.
- a filler material is provided between each of the opposed ends of the end caps and cover and the main body, with the filler material reducing the size of the steps, and the filler material being part of the cover and the end cap for purposes of measuring the dimensions of the steps.
- an outer surface of the fan blade has a surface roughness.
- the surface roughness has a root means square value of less than about 60 ⁇ 10 ⁇ 6 inch on at least a portion of a radial length of the main body.
- a filler material is provided between the end of the one of an end cap and a cover and the main body, with the filler material reducing the size of the steps, and the filler material being part of the cover and the end cap for purposes of measuring the dimensions of the steps.
- the fan blade has a chord length.
- a ratio of the step dimension to the chord length is less than or equal to about 0.001.
- the step occurs over at least from 20% of a blade span, measured from a platform to a radially outer tip of the airfoil.
- the fan blade is designed to rotate with a fan tip corrected speed below 1225 ft/second (368 meters/second) at bucket cruise.
- a shroud connects the fan blade to an adjacent fan blade.
- At least one of the main body, cover, and cap is formed of aluminum or an aluminum alloy.
- At least one of the main body, cover, and cap is formed of titanium or a titanium alloy.
- At least one of the main body, cover, and cap is formed of composite.
- At least one of the main body is formed of composite, a metal, or an alloy, and wherein the cover or the cap is formed of titanium or a titanium alloy.
- a gas turbine engine comprises a fan drive turbine driving a fan rotor having a plurality of blades through a gear reduction.
- the blades include a main body having an airfoil extending between a leading edge, and a trailing edge and the blades having a chord length.
- the fan blade has at least one of a channel closed by a cover and an end cap covering at least one of the leading and trailing edges.
- At least one of a cover and an end cap has a pair of opposed ends.
- a step is defined extending from at least one of a suction wall and a pressure wall of the airfoil, to an outer surface of the one of a cover and an end cap at one of the opposed ends.
- a ratio of the step dimension to the chord length is less than or equal to about 0.001.
- the main body includes both the cover and the end cap, the end cap at the leading edge, wherein the steps are defined at each of the opposed ends of the cover on one of the suction wall and the pressure wall.
- the steps are defined at each of the opposed ends of the end cap on both the suction and pressure walls. All of the step dimensions have a ratio of less than or equal to about 0.001.
- a filler material is provided between each of the opposed ends of the end caps and cover and the main body.
- the filler material reduces the size of the step dimensions, and is part of the cover and the end cap.
- an outer surface of the fan blade has a surface roughness.
- the surface roughness has a root means square value of less than about 60 ⁇ 10 ⁇ 6 inch on at least a portion of a radial length of the main body.
- a filler material is provided between the end of the one of an end cap and a cover and the main body.
- the filler material reduces the size of the step dimensions, and is part of the one of the cover and the end cap.
- the step occurs over at least from 20% of a blade span, measured from the platform to a radially outer tip of the airfoil.
- the fan blade is designed to rotate with a fan tip corrected speed below 1225 ft/second (368 meters/second) at bucket cruise.
- a shroud connects adjacent ones of the blades.
- a method of manufacturing a fan blade comprising the steps of providing a main body extending between a leading edge and a trailing edge, and having a suction wall and a pressure wall.
- the main body has at least one of a channel enclosed by a cover, and an end cap covering at least one of the leading and trailing edges.
- At least one of a cover and an end cap is assembled to the main body, and defines a step between at least one of the suction and pressure walls and an end of the at least one of a cover and an end cap.
- the step is made to be less than or equal to about 0.010 inch (0.0254 centimeter) in dimension.
- the size of the step is reduced by adding a filler material which is considered part of the at least one of an end cap and a cover for purposes of measuring the step dimension.
- the main body includes both a cover and an end cap.
- a surface roughness of the outer surface of the main body, and the at least one of the cover and the end cap is made to be less than about 60 ⁇ 10 ⁇ 6 inch over at least a portion of a radial length of the main body.
- a machining step is utilized to reduce the surface roughness.
- the fan blade defines a chord length.
- a ratio of the step dimension to the chord length is less than or equal to about 0.001.
- a method of designing a fan blade comprising providing a main body having an airfoil extending between a leading edge and a trailing edge, and the fan blade having a chord length.
- the airfoil extends radially outwardly from a platform.
