Engine airfoil metal edge

Abstract

An airfoil for a gas turbine engine is provided, the airfoil defining a spanwise direction, a root end, a tip end, a leading edge end, and a trailing edge end. The airfoil includes a main body extending in the spanwise direction between the root end and the tip end, the main body being formed of a composite material, and a shaped leading edge member attached to the main body and positioned at the leading edge end of the airfoil, the shaped leading edge member being formed at least partially of a metallic material and defining a nonlinear patterned leading edge of the airfoil.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Polish patent application No. P.437428 filed on March 26, 2021.

[0003] Federally funded research

[0004] This invention was made with government support under Contract Reference No. DTFAWA-15-A-80013 awarded by the Federal Aviation Administration. The U.S. Government may have certain rights in this invention. Technical Field

[0005] The present subject matter relates generally to a gas turbine engine component, or more particularly to an airfoil having a metal rim. Background Art

[0006] A gas turbine engine generally includes a fan and a turbine arranged in flow communication with each other. Furthermore, the turbine of a gas turbine engine generally includes, in series flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is supplied from the fan to the inlet of the compressor section, where one or more axial compressors gradually compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and combusted within the combustion section to provide combustion gases. From the combustion section, the combustion gases are directed to the turbine section. The combustion gas flow through the turbine section drives the turbine section and is then directed through the exhaust section, for example, to the atmosphere.

[0007] The fan includes a plurality of circumferentially spaced fan blades extending radially outward from a rotor disk. Rotation of the fan blades generates airflow through an inlet to the turbine, as well as airflow over the turbine. In some gas turbine engines, a plurality of outlet guide vanes are provided downstream of the fan to correct the airflow from the fan, for example, to increase the amount of thrust generated by the fan.

[0008] Improvements to exit guide vanes and other airfoils within gas turbine engines would be welcome in the art. Summary of the Invention

[0009] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0010] In an exemplary embodiment of the present disclosure, an airfoil for a gas turbine engine is provided, the airfoil defining a spanwise direction, a root end, a tip end, a leading edge end, and a trailing edge end. The airfoil includes a main body extending spanwise between the root end and the tip end, the main body being formed of a composite material; and a shaped leading edge member attached to the main body, the shaped leading edge member being positioned at the leading edge end of the airfoil, the shaped leading edge member being at least partially formed of a metallic material and defining a nonlinear patterned leading edge of the airfoil.

[0011] In one exemplary aspect of the present disclosure, a method for forming an airfoil is provided, comprising adding a conductive layer to a filler for an edge member of the airfoil; and electroforming an edge shell over the filler, the edge shell being formed of a metallic material.

[0012] In another exemplary aspect of the present disclosure, an airfoil for a gas turbine engine is provided, the airfoil defining a spanwise direction, a root end, and a tip end. The airfoil includes a main body extending along the spanwise direction between the root end and the tip end, the main body being formed of a composite material; an edge member including an edge shell formed of the metal material and at least partially defining an inner cavity; a filler positioned in the inner cavity; and an intermediate layer between the filler and the edge shell and extending at least partially over the main body, wherein the intermediate layer is bonded to the main body, and the edge shell is bonded to the intermediate layer.

[0013] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A full and enabling disclosure of the invention, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0015] Figure 1 is a schematic cross-sectional view of an exemplary gas turbine engine according to various embodiments of the present subject matter.

[0016] Figure 2 It can be used with Figure 1 A perspective view of a fan frame used with an exemplary gas turbine engine.

[0017] Figure 3 is a perspective view of a dual outlet guide vane according to an exemplary embodiment of the present subject matter.

[0018] Figure 4 yes Figure 3 Side view of the first guide vane of the dual outlet guide vanes.

[0019] Figure 5 yes Figure 4 The first guide blade edge Figure 4 Cross-sectional view along midline 5-5.

[0020] Figure 6 yes Figure 5 A close-up view of the leading edge member of the first guide vane.

[0021] Figure 7 is a close-up view of a leading edge member according to an alternative exemplary embodiment of the present subject matter.

[0022] Figure 8 yes Figure 5 Another close up view of the leading edge member of the first guide vane at the junction between the leading edge member and the body of the first guide vane.

[0023] Figure 9 is a close-up view of a leading edge member according to another alternative exemplary embodiment of the present subject matter.

[0024] Figure 10 is a flow chart of a method of forming an airfoil according to an exemplary aspect of the present disclosure. DETAILED DESCRIPTION

[0025] Reference will now be made in detail to the present embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter references to refer to features in the drawings. The same or similar reference numerals in the drawings and the description are used to refer to the same or similar parts of the invention.

[0026] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. In addition, all embodiments described herein should be considered exemplary unless otherwise specifically stated.

[0027] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to denote the position or importance of a single component.

[0028] The terms "fore" and "aft" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, with respect to a gas turbine engine, the forward position refers to the position closer to the engine inlet, and the aft position refers to the position closer to the engine nozzle or exhaust.

[0029] In addition, the terms "upstream" and "downstream" refer to relative directions relative to the flow of fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction to which the fluid flows.

[0030] The terms "coupled," "fixed," "attached," and the like refer to both direct coupling, fixing, or attachment, as well as indirect coupling, fixing, or attachment through one or more intermediate components or features, unless otherwise specified herein.