- the fan blade has at least one of a channel closed by a cover, and an end cap covering at least one of the leading and trailing edges.
- At least one of a cover and an end cap has a pair of opposed ends.
- a step is defined extending from at least one of a suction wall and a pressure wall of the airfoil to an outer surface of the one of a cover and an end cap at one of the opposed ends.
- a ratio of the step dimension to the chord length is less than or equal to about 0.001.
- an outer surface of the fan blade has a surface roughness which has a root means square value of less than about 60 ⁇ 10 ⁇ 6 inch on at least a portion of a radial length of the main body.
- FIG. 1A schematically shows a gas turbine engine.
- FIG. 1B is a side view of a removed fan blade.
- FIG. 1C shows the fan blade of FIG. 1B in an installed condition.
- FIG. 2 is a cross-sectional view of the fan blade of FIGS. 1B , 1 C.
- FIG. 3A is a detail of a location identified by A in FIG. 2 .
- FIG. 3 BA is a first possibility at an area identified by B in FIG. 2 .
- FIG. 3 BB shows a second possibility.
- FIG. 3C shows a possibility at an area identified by C in FIG. 2 .
- FIG. 4A shows a corrective method at the location of FIG. 3A .
- FIG. 4 BA shows a corrective method at the location of FIG. 3 BA.
- FIG. 4 BB shows a corrective method at the location of FIG. 3 BB.
- FIG. 4C shows a corrective method at the location of FIG. 3C .
- FIG. 5 explains a feature of the fan blade of FIGS. 1B-4C .
- FIG. 6 shows another embodiment.
- FIG. 1A schematically illustrates a gas turbine engine 20 .
- the gas turbine engine 20 is disclosed herein as a two-spool turbofan that generally incorporates a fan section 22 , a compressor section 24 , a combustor section 26 and a turbine section 28 .
- Alternative engines might include an augmentor section (not shown) among other systems or features.
- the fan section 22 drives air along a bypass flow path B in a bypass duct defined within a nacelle 15
- the compressor section 24 drives air along a core flow path C for compression and communication into the combustor section 26 then expansion through the turbine section 28 .
- the exemplary engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38 . It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided, and the location of bearing systems 38 may be varied as appropriate to the application.
- the low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42 , a low pressure compressor 44 and a low pressure turbine 46 .
- the inner shaft 40 is connected to the fan 42 through a speed change mechanism, which in exemplary gas turbine engine 20 is illustrated as a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool 30 .
- the high speed spool 32 includes an outer shaft 50 that interconnects a high pressure compressor 52 and high pressure turbine 54 .
- a combustor 56 is arranged in exemplary gas turbine 20 between the high pressure compressor 52 and the high pressure turbine 54 .
- a mid-turbine frame 57 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine 46 .
- the mid-turbine frame 57 further supports bearing systems 38 in the turbine section 28 .
- the inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis A which is collinear with their longitudinal axes.
- the core airflow is compressed by the low pressure compressor 44 then the high pressure compressor 52 , mixed and burned with fuel in the combustor 56 , then expanded over the high pressure turbine 54 and low pressure turbine 46 .
- the mid-turbine frame 57 includes airfoils 59 which are in the core airflow path C.
- the turbines 46 , 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion.
- gear system 48 may be located aft of combustor section 26 or even aft of turbine section 28
- fan section 22 may be positioned forward or aft of the location of gear system 48 .
- the engine 20 in one example is a high-bypass geared aircraft engine.
- the engine 20 bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10)
- the geared architecture 48 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 46 has a pressure ratio that is greater than about five.
- the engine 20 bypass ratio is greater than about ten (10:1)
- the fan diameter is significantly larger than that of the low pressure compressor 44
- the low pressure turbine 46 has a pressure ratio that is greater than about five 5:1.
- Low pressure turbine 46 pressure ratio is pressure measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle.
- the geared architecture 48 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 2.3:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans.
- the fan section 22 of the engine 20 is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet.
- TSFC Thrust Specific Fuel Consumption
- Low fan pressure ratio is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system.
- 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 [(Tram ° R)/(518.7° R)] 0.5 .
- the “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second.
- a fan blade 120 which may be utilized in the gas turbine engine 20 is illustrated in FIG. 1B having an airfoil 18 extending radially outwardly from a platform 124 , which may include, as shown, a dovetail.
- a leading edge 21 and a trailing edge 122 define the forward and rear limits of the airfoil.
- the airfoil 18 extends from a radially inner end 501 adjacent the platform 124 to a radially outer end 500 .
- a fan rotor 16 will receive the platform 124 to mount the fan blade with the airfoil 18 extending radially outwardly. As the rotor 16 is driven to rotate, it carries the fan blade 120 with it.
- FIG. 2 shows a cross-section of the fan blade 120 at the airfoil 18 .
- the leading edge 21 receives a cap 37 secured to a main body 128 .
- a cover 132 closes off cavities or channels 130 in the main body 128 .
- the main body 128 , the cap 37 and the cover 132 may all be formed of aluminum or various aluminum alloys. Other materials, such as titanium, titanium alloys or other appropriate metals, may alternatively be utilized for any one or more of the cap 37 , the cover 132 , and/or the main body 128 . Further, other, non-metallic materials, such as composites or plastics, may alternatively and/or additionally be utilized for any one or more of the cap 37 , the cover 132 , and/or the main body 128 .
- the fan blade 120 is shown having one cover 132 and channels 130 having a closed inner end, it is also possible that the main body 128 would provide a channel extending across its entire thickness with covers at each side. As shown, a plurality of ribs 126 separate the channels 130 in the cross-section illustrated in FIG. 2 . Filler material 100 may be deposited within the channels 130 and would typically be of a lighter weight than the main body 128 .
- the fan blades mentioned above having a cover 132 , or an end cap 37 could be defined as assembled fan blades. These assembled fan blades, applicant has recognized, create steps which could move the actual flow further from laminar than it might be with a solid fan blade.
- FIG. 3A an area identified by A in FIG. 2 is enlarged.
- the cap 37 has an end 137 , which is spaced above an outer surface 210 of the main body 128 . There is a step of a dimension d 1 between the two.
- FIG. 3 BA shows one possibility at the location B in FIG. 2 .
- the cover 132 has its end 139 spaced from the outer surface 210 by a step of a dimension d 2 . This would be a “negative” step.
- FIG. 3 BB shows the opposite wherein the cover 132 extends above the surface 210 by a dimension d 3 . This might be called a positive step.
- the steps must be minimized to achieve laminar flow.
- the steps should be less than or equal to about 0.010 inch (0.0254 centimeter). This requirement can be performed as part of a quality control step and, if any of the dimensions d 1 -d 3 are outside of this dimension, then corrective steps may be taken.
- a putty 301 may be included to take up the step and reduce the sudden change between the two surfaces.
- a chord length C for the blade airfoils 18 may be defined as shown in FIG. 5 .
- the dimensions d 1 -d 3 could be defined as being kept within a maximum ratio with regard to the chord length C.
- the maximum allowable step was 0.010 inch (0.0254 centimeter)
- the chord length C was 10 inches (25.14 centimeters).
- a ratio of d 1 -d 3 to C is less than or equal to about 0.001.
- C is measured at a tip of the airfoil 18 , and between its leading and trailing edges.
- the reduction of the steps may be provided on each of the suction side 99 and pressure side 97 (see FIG. 2 ) of the airfoil at all positions wherein there is a step.
- the corrective measure may be more important at different radial locations between the radial ends 500 and 501 of the airfoil 18 (see FIG. 1B ).
- the putty 301 is considered part of the cover 132 or end cap 37 . While putty is disclosed, other filler materials may be used.
- FIG. 3C shows yet another concern.
- a surface roughness at the surface 210 may be identified as surface irregularities 211 and may have a highest dimension d 4 . It would be desirable that this surface roughness be minimized Applicant has found that maintaining a surface roughness with a root means square value of less than about 60 ⁇ 10 ⁇ 6- inch would result in a fan blade providing more laminar flow.
- this may be achieved by machining such as applying a polishing or smoothing tool 310 to the irregularities 211 .
- the most important portion of the fan blade to have the required smoothness are from about 20% of the blade span radially outwardly, measured along a length of airfoil 18 to 100% of the airfoil 18 , at its tip.
- a fan blade having the disclosed characteristics are most beneficial when a fan tip corrected speed is below about 1225 ft/second at bucket cruise, and even more beneficial when the fan speed is below 1150 ft/second. Further, the benefits are more pronounced when the fan rotor carries 26 or fewer fan blades.