[0031] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0032] Approximate language, as used in this specification and claims, is used to modify any quantitative representation that can be permissibly varied without resulting in a change in the basic function to which it relates. Thus, a value modified by one or more terms, such as "about," "approximately," and "substantially," is not limited to the precise value specified. In at least some instances, approximate language may correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximate language may refer to within a margin of 1, 2, 4, 10, 15, or 20%. These approximate margins may apply to a single value, to one or both endpoints of a range of values, and / or to the margin of a range between the endpoints.

[0033] Here and throughout the specification and claims, range limitations are combined and interchangeable, and these ranges are identified and include all sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein include the endpoints, and the endpoints are independently combinable with each other.

[0034] In certain aspects of the present disclosure, an airfoil for a gas turbine engine is provided. The airfoil generally includes a shaped leading edge member attached to a body and positioned at a leading edge end of the airfoil. The shaped leading edge member is formed at least in part from a metallic material and defines a nonlinear patterned leading edge of the airfoil.

[0035] In certain exemplary aspects, one or more aspects of the shaped leading edge member can be formed using an electroforming process. In this manner, the shaped leading edge member can include a filler material, an intermediate layer at least partially positioned above the filler material, and a shell. The filler material can be a non-conductive material, and the intermediate layer can be a conductive layer. The shell can be electroformed above the intermediate layer.

[0036] In certain configurations, an intermediate layer may be bonded to the main body of the airfoil to attach the shaped leading edge member to the main body of the airfoil.

[0037] An airfoil having a shaped leading edge member according to this configuration can provide a reduction in fan noise attenuation. Furthermore, incorporating a shaped leading edge member according to the present disclosure can also help the airfoil meet structural requirements, such as bird strikes, while maintaining a relatively low overall weight. Furthermore, incorporating a shaped leading edge member according to the present disclosure can also provide a strong bond between the metal portion of the shaped leading edge member and the main body, which can be formed of a composite material, while also fully encapsulating a lightweight foam filler material.

[0038] Reference is now made to the drawings, wherein like numerals refer to like elements throughout. Figure 1 is a schematic cross-sectional view of a gas turbine engine according to an exemplary embodiment of the present disclosure. More specifically, Figure 1 In the embodiment of the present invention, the gas turbine engine is a high bypass turbofan jet engine, referred to herein as "turbofan engine 10". Figure 1 As shown, the turbofan engine 10 defines axial directions A (extending parallel to a longitudinal centerline 12 provided for reference), radial directions R, and circumferential directions C (see FIG. Figure 2 Generally speaking, the turbofan 10 includes a fan section 14 and a turbine 16 disposed downstream of the fan section 14 .

[0039] The depicted exemplary turbine 16 generally includes a generally tubular casing 18 defining an annular inlet 20. Casing 18 surrounds, in series flow relationship, a compressor section including a supercharger or low-pressure (LP) compressor 22 and a high-pressure (HP) compressor 24; a combustion section 26; a turbine section including a high-pressure (HP) turbine 28 and a low-pressure (LP) turbine 30; and an exhaust nozzle section 32. A high-pressure (HP) shaft or spool 34 drivingly connects the HP turbine 28 to the HP compressor 24. A low-pressure (LP) shaft or spool 36 drivingly connects the LP turbine 30 to the LP compressor 22. The compressor section, combustion section 26, turbine section, and nozzle section 32 together define a core air flow path 37.

[0040] For the depicted embodiment, the fan section 14 includes a fan 38 having a plurality of fan blades 40 coupled to a rotor disk 42 in a spaced-apart manner. As shown, the fan blades 40 generally extend outwardly from the rotor disk 42 in a radial direction R. The disk 42 is covered by a rotatable forward hub 48 having an aerodynamic profile to facilitate airflow through the plurality of fan blades 40. In addition, the exemplary fan section 14 includes an annular fan case or outer nacelle 50 that circumferentially surrounds the fan 38 and / or at least a portion of the turbine 16. It should be understood that the nacelle 50 can be configured to be supported relative to the core 16 by a plurality of circumferentially spaced outlet guide vanes 52. According to an exemplary embodiment, as will be described in detail below, the outlet guide vanes 52 can be mounted in the turbofan engine 10 as part of a fan frame assembly 100. Furthermore, a downstream section 54 of the nacelle 50 can extend above the exterior of the turbine 16 to define a bypass airflow passage 56 therebetween.

[0041] During operation of turbofan engine 10, a volume of air 58 enters turbofan 10 through nacelle 50 and / or associated inlet 60 of fan section 14. As this volume of air 58 passes through fan blades 40, a first portion of air 58, as indicated by arrow 62, is directed or routed into bypass airflow passage 56, while a second portion of air 58, as indicated by arrow 64, is directed or routed into core air flow path 37, or more specifically, into LP compressor 22. The ratio between first portion of air 62 and second portion of air 64 is generally referred to as the bypass ratio. The pressure of second portion of air 64 is then increased as it is directed through HP compressor 24 and into combustion section 26, where it mixes with fuel and combusts to provide combustion gases 66.

[0042] Combustion gases 66 are channeled through HP turbine 28, wherein a portion of the thermal and / or kinetic energy from combustion gases 66 is extracted via sequential stages of HP turbine stator blades 68, which are coupled to casing 18, and HP turbine rotor blades 70, which are coupled to HP shaft or spool 34, thereby causing HP shaft or spool 34 to rotate, thereby supporting operation of HP compressor 24. Combustion gases 66 are then channeled through LP turbine 30, wherein a second portion of the thermal and kinetic energy from combustion gases 66 is extracted via sequential stages of LP turbine stator blades 72, which are coupled to casing 18, and LP turbine rotor blades 74, which are coupled to LP shaft or spool 36, thereby causing LP shaft or spool 36 to rotate, thereby supporting operation of LP compressor 22 and / or rotation of fan 38.

[0043] The combustion gases 66 are then directed through the jet exhaust nozzle section 32 of the turbine 16 to provide propulsive thrust. Simultaneously, the pressure of the first portion of air 62 increases significantly as it passes through the bypass airflow passage 56 before being directed to be discharged from the nozzle exhaust section 76 of the fan 38 of the turbofan 10, also providing propulsive thrust. The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section 32 at least partially define a hot gas path 78 for directing the combustion gases 66 through the turbine 16.

[0044] However, it should be understood that Figure 1 The exemplary turbofan engine 10 depicted in FIG is merely an example, and in other exemplary embodiments, the turbofan engine 10 may have any other suitable configuration. For example, in other exemplary embodiments, the fan 38 may be configured as a variable pitch fan, including, for example, a suitable actuation assembly for rotating the plurality of fan blades about their respective pitch axes, the turbofan engine 10 may be configured as a geared turbofan engine having a reduction gearbox between the LP shaft 36 and the fan section 14, etc. It should also be understood that in other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable gas turbine engine. For example, in other exemplary embodiments, aspects of the present disclosure may be incorporated into, for example, a turboprop engine.

[0045] Now refer to Figure 2 , showing a perspective view of a fan frame assembly 100. The fan frame assembly 100 generally provides a first circular frame member or fan hub frame 102, a second circular frame member or fan case 104, and a plurality of double outlet ("doublet") guide vanes 110 arranged in a circumferential array about the hub frame 102 and the fan case 104. According to an exemplary embodiment, the fan frame assembly 100 is integrated with the turbofan engine 10 ( Figure 1 ) share a common longitudinal axis with the longitudinal axis 12 of the fan frame 10. In this manner, it will be appreciated that the fan frame assembly 100 can be used to mount the outlet guide vanes 52 into the turbofan engine 10. In this regard, the paired outlet guide vanes 110 provide a load path from the fan hub frame (and therefore the turbine 16) and the nacelle 50. While the illustrated embodiment depicts the use of dual outlet guide vanes 110, it will be appreciated that various aspects of the present subject matter may also be applied to single outlet guide vanes.

[0046] Now refer to Figure 3 , provides a perspective view of an airfoil assembly according to an exemplary aspect of the present disclosure, the airfoil assembly having a first airfoil and a second airfoil. In particular, Figure 3The airfoil assembly is configured as a double outlet guide vane 110. The double outlet guide vane 110 may be incorporated into Figure 2 The fan frame assembly 100 may be incorporated into the fan frame assembly 100, or alternatively may be incorporated into any other suitable design.

[0047] In this manner, it should be understood that the first airfoil is configured to function as a first guide vane 112 and the second airfoil is configured to function as a second guide vane 114. Each of the first guide vane 112 and the second guide vane 114 substantially defines a root end 116 and a tip end 118. The dual outlet guide vane 110 further includes a first end structure 120 spanning between the first and second guide vanes 112, 114 at the root end 116 of the dual outlet guide vane 110 and similarly includes a second end structure 122 spanning between the first and second guide vanes 112, 114 at the tip end 118. The first and second end structures 120, 122 may be used to distribute the loads experienced by the dual outlet guide vanes 110 to surrounding hardware to which they are attached, such as the fan hub frame 102 and the fan case 104 (see, e.g., FIG. 1 ). Figure 2 ).

[0048] For the depicted embodiment, the first guide vane 112 , the second guide vane 114 , the first end structure 220 , and the second end structure 222 are integrally formed together to form the dual outlet guide vane 110 .

[0049] However, it should be understood that according to alternative exemplary embodiments, first guide vane 112, second guide vane 114, first end structure 120, and second end structure 122 may be separate components that are attached together in any suitable manner to form dual outlet guide vanes 110. Alternatively, aspects of the present disclosure may still be applied to a single outlet guide vane assembly or any other suitable outlet guide vane assembly.

[0050] Still for reference Figure 4 , provides a side view of an airfoil according to an exemplary aspect of the present disclosure. More specifically, Figure 4 supply Figure 3 FIG2 is a side view of the first guide vane 112. It should be understood that the first guide vane 112 defines a spanwise direction S and a chordwise direction C, and that the spanwise direction S may be generally aligned with a radial direction of the gas turbine engine incorporating the first guide vane 112, as well as a leading edge end 124 and a trailing edge end 126. For the exemplary aspect depicted, the first guide vane 112 generally includes a body 128 that extends along the spanwise direction S between a root end 116 and a tip end 118 of the first guide vane 112. The body 128 may generally be formed of a composite material.

[0051] The term "composite material" as used herein may be defined as a material comprising reinforcements, such as fibers or particles supported in a binder or matrix material. Composite materials include metallic and non-metallic composite materials. One useful embodiment for a composite airfoil is made from a unidirectional tape material and an epoxy resin matrix. The composite airfoils disclosed herein may include a non-metallic type of composite material made from a material comprising fibers, such as carbonaceous, silica, metal, metal oxide, or ceramic fibers, embedded in a resin material such as epoxy, PMR15, BMI, PEEU, or the like. More particular materials include fibers arranged unidirectionally in a tape, the tape being impregnated with resin, formed into a part shape, and cured via an autoclave process or compression molding to form a lightweight, strong, relatively uniform article having a laminate therein. However, any suitable composite material and / or forming process may be used.