- an assembled fan blade having either the small step size or the very smooth outer surface will achieve laminar flow over a greater percentage of its surface area.
- These treatments can be applied at any radial location between ends 501 and 500 or over all of those portions.
- they may be provided on only the suction side 99 , only the pressure side 97 or both.
- FIG. 6 shows an alternate embodiment fan rotor 300 wherein blades 302 and 304 have a shroud 306 extending between them.
- the shroud 306 provides additional rigidity to the structure to enhance laminar flow across the fan blades 302 , 304 .
- the shroud of this embodiment may be used in conjunction with any of the foregoing surface treatments described with respect to the embodiments of FIGS. 2-5 .
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Abstract
Description
- This application claims priority to U.S. Provisional Application 61/727,786 filed Nov. 19, 2012, and U.S. Provisional Application 61/884,295, filed Sep. 30, 2013.
- Gas turbine engines may be provided with a fan for delivering air to a compressor section and into a bypass section. From the compressor section, the air is compressed and delivered into a combustion section. The combustion section mixes fuel with the air and combusts the combination. Products of the combustion pass downstream over turbine rotors which are driven to rotate and, in turn, drive the compressor and the fan.
- Historically, a single turbine rotor may have driven a lower pressure compressor and a fan at the same speed. More recently, a gear reduction has been proposed such as intermediate the lower pressure compressor and the fan, such that the fan can rotate at lower speeds relative to the lower pressure compressor. With this change, the diameter of the fan has increased dramatically and its speed has decreased.
- As the fan blade diameter increases, its weight be expected to increase. To address this increase, hollow fan blades have been developed. One type of hollow fan blade has at least one channel and an outer cover attached over a main fan blade body to contain the channel. In addition, an end cap may be placed on the fan body.
- The interface of the ends of the end cap and the cover skin, relative to the main fan body, provides an interface that may be in the form of a step.
- In a featured embodiment, a fan blade comprises a main body having an airfoil extending between a leading edge and a trailing edge. The fan blade has at least one of a channel closed by a cover, and an end cap covering at least one of the leading and trailing edges. At least one of a cover and an end cap has a pair of opposed ends. A step is defined extending from at least one of a suction wall and a pressure wall of the airfoil, to an outer surface of the one of a cover and an end cap at one of the opposed ends, and the step being less than or equal to about 0.010 inch (0.0254 centimeter) in dimension.
- In another embodiment according to the previous embodiment, the main body includes both the cover and the end cap, the end cap at the leading edge, wherein the steps are defined at each of the opposed ends of the cover on one of the suction wall and the pressure wall, and wherein the steps are defined at each of the opposed ends of the end cap on both the suction and pressure walls, and wherein all of the step dimensions are less than or equal to about 0.010 inch (0.0254 centimeter).
- In another embodiment according to any of the previous embodiments, an outer surface of the fan blade has a surface roughness. The surface roughness has a root means square value of less than about 60×10−6 inch on at least a portion of a radial length of the main body.
- In another embodiment according to any of the previous embodiments, a filler material is provided between each of the opposed ends of the end caps and cover and the main body, with the filler material reducing the size of the steps, and the filler material being part of the cover and the end cap for purposes of measuring the dimensions of the steps.
- In another embodiment according to any of the previous embodiments, an outer surface of the fan blade has a surface roughness. The surface roughness has a root means square value of less than about 60×10−6 inch on at least a portion of a radial length of the main body.
- In another embodiment according to any of the previous embodiments, a filler material is provided between the end of the one of an end cap and a cover and the main body, with the filler material reducing the size of the steps, and the filler material being part of the cover and the end cap for purposes of measuring the dimensions of the steps.
- In another embodiment according to any of the previous embodiments, the fan blade has a chord length. A ratio of the step dimension to the chord length is less than or equal to about 0.001.
- In another embodiment according to any of the previous embodiments, the step occurs over at least from 20% of a blade span, measured from a platform to a radially outer tip of the airfoil.
- In another embodiment according to any of the previous embodiments, the fan blade is designed to rotate with a fan tip corrected speed below 1225 ft/second (368 meters/second) at bucket cruise.
- In another embodiment according to any of the previous embodiments, a shroud connects the fan blade to an adjacent fan blade.