[0052] Still refer to Figure 4 As will be described in greater detail below, the first guide vane 112 further includes an edge member that is at least partially formed of a metallic material. More specifically, for the illustrated embodiment, the edge member is a leading edge member 132 that is attached to the body 128 at the leading edge end 124 of the first guide vane 112. The leading edge member 132 defines a leading edge 130 of the first guide vane 112 at the leading edge end 124 of the first guide vane 112.

[0053] More specifically, for Figure 4 In the exemplary embodiment of the present invention, the leading edge member 132 is a shaped leading edge member, and the leading edge 130 defined by the leading edge member 132 is a nonlinear patterned leading edge 130. For example, for the illustrated embodiment, the nonlinear patterned leading edge 130 of the first guide vane 112 is a wavy leading edge 130 that defines a plurality of peaks 134 arranged in a plurality of valleys 136 that are alternately arranged in the spanwise direction S.

[0054] The size, density, and number of the plurality of peaks 134 and the plurality of valleys 136 at the leading edge 130 of the first guide vane 112 can be selected, for example, to minimize noise attenuation during operation of the gas turbine engine. For example, in certain embodiments, the plurality of peaks 134 can include at least three peaks 134, such as at least four peaks 134, such as at least five peaks 134, such as up to twenty-five peaks 134, such as up to twenty peaks 134, such as up to fifteen peaks 134, such as up to ten peaks 134. There can be a similar number of valleys 136, with each valley 136 located between adjacent peaks 134.

[0055] Furthermore, for the illustrated embodiment, it will be understood that the plurality of peaks 134 includes a first peak 134A, and the plurality of valleys 136 includes a first valley 136A adjacent to the first peak 134A. The first guide vane 112 defines a first chord 138 at the first peak 134A and a second chord 140 at the first valley 136A. The first chord 138 is at least 105% of the second chord 140, such as at least 110% of the second chord 140, such as at least 115% of the second chord 140, such as at least 120% of the second chord 140, such as at least 175% of the second chord 140.

[0056] In this manner, it should be appreciated that the leading edge member 132 may be capable of reducing noise attenuation from, for example, a fan section of an engine incorporating the exemplary guide vanes.

[0057] Now refer to Figure 5 and 6 , provides a cross-sectional view of an airfoil according to the present disclosure along the span direction S of the airfoil. More specifically, for Figure 5 and 6 In an exemplary embodiment, the airfoil is Figure 4 The first guide vane 112 is shown along Figure 4 In this way, it should be understood that Figure 5 Provide along Figure 4 A cross-sectional view of the first guide vane 112 taken along line 5-5, and Figure 6 A close up cross-sectional view of the leading edge member 132 of the first guide vane 112 is provided.

[0058] As will be appreciated, the edge member includes a shell 142 formed from a metal material. Shell 142 may be referred to as an edge shell. More specifically, because the edge member is a leading edge member, shell 142 may be referred to as a leading edge shell. More specifically, because the edge member is a formed leading edge member, shell 142 may be referred to as a formed leading edge shell. Although body 128 is formed from a composite material, forming shell 142 from a metal material may better allow first guide vane 112 to accommodate foreign object impacts (such as bird strikes and ice ingestion) while minimizing damage during operation of the gas turbine engine.

[0059] To assist with this configuration, it should be understood that the shell 142 of the leading edge member 132 defines a leading edge thickness 144 and a side thickness 146. The leading edge thickness 144 can be greater than the side thickness 146. For example, the leading edge thickness 144 can be at least twice the side thickness 146, such as at least three times the side thickness 146, such as up to twenty times the side thickness 146. This can create a strong leading edge 130 that can accommodate foreign object impacts during operation. By way of example only, in certain exemplary embodiments, the side thickness 146 can be between approximately 0.001 inches and 0.2 inches, and the leading edge thickness 144 can be between approximately 0.15 inches and one inch.

[0060] Additionally, for the embodiment shown, the shell 142 of the leading edge member 132 at least partially defines an inner cavity 148. For the embodiment shown, the leading edge member 132 further includes a filler 150 positioned within the inner cavity 148. The filler 150 may be a structural filler configured to assist in maintaining the structural integrity of the leading edge member 132 in the event that the first guide vane 112 experiences a foreign object impact during operation.

[0061] As an example, in certain embodiments, filler 150 can be a foam material, a honeycomb material or both. More specifically, for the embodiment shown, filler 150 is a foam material. Foam can be a relatively low-density foam with relatively high strength and shear stiffness. For example, foam can have a density between about 15 pounds per cubic foot and about 1 pound per cubic foot. For example, foam can have a density between about 13 pounds per cubic foot and about 4 pounds per cubic foot, such as between about 12 pounds per cubic foot and about 6 pounds per cubic foot. In addition, in certain exemplary embodiments, the foam selected as filler 150 can be a relatively hard foam, which limits a shear stiffness (or rigidity modulus) greater than about 15 pounds per square foot (psi), such as greater than about 18psi, such as greater than 23psi, such as greater than or equal to about 28psi and less than about 100psi.