- In another embodiment according to any of the previous embodiments, at least one of the main body, cover, and cap is formed of aluminum or an aluminum alloy.
- In another embodiment according to any of the previous embodiments, at least one of the main body, cover, and cap is formed of titanium or a titanium alloy.
- In another embodiment according to any of the previous embodiments, at least one of the main body, cover, and cap is formed of composite.
- In another embodiment according to any of the previous embodiments, at least one of the main body is formed of composite, a metal, or an alloy, and wherein the cover or the cap is formed of titanium or a titanium alloy.
- In another featured embodiment, a gas turbine engine comprises a fan drive turbine driving a fan rotor having a plurality of blades through a gear reduction. The blades include a main body having an airfoil extending between a leading edge, and a trailing edge and the blades having a chord length. The fan blade has at least one of a channel closed by a cover and an end cap covering at least one of the leading and trailing edges. At least one of a cover and an end cap has a pair of opposed ends. A step is defined extending from at least one of a suction wall and a pressure wall of the airfoil, to an outer surface of the one of a cover and an end cap at one of the opposed ends. A ratio of the step dimension to the chord length is less than or equal to about 0.001.
- In another embodiment according to the previous embodiment, the main body includes both the cover and the end cap, the end cap at the leading edge, wherein the steps are defined at each of the opposed ends of the cover on one of the suction wall and the pressure wall. The steps are defined at each of the opposed ends of the end cap on both the suction and pressure walls. All of the step dimensions have a ratio of less than or equal to about 0.001.
- In another embodiment according to any of the previous embodiments, a filler material is provided between each of the opposed ends of the end caps and cover and the main body. The filler material reduces the size of the step dimensions, and is part of the cover and the end cap.
- In another embodiment according to any of the previous embodiments, an outer surface of the fan blade has a surface roughness. The surface roughness has a root means square value of less than about 60×10−6 inch on at least a portion of a radial length of the main body.
- In another embodiment according to any of the previous embodiments, a filler material is provided between the end of the one of an end cap and a cover and the main body. The filler material reduces the size of the step dimensions, and is part of the one of the cover and the end cap.
- In another embodiment according to any of the previous embodiments, the step occurs over at least from 20% of a blade span, measured from the platform to a radially outer tip of the airfoil.
- In another embodiment according to any of the previous embodiments, the fan blade is designed to rotate with a fan tip corrected speed below 1225 ft/second (368 meters/second) at bucket cruise.
- In another embodiment according to any of the previous embodiments, a shroud connects adjacent ones of the blades.
- In another featured embodiment, a method of manufacturing a fan blade comprising the steps of providing a main body extending between a leading edge and a trailing edge, and having a suction wall and a pressure wall. The main body has at least one of a channel enclosed by a cover, and an end cap covering at least one of the leading and trailing edges. At least one of a cover and an end cap is assembled to the main body, and defines a step between at least one of the suction and pressure walls and an end of the at least one of a cover and an end cap. The step is made to be less than or equal to about 0.010 inch (0.0254 centimeter) in dimension.
- In another embodiment according to the previous embodiment, the size of the step is reduced by adding a filler material which is considered part of the at least one of an end cap and a cover for purposes of measuring the step dimension.
- In another embodiment according to any of the previous embodiments, the main body includes both a cover and an end cap. There are at least four steps associated with ends of the cover spaced toward both the leading and trailing edges and ends of the end cap on each of the pressure and suction walls. All of the dimensions of the steps are made to be less than or equal to about 0.010 inch (0.0254 centimeter).
- In another embodiment according to any of the previous embodiments, a surface roughness of the outer surface of the main body, and the at least one of the cover and the end cap is made to be less than about 60×10−6 inch over at least a portion of a radial length of the main body.
- In another embodiment according to any of the previous embodiments, a machining step is utilized to reduce the surface roughness.
- In another embodiment according to any of the previous embodiments, the fan blade defines a chord length. A ratio of the step dimension to the chord length is less than or equal to about 0.001.
- In another featured embodiment, a method of designing a fan blade comprising providing a main body having an airfoil extending between a leading edge and a trailing edge, and the fan blade having a chord length. The airfoil extends radially outwardly from a platform. The fan blade has at least one of a channel closed by a cover, and an end cap covering at least one of the leading and trailing edges. At least one of a cover and an end cap has a pair of opposed ends. A step is defined extending from at least one of a suction wall and a pressure wall of the airfoil to an outer surface of the one of a cover and an end cap at one of the opposed ends. A ratio of the step dimension to the chord length is less than or equal to about 0.001.
- In another embodiment according to the previous embodiment, an outer surface of the fan blade has a surface roughness which has a root means square value of less than about 60×10−6 inch on at least a portion of a radial length of the main body.
- These and other features may be best understood from the following drawings and specification.
-
FIG. 1A schematically shows a gas turbine engine. -
FIG. 1B is a side view of a removed fan blade. -
FIG. 1C shows the fan blade ofFIG. 1B in an installed condition. -
FIG. 2 is a cross-sectional view of the fan blade ofFIGS. 1B , 1C. -
FIG. 3A is a detail of a location identified by A inFIG. 2 . - FIG. 3BA is a first possibility at an area identified by B in
FIG. 2 . - FIG. 3BB shows a second possibility.
-
FIG. 3C shows a possibility at an area identified by C inFIG. 2 . -
FIG. 4A shows a corrective method at the location ofFIG. 3A . - FIG. 4BA shows a corrective method at the location of FIG. 3BA.
- FIG. 4BB shows a corrective method at the location of FIG. 3BB.
-
FIG. 4C shows a corrective method at the location ofFIG. 3C . -
FIG. 5 explains a feature of the fan blade ofFIGS. 1B-4C . -
FIG. 6 shows another embodiment. -
FIG. 1A schematically illustrates agas turbine engine 20. Thegas turbine engine 20 is disclosed herein as a two-spool turbofan that generally incorporates afan section 22, acompressor section 24, acombustor section 26 and aturbine section 28. Alternative engines might include an augmentor section (not shown) among other systems or features. Thefan section 22 drives air along a bypass flow path B in a bypass duct defined within anacelle 15, while thecompressor section 24 drives air along a core flow path C for compression and communication into thecombustor section 26 then expansion through theturbine section 28. Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures. - The
exemplary engine 20 generally includes alow speed spool 30 and ahigh speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an enginestatic structure 36 viaseveral bearing systems 38. It should be understood that various bearingsystems 38 at various locations may alternatively or additionally be provided, and the location of bearingsystems 38 may be varied as appropriate to the application. - The
low speed spool 30 generally includes aninner shaft 40 that interconnects afan 42, alow pressure compressor 44 and alow pressure turbine 46. Theinner shaft 40 is connected to thefan 42 through a speed change mechanism, which in exemplarygas turbine engine 20 is illustrated as a gearedarchitecture 48 to drive thefan 42 at a lower speed than thelow speed spool 30. Thehigh speed spool 32 includes anouter shaft 50 that interconnects ahigh pressure compressor 52 andhigh pressure turbine 54. Acombustor 56 is arranged inexemplary gas turbine 20 between thehigh pressure compressor 52 and thehigh pressure turbine 54. Amid-turbine frame 57 of the enginestatic structure 36 is arranged generally between thehigh pressure turbine 54 and thelow pressure turbine 46. Themid-turbine frame 57 furthersupports bearing systems 38 in theturbine section 28. Theinner shaft 40 and theouter shaft 50 are concentric and rotate via bearingsystems 38 about the engine central longitudinal axis A which is collinear with their longitudinal axes. - The core airflow is compressed by the
low pressure compressor 44 then thehigh pressure compressor 52, mixed and burned with fuel in thecombustor 56, then expanded over thehigh pressure turbine 54 andlow pressure turbine 46. Themid-turbine frame 57 includesairfoils 59 which are in the core airflow path C. Theturbines low speed spool 30 andhigh speed spool 32 in response to the expansion. It will be appreciated that each of the positions of thefan section 22,compressor section 24,combustor section 26,turbine section 28, and fandrive gear system 48 may be varied. For example,gear system 48 may be located aft ofcombustor section 26 or even aft ofturbine section 28, andfan section 22 may be positioned forward or aft of the location ofgear system 48. - The
engine 20 in one example is a high-bypass geared aircraft engine. In a further example, theengine 20 bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10), the gearedarchitecture 48 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 and thelow pressure turbine 46 has a pressure ratio that is greater than about five. In one disclosed embodiment, theengine 20 bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of thelow pressure compressor 44, and thelow pressure turbine 46 has a pressure ratio that is greater than about five 5:1.Low pressure turbine 46 pressure ratio is pressure measured prior to inlet oflow pressure turbine 46 as related to the pressure at the outlet of thelow pressure turbine 46 prior to an exhaust nozzle. The gearedarchitecture 48 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 2.3:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans. - A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The