[0062] However, it is noted that in other exemplary embodiments, the filler material 150 may be formed of a material having a greater density, for example, a density of 80 lbs / ft3 or less, such as 70 lbs / ft3 or less. The filler material 150 may be a solid resin in this configuration.

[0063] In addition, the foam can still define a relatively low Young's modulus (also known as tensile modulus). Specifically, each foam can be formed from a material that defines a Young's modulus of less than about 125 kilopounds per square inch (Ksi). For example, the foam can be formed from a material that defines a Young's modulus of less than about 100 ksi, less than about 75 ksi, or less than about 60 ksi. In addition, the foam can be formed from a material having an elongation at break greater than about 2.5%. For example, the foam can be formed from a material having an elongation at break greater than about 3%, such as greater than about 4%, such as greater than about 8%, such as greater than about 10%. As used herein, the term "elongation at break" refers to the ratio between the length changed after the material breaks and the initial length. The term elongation at break is an indicator that measures the ability of a material to resist shape changes without cracking.

[0064] Especially refer to Figure 6 It should be understood that, in the illustrated embodiment, the filler 150 substantially completely occupies the interior cavity 148 defined by the shell 142 of the leading edge member 132. More specifically, for the illustrated embodiment, the filler 150 occupies at least approximately 90% of the interior cavity 148 defined by the shell 142 of the leading edge member 132, such as at least approximately 95% of the interior cavity 148, such as at least approximately 98% of the interior cavity 148, such as at least approximately 99% of the interior cavity 148.

[0065] However, it should be understood that in other exemplary embodiments, the leading edge member 132 of the first guide vane 112 may not include the filler 150 to substantially completely occupy the inner cavity 148 defined by the shell 142 of the leading edge member 132. For example, referring briefly to Figure 7 , provides a close-up schematic view of a leading edge member 132 of an airfoil according to another exemplary embodiment of the present disclosure. Figure 7 The leading edge member 132 may be Figure 6 The exemplary leading edge members 132 of the guide vanes are configured in substantially the same manner. For example, Figure 7 The leading edge member 132 may generally include a shell 142 that at least partially defines an inner cavity 148. However, for the illustrated embodiment, the leading edge member 132 does not include filler material 150 that substantially completely occupies the inner cavity 148. Instead, the filler material 150 of the leading edge member 132 occupies between approximately 20% and approximately 90% of the inner cavity 148, such as at least 50% of the inner cavity 148. For example, Figure 7As shown in the embodiment of FIG, in certain exemplary embodiments, the filler 150 may occupy only the front portion of the leading edge member 132, such as the front 20% of the inner cavity 148, such as the front 30% of the inner cavity 148, such as the front 40% of the inner cavity 148, such as the front 50% of the inner cavity 148 (each portion calculated by total volume). In this way, the filler 150 can provide structural support to the leading edge member 132 at a location that is most susceptible to damage from foreign object impact during operation. For example, the filler 150 may occupy the portion of the inner cavity 148 within the peak 134 of the leading edge member 132.

[0066] Reference Figure 5 and 6 It will be further understood that the body 128 defines an inner body cavity 152. The inner body cavity 152 may extend along at least 50% of the body 128 and the chord direction C (see FIG. Figure 5 The body inner cavity 152 may include a body filler 154 that substantially completely occupies the body inner cavity 152. The body filler 154 may be the same material as the filler 150 used for the leading edge member 132, or alternatively, may be any other suitable filler, such as any other suitable filler that meets the specifications described above with respect to the filler 150 of the leading edge member 132.

[0067] In addition, still refer to Figure 6 It should be understood that the leading edge member 132 may be coupled to the guide vane body 128 in any suitable manner. For example, in certain exemplary embodiments, the leading edge member 132 may be coupled to the guide vane body 128 using one or more of adhesives, mechanical fasteners, complementary geometric shapes, and the like.

[0068] More specifically, now also refer to Figure 8 , provides a close-up view of the joint between the main body 128 and the leading edge member 132, it being understood that the leading edge member 132 is bonded to the main body 128. For the illustrated embodiment, the shell 142 includes a pressure side portion 156 and a suction side portion 158. The pressure side portion 156 and the suction side portion 158 of the shell 142 each include an overlapping section that is configured to overlap with the main body 128 of the guide vane. The overlapping sections of the pressure side portion 156 of the shell 142 and the suction side portion 158 of the shell 142 are each tapered such that an end thickness 160 at the end of each overlapping section is substantially less than a side thickness 146 of the shell 142 defining the inner cavity 148. For example, the side thickness 146 may be at least twice the end thickness 160, such as at least three times the end thickness 160, such as up to 200 times the end thickness 160.

[0069] Similarly, for the illustrated embodiment, the body 128 is configured to taper at an end adjacent to the leading edge member 132, wherein overlapping portions of the pressure side portion 156 and the suction side portion 158 of the casing 142 overlap the body 128. For example, the body 128 defines a first thickness 162 at a location spaced apart from the leading edge member 132, and a second thickness 164 at an end adjacent to the leading edge member 132. The second thickness 164 is less than the first thickness 162. For example, the second thickness 164 may be approximately 95% or less of the first thickness 162, such as 90% or less of the first thickness 162, 85% or less of the first thickness 162, or 75% or less of the first thickness 162, as well as at least 10% of the first thickness, such as at least 25% of the first thickness 162, such as at least 50% of the first thickness 162.

[0070] Additionally, for the illustrated embodiment, the leading edge member 132 further includes an intermediate layer 166. The leading edge member 132 is at least partially bonded to the body 128 via the intermediate layer 166. More specifically, it will be appreciated that for the illustrated embodiment, the intermediate layer 166 may be configured as a fiber layer applied over at least a portion of the filler 150 and over at least a portion of the body 128. With this configuration, the shell 142 of the leading edge member 132 may be bonded to the fiber layer, and the fiber layer, in turn, may be bonded to the body 128 using, for example, a resin or any other suitable bonding method for bonding composite materials.

[0071] In the exemplary embodiment shown, the intermediate layer 166 is applied over an overlapping portion 168 of the main body 128 of the first guide vane 112. The overlapping portion 168 of the main body 128 of the airfoil defines a length 170 in the chord-wise direction C. Furthermore, it should be understood that the first guide vane 112 defines a chord 172 at the spanwise location of the overlapping portion 168 (see FIG. Figure 5 The length of overlap 168 is equal to at least 5% of the chord 172 of first guide vane 112 at the spanwise location of overlap 168. For example, the length of overlap 168 may be equal to at least 10% of the chord 172, such as up to approximately 30% of the chord 172.

[0072] In certain embodiments, the intermediate layer 166 may be a prepreg layer (ie, a layer of composite fiber material "pre-impregnated" with a polymer matrix material, such as epoxy or phenolic resin, or even a thermoplastic material), such as a carbon fiber prepreg layer.

[0073] Furthermore, with respect to bonding the housing 142 to the intermediate layer 166, for example, the housing 142 of the leading edge member 132 may be formed by an electroforming process. As used herein, the term "electroforming" generally refers to a metal forming process in which a component is manufactured by electrodepositing metal onto a conductive material.

[0074] In this manner, it should be understood that filler 150 can be a non-conductive filler. Therefore, in order to utilize the electroforming process, a conductive coating may need to be applied to filler 150. Specifically, for the depicted embodiment, filler 150 is a non-conductive filler, and intermediate layer 166 is a conductive intermediate layer. For example, intermediate layer 166 can be a conductive layer, such as a carbon fiber prepreg layer as described above. The shell 142 of the leading edge member 132 can then be formed over the conductive coating via the electroforming process. In this manner, the shell 142 can be formed over and bonded to the intermediate layer 166.

[0075] As described above, the intermediate layer 166 functions as a conductive coating and may be further at least partially coated over the body 128 of the first guide vane 112 such that the shell 142 may be further formed over the body 128 of the first guide vane 112 to bond the leading edge member 132 to the body 128 of the first guide vane 112. More specifically, it should be understood that for Figure 7 In an exemplary embodiment of the present invention, intermediate layer 166 includes a portion 174 that extends over body 128 and past the end of housing 142. Portion 174 extending over body 128 and past the end of housing 142 may be more fully bonded to body 128 because it may not be necessary for the conductive properties of portion 174 to be exposed in order to form housing 142 via an electroforming process.

[0076] Forming the leading edge member 132 according to such exemplary aspects may allow for the inclusion of the metal leading edge member 132 on an otherwise composite airfoil without requiring mechanical fasteners or other structurally obstructive or intrusive mechanisms to facilitate attachment.

[0077] However, it should be understood that the above exemplary embodiments are provided by way of example only. In other exemplary embodiments, any other suitable configurations may be provided. For example, although Figure 3-8 While exemplary embodiments of the present disclosure are discussed with reference to guide vanes (such as the first guide vane 112), in other exemplary embodiments, the guide vanes may be replaced with any other suitable airfoil of the engine. For example, in other embodiments, aspects of the present disclosure may be applied to rotating airfoils, such as fan blades or rotor blades, any other suitable stationary airfoil, or guide vanes, etc.

[0078] Furthermore, it should be understood that although the leading edge member 132 is described above as the leading edge member 132, as well as other exemplary aspects of the present disclosure, the concepts described herein may be applied to any other suitable edge member of an airfoil, for example, to attach the edge member to the airfoil body 128. For example, in other exemplary embodiments, the concepts described herein may be applied to non-leading edge members, such as a trailing edge member, to bond the edge member to the airfoil body 128.

[0079] Furthermore, although aspects of the present disclosure describe structures formed in a particular manner, in other exemplary embodiments, the structures may be formed in any other suitable manner, such as by any other suitable forming process, attachment process, etc.

[0080] Furthermore, it should be understood that in other exemplary embodiments, the leading edge member 132 may be coupled to the guide vane body 128 in any suitable manner. For example, in certain exemplary embodiments, the leading edge member 132 may include or be formed from metal that is directly coupled to the airfoil body 128, such as the metal shell 142.

[0081] Furthermore, it should be understood that while the filler material 150 positioned within the inner cavity 148 is configured as a solid foam material in at least some embodiments, other suitable configurations may be provided in other embodiments. For example, referring now briefly to Figure 9 It should be understood that in other exemplary embodiments, the filler material 150 may include a first material 176 and a second material 178, wherein the second material 178 is completely enclosed within the first material 176 and serves as a reinforcement member for the filler material 150. For example, the first material 176 may be foam, and the second material 178 may be a metal or other relatively hard material positioned within the foam to increase the stiffness / strength of the foam. For the illustrated embodiment, the second material 178 is arranged as a truss extending in a longitudinal direction (e.g., radially when incorporated into an engine) through the first material 176. Other configurations are also contemplated.