fan section 22 of theengine 20 is 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 a Fan Exit Guide Vane (“FEGV”) system. 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 [(Tram ° R)/(518.7° R)]0.5. The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second. - A
fan blade 120 which may be utilized in thegas turbine engine 20 is illustrated inFIG. 1B having anairfoil 18 extending radially outwardly from aplatform 124, which may include, as shown, a dovetail. A leadingedge 21 and a trailingedge 122 define the forward and rear limits of the airfoil. As shown inFIG. 1B , theairfoil 18 extends from a radiallyinner end 501 adjacent theplatform 124 to a radiallyouter end 500. - As shown in
FIG. 1C , afan rotor 16 will receive theplatform 124 to mount the fan blade with theairfoil 18 extending radially outwardly. As therotor 16 is driven to rotate, it carries thefan blade 120 with it. -
FIG. 2 shows a cross-section of thefan blade 120 at theairfoil 18. As shown, the leadingedge 21 receives acap 37 secured to amain body 128. Acover 132 closes off cavities orchannels 130 in themain body 128. Themain body 128, thecap 37 and thecover 132 may all be formed of aluminum or various aluminum alloys. Other materials, such as titanium, titanium alloys or other appropriate metals, may alternatively be utilized for any one or more of thecap 37, thecover 132, and/or themain body 128. Further, other, non-metallic materials, such as composites or plastics, may alternatively and/or additionally be utilized for any one or more of thecap 37, thecover 132, and/or themain body 128. - In addition, while the
fan blade 120 is shown having onecover 132 andchannels 130 having a closed inner end, it is also possible that themain body 128 would provide a channel extending across its entire thickness with covers at each side. As shown, a plurality ofribs 126 separate thechannels 130 in the cross-section illustrated inFIG. 2 .Filler material 100 may be deposited within thechannels 130 and would typically be of a lighter weight than themain body 128. - Applicant has discovered that with the increasing diameter of the
fan blade 120 when utilized in geared gas turbine engine, surface smoothness becomes important. If a laminar flow can be achieved at the surface of the airfoil, the fuel burn efficiency and the fan efficiency can be increased dramatically. However, it is challenging to achieve laminar flow onfan blades 120 and, in particular, as their diameter increases and their speed decreases. - In fact, the fan blades mentioned above having a
cover 132, or anend cap 37, could be defined as assembled fan blades. These assembled fan blades, applicant has recognized, create steps which could move the actual flow further from laminar than it might be with a solid fan blade. - As shown in
FIG. 3A , an area identified by A inFIG. 2 is enlarged. As shown, thecap 37 has anend 137, which is spaced above anouter surface 210 of themain body 128. There is a step of a dimension d1 between the two. - Similarly, FIG. 3BA shows one possibility at the location B in
FIG. 2 . Here, thecover 132 has itsend 139 spaced from theouter surface 210 by a step of a dimension d2. This would be a “negative” step. - FIG. 3BB shows the opposite wherein the
cover 132 extends above thesurface 210 by a dimension d3. This might be called a positive step. - Applicant has discovered that these steps must be minimized to achieve laminar flow. In particular, the steps should be less than or equal to about 0.010 inch (0.0254 centimeter). This requirement can be performed as part of a quality control step and, if any of the dimensions d1-d3 are outside of this dimension, then corrective steps may be taken. As an example, as shown in
FIGS. 4A , 4BB and 4BA, aputty 301 may be included to take up the step and reduce the sudden change between the two surfaces. - Stated another way, a chord length C for the
blade airfoils 18 may be defined as shown inFIG. 5 . In one embodiment, rather than the 0.010 inch (0.0254 centimeter) maximum, the dimensions d1-d3 could be defined as being kept within a maximum ratio with regard to the chord length C. In one embodiment, the maximum allowable step was 0.010 inch (0.0254 centimeter), and the chord length C was 10 inches (25.14 centimeters). In this embodiment, a ratio of d1-d3 to C is less than or equal to about 0.001. For this embodiment, C is measured at a tip of theairfoil 18, and between its leading and trailing edges. - As mentioned above, the reduction of the steps may be provided on each of the
suction side 99 and pressure side 97 (seeFIG. 2 ) of the airfoil at all positions wherein there is a step. In addition, the corrective measure may be more important at different radial locations between the radial ends 500 and 501 of the airfoil 18 (seeFIG. 1B ). - For purposes of measuring the step height after the corrective steps of
FIGS. 4A , 4BA, and 4BB, theputty 301 is considered part of thecover 132 orend cap 37. While putty is disclosed, other filler materials may be used. -
FIG. 3C shows yet another concern. A surface roughness at thesurface 210 may be identified assurface irregularities 211 and may have a highest dimension d4. It would be desirable that this surface roughness be minimized Applicant has found that maintaining a surface roughness with a root means square value of less than about 60×10−6-inch would result in a fan blade providing more laminar flow. - As shown in
FIG. 4C , this may be achieved by machining such as applying a polishing or smoothingtool 310 to theirregularities 211. - Applicant has also discovered that the most important portion of the fan blade to have the required smoothness are from about 20% of the blade span radially outwardly, measured along a length of
airfoil 18 to 100% of theairfoil 18, at its tip. - In addition, applicant has determined that the results achieved by a fan blade having the disclosed characteristics are most beneficial when a fan tip corrected speed is below about 1225 ft/second at bucket cruise, and even more beneficial when the fan speed is below 1150 ft/second. Further, the benefits are more pronounced when the fan rotor carries 26 or fewer fan blades.
- Now, an assembled fan blade having either the small step size or the very smooth outer surface will achieve laminar flow over a greater percentage of its surface area. These treatments can be applied at any radial location between ends 501 and 500 or over all of those portions. In addition, they may be provided on only the
suction side 99, only thepressure side 97 or both. -
FIG. 6 shows an alternateembodiment fan rotor 300 whereinblades shroud 306 extending between them. Theshroud 306 provides additional rigidity to the structure to enhance laminar flow across thefan blades FIGS. 2-5 . - Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure.
Claims (30)
Priority Applications (1)
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US14/079,688 US20150044052A1 (en) | 2012-11-19 | 2013-11-14 | Geared Turbofan With Fan Blades Designed To Achieve Laminar Flow |
Applications Claiming Priority (3)
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US201261727786P | 2012-11-19 | 2012-11-19 | |
US201361884295P | 2013-09-30 | 2013-09-30 | |
US14/079,688 US20150044052A1 (en) | 2012-11-19 | 2013-11-14 | Geared Turbofan With Fan Blades Designed To Achieve Laminar Flow |
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US20150044052A1 true US20150044052A1 (en) | 2015-02-12 |
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US14/079,688 Abandoned US20150044052A1 (en) | 2012-11-19 | 2013-11-14 | Geared Turbofan With Fan Blades Designed To Achieve Laminar Flow |
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EP (2) | EP2920072B8 (en) |
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US20180038386A1 (en) * | 2016-08-08 | 2018-02-08 | United Technologies Corporation | Fan blade with composite cover |
US20180362024A1 (en) * | 2017-06-16 | 2018-12-20 | Volkswagen Aktiengesellschaft | Method For Assisting A Maneuvering Procedure Of A Motor Vehicle, And System For Assisting A Maneuvering Procedure Of A Motor Vehicle |
US10808718B2 (en) | 2013-10-30 | 2020-10-20 | Raytheon Technologies Corporation | Fan blade composite segments |
US11499432B2 (en) * | 2015-07-03 | 2022-11-15 | Safran Aircraft Engines | Method for altering the law of twist of the aerodynamic surface of a gas turbine engine fan blade |
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Also Published As
Publication number | Publication date |
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EP2920072A2 (en) | 2015-09-23 |
EP3772567B1 (en) | 2022-06-01 |
EP2920072B1 (en) | 2020-09-02 |
EP2920072B8 (en) | 2020-11-11 |
EP2920072A4 (en) | 2016-08-10 |
EP3772567A1 (en) | 2021-02-10 |
WO2014078467A2 (en) | 2014-05-22 |
WO2014078467A3 (en) | 2014-08-07 |
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