[0082] Now refer to Figure 10 , a flow chart of a method 200 of forming an airfoil according to an exemplary aspect of the present disclosure is provided. In certain exemplary aspects, Figure 8 The method 200 may be used with one or more of the exemplary airfoils and / or guide vanes described above having Figure 1-7 However, other exemplary aspects, Figure 10 The method 200 may be used with any other suitable airfoils and / or guide vanes.

[0083] For the depicted exemplary aspects, method 200 includes adding a conductive layer to a filler for an edge member of an airfoil at (202). In certain exemplary aspects, adding the conductive layer to the filler at (202) includes adding a carbon composite layer, such as a carbon fiber prepreg layer, over the filler at (204). Furthermore, in certain exemplary aspects, adding the conductive layer to the filler at (202) includes adding the conductive layer over the filler and over a portion of the body of the airfoil at (206). For example, adding the conductive layer over the filler and over a portion of the body of the airfoil at (206) includes adding the conductive layer over an overlapping portion of the body of the airfoil at (207), wherein the overlapping portion of the body of the airfoil defines a length in a chordwise direction that is equal to at least 5% of the chord of the airfoil at a spanwise location of the overlapping portion. For example, the length of the overlapping portion can be equal to at least 10% of the chord of the airfoil at a radial location, such as up to about 30% of the chord of the airfoil at a radial location.

[0084] Still refer to Figure 10 The method 200 further includes electroforming an edge shell over the filler at (208), the edge shell being formed of a metallic material. More specifically, for the exemplary aspect shown, electroforming the edge shell over the filler at (208) includes electroforming the edge shell over the filler and over a portion of the body of the airfoil at (210) to bond the edge shell to the body of the airfoil. More specifically, for the exemplary aspect shown, electroforming the edge shell over the filler at (208) includes electroforming the edge shell over a conductive layer added over the filler of the edge member and over an overlapping portion of the body of the airfoil at (211).

[0085] Furthermore, for the exemplary aspect of the depicted method 200, the method 200 further includes bonding the conductive layer to the body of the airfoil at (212). Bonding the conductive layer to the body of the airfoil at (212) may occur before electroforming the edge shell over the filler at (208), after electroforming the edge shell over the filler at (208), or both. Furthermore, bonding the conductive layer to the body of the airfoil at (212) may include bonding the conductive layer to the body of the airfoil using, for example, an epoxy or other adhesive material. Furthermore, bonding the conductive layer to the body of the airfoil at (212) may include bonding a portion of the conductive layer that extends over the body of the airfoil through the edge shell to the body of the airfoil.

[0086] The edge member may be a leading edge member, such as a shaped leading edge member.

[0087] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[0088] Other aspects are provided by the following topics:

[0089] An airfoil for a gas turbine engine, the airfoil defining a spanwise direction, a root end, a tip end, a leading edge end, and a trailing edge end, the airfoil comprising: a body extending in the spanwise direction between the root end and the tip end, the body being formed of a composite material; and a formed leading edge member attached to the body, the formed leading edge member being positioned at the leading edge end of the airfoil, the formed leading edge member being at least partially formed of a metallic material and defining a nonlinear patterned leading edge of the airfoil.

[0090] An airfoil according to one or more of these clauses, wherein the formed leading edge member includes a leading edge shell formed from a metallic material, wherein the leading edge shell at least partially defines a leading edge inner cavity, and wherein the formed leading edge member further includes a filler positioned within the leading edge inner cavity.

[0091] An airfoil according to one or more of these clauses, wherein the filler is a foam material, a honeycomb material, or both.

[0092] The airfoil according to one or more of these clauses, wherein the filler defines a density less than 80 pounds per cubic foot.

[0093] The airfoil according to one or more of these clauses, wherein the filler is a non-conductive material.

[0094] The airfoil according to one or more of these clauses, wherein the shaped leading edge member further comprises a conductive layer between the filler and the leading edge shell.

[0095] An airfoil according to one or more of these clauses, wherein the filler occupies at least 95% of the leading edge inner cavity.

[0096] An airfoil according to one or more of these clauses, wherein the shaped leading edge member further comprises an intermediate layer between the filler and the leading edge shell, wherein the intermediate layer extends at least partially over the main body, wherein the intermediate layer is bonded to the main body, and wherein the leading edge shell is bonded to the intermediate layer.

[0097] An airfoil according to one or more of these clauses, wherein the shaped leading edge member forms at least 20% of the airfoil in a chordwise direction at a spanwise location of the airfoil.

[0098] An airfoil according to one or more of these clauses, wherein the non-linear patterned leading edge of the airfoil is a wavy leading edge of the airfoil.

[0099] An airfoil according to one or more of these clauses, wherein the nonlinear patterned leading edge of the airfoil defines a plurality of peaks and a plurality of valleys, the plurality of peaks including a first peak and the plurality of valleys including the first valley, and wherein the airfoil defines a first chord at the first peak and a second chord at the second peak, wherein the first chord is at least 110% of the second chord.

[0100] An airfoil according to one or more of these clauses, wherein the airfoil is an outlet guide vane for a gas turbine engine.

[0101] A method of forming an airfoil includes adding a conductive layer to a filler for an edge member of the airfoil; and electroforming an edge shell over the filler, the edge shell being formed of a metallic material.

[0102] The method of one or more of these clauses, wherein adding the conductive layer to the filler comprises adding the conductive layer over the filler and over a portion of a body of the airfoil, wherein the body is formed of a composite material.

[0103] The method of one or more of these clauses, wherein electroforming the edge shell over the filler comprises electroforming an edge shell over the filler and over a portion of the main body of the airfoil to bond the edge member to the main body of the airfoil.

[0104] The method of one or more of these clauses, wherein adding the conductive layer to the filler comprises adding a carbon composite layer over the filler.

[0105] The method according to one or more of these clauses, wherein the filler is a non-conductive material.

[0106] The method according to one or more of these clauses, wherein the edge member is a leading edge member, the leading edge member defining a non-linear patterned leading edge of the airfoil.

[0107] An airfoil for a gas turbine engine, the airfoil defining a span direction, a root end, and a tip end, the airfoil comprising: a main body extending in the span direction between the root end and the tip end, the main body being formed of a composite material; and an edge member comprising an edge shell formed of a metallic material and at least partially defining an inner cavity; a filler positioned in the inner cavity; and an intermediate layer between the filler and the edge shell and extending at least partially over the main body, wherein the intermediate layer is bonded to the main body, and the edge shell is bonded to the intermediate layer.

[0108] The airfoil according to one or more of these clauses, wherein the filler is a non-conductive material, wherein the intermediate layer is a conductive layer, and wherein the edge shell is formed onto the intermediate layer by an electroforming process to bond the edge shell to the intermediate layer.

Claims

1. An airfoil for a gas turbine engine, the airfoil defining a spanwise direction, a root end, a tip end, a leading edge end, and a trailing edge end, wherein: The airfoil comprises: a main body extending in the span direction between the root end and the tip end, the main body being formed of a composite material; and a formed leading edge member attached to the body, the formed leading edge member positioned at the leading edge end of the airfoil, the formed leading edge member being formed at least in part of a metallic material and defining a nonlinear patterned leading edge of the airfoil, the formed leading edge member including a leading edge shell formed of the metallic material, the leading edge shell defining a leading edge inner cavity, and the formed leading edge member further including a filler completely enclosed within the leading edge inner cavity, the filler further including a first material and a second material, the second material completely enclosed within the first material, wherein the first material is a foam and the second material is a hard material.

2. The airfoil according to claim 1, wherein: The filler defines a density of less than 80 pounds per cubic foot.

3. The airfoil according to claim 1, wherein: The filler is a non-conductive material.

4. The airfoil according to claim 3, wherein: The shaped leading edge member further includes a conductive layer between the filler and the leading edge shell.

5. The airfoil according to claim 1, wherein: The filler occupies at least 95% of the leading edge inner cavity.

6. The airfoil according to claim 1, wherein: The shaped leading edge member further includes an intermediate layer between the filler and the leading edge shell, wherein the intermediate layer extends at least partially over the main body, wherein the intermediate layer is bonded to the main body, and wherein the leading edge shell is bonded to the intermediate layer.

7. The airfoil according to claim 1, wherein: The shaped leading edge member forms at least 20% of the airfoil in a chordwise direction at a spanwise location of the airfoil.

8. The airfoil according to claim 1, wherein: The nonlinear patterned leading edge of the airfoil is a wavy leading edge of the airfoil.

9. The airfoil according to claim 1, wherein: in, The nonlinear patterned leading edge of the airfoil defines a plurality of peaks and a plurality of valleys, the plurality of peaks including a first peak and a second peak, the plurality of valleys including a first valley, and wherein the airfoil defines a first chord at the first peak and a second chord at the second peak, wherein the first chord is at least 110% of the second chord.

10. The airfoil according to claim 1, wherein: The airfoil is an outlet guide vane for the gas turbine engine.

11. A method of forming an airfoil, characterized in that: The method comprises: adding a conductive layer to a filler for an edge member of the airfoil; and electroforming an edge shell on the filler, the edge shell being formed of a metal material; adding the conductive layer to the filler includes adding the conductive layer over the filler and over a portion of a body of the airfoil, wherein the body is formed of a composite material; and Electroforming the edge shell on the filler includes electroforming the edge shell on the filler and on the portion of the main body of the airfoil to bond the edge member to the main body of the airfoil.

12. The method according to claim 11, characterized in that Adding the conductive layer to the filler includes adding a carbon composite layer on the filler.

13. The method according to claim 11, characterized in that The filler is a non-conductive material.

14. The method according to claim 11, characterized in that The edge member is a leading edge member that defines a nonlinear patterned leading edge of the airfoil.

15. An airfoil for a gas turbine engine, characterized in that The airfoil defines a span direction, a root end, and a tip end, and the airfoil includes: a main body extending in the span direction between the root end and the tip end, the main body being formed of a composite material; and an edge member comprising an edge housing formed of a metallic material and at least partially defining an inner cavity; a filler material surrounded by the inner cavity, wherein the filler material is a foam material, a honeycomb material, or both; and An intermediate layer is between the filler and the edge shell and extends at least partially over the body, wherein the intermediate layer is bonded to the body and the edge shell is bonded to the intermediate layer.

16. The airfoil according to claim 15, wherein: The filler is a non-conductive material, wherein the intermediate layer is a conductive layer, and wherein the edge housing is formed onto the intermediate layer by an electroforming process to bond the edge housing to the intermediate layer.

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