Patent Application
20080072569
Fan assembly 12 includes an array of fan blades 24 extending radially outward from a rotor disk 26. Gas turbine engine assembly 10 has an intake side 28 and an exhaust side 30. Fan assembly 12, booster 22, and turbine 20 are coupled together by a first rotor shaft 31, and compressor 14 and turbine 18 are coupled together by a second rotor shaft 32.
In operation, air flows through fan assembly 12 and a first portion of the airflow is channeled through booster 22. The compressed air that is discharged from booster 22 is channeled through compressor 14 wherein the airflow is further compressed and delivered to combustor 16. Hot products of combustion (not shown in
A second portion of the airflow discharged from fan assembly 12 is channeled through a bypass duct 40 to bypass a portion of the airflow from fan assembly 12 around core gas turbine engine 13. More specifically, bypass duct 40 extends between a fan casing or shroud 42 and splitter 44. Accordingly, a first portion 50 of the airflow from fan assembly 12 is channeled through booster 22 and then into compressor 14 as described above, and a second portion 52 of the airflow from fan assembly 12 is channeled through bypass duct 40 to provide thrust for an aircraft, for example. Gas turbine engine assembly 10 also includes a fan frame assembly 60 to provide structural support for fan assembly 12 and is also utilized to coupled fan assembly 12 to core gas turbine engine 13.
Fan frame assembly 60 is one of various frame and support assemblies of gas turbine engine assembly 10 that are used to facilitate maintaining an orientation of various components within gas turbine engine assembly 10. More specifically, such frame and support assemblies interconnect stationary components and provide rotor bearing supports. Fan frame assembly 60 is coupled downstream from fan assembly 12 within bypass duct 40 such that outlet guide vanes 62 and struts 68 are circumferentially-spaced around the outlet of fan assembly 12 and extend across the airflow path discharged from fan assembly 12.
Airfoil 102 includes a first sidewall 110 and a second sidewall 112. In one embodiment, either first and/or second sidewalls 110 and/or 112 may be contoured to improve aerodynamic performance. In the exemplary embodiment, first sidewall 110 is convex and defines a suction side of airfoil 102, and second sidewall 112 is concave and defines a pressure side of airfoil 102. Sidewalls 110 and 112 are joined at a leading edge 114 and at an axially-spaced trailing edge 116 of airfoil 102. More specifically, airfoil trailing edge 116 is spaced chordwise and downstream from airfoil leading edge 114. First and second sidewalls 110 and 112, respectively, extend longitudinally or radially outward in span from radially inner flange 106 to radially outer flange 104. In the exemplary embodiment, at least a portion of outlet guide vane 100 is fabricated utilizing a metallic material such as, but not limited to, titanium, aluminum, and/or a Metal Matrix Composite (MMC) material.
As shown in
In the exemplary embodiment, first and/or second pockets 140 and/or 142 are each sized to receive a respective filler 150 and/or 151 therein that is a relatively lightweight material. Lightweight material as used herein, is defined as a material that is different than the material utilized to fabricate leading edge portion 130, trailing edge portion 132, and connecting member 134, are fabricated utilizing a material that has a per volume weight that is greater than the per volume weight of the filler material. In the exemplary embodiment, each filler 150 and 151 are fabricated from a Styrofoam, for example. As such, each pocket 140 and 142 has a depth 144 and each respective filler 150 and 151 has a thickness 152 that is substantially equal to the pocket depth 144 such that when each respective filler 150 and 151 are positioned within pockets 140 and/or 142, airfoil 102 has an aerodynamic profile that is substantially smooth from the airfoil leading edge 114 to the airfoil trailing edge 116. That is, the fillers 150 and 151 are each substantially flush with the outer surfaces of both leading edge portion 130 and/or trailing edge portion 132 when positioned within a respective pocket 140 and 142. In one embodiment, fillers 150 and 151 are fabricated as separate components and installed within pockets 140 and 142. Optionally, fillers 150 and 151 are sprayed or injected into pockets 140 and 142 and machined to form a relatively smooth or aerodynamic outer surface to which a covering material is attached, as discussed below.
As such to fabricate outlet guide vane 100, the vane is cast or forged to include the leading edge portion 130, trailing edge portion 132, and connecting member 134, and the inner and outer flange 104 and 106. The fillers 150 and 151 are then injected or coupled within the pockets 140 and 142 as described above. A covering material 170 is then wrapped around the outer periphery of airfoil 102 to substantially encapsulate leading edge portion 130, trailing edge portion 132, and fillers 150 and 151. For example, covering material 170 may be wrapped at a forty-five degree angle completely around airfoil 102 in successive rows or layers. Moreover, the covering material 170 facilitates increasing the overall structural integrity of outlet guide vane 100 and forms a relatively smooth outer surface to improve aerodynamic performance.
In the exemplary embodiment, covering material 170 is a composite material that is bonded to the leading edge portion 130, trailing edge portion 132, and connecting member 134, and the inner and outer flange 104 and 106 utilizing a thermoset material, for example. In the exemplary embodiment, the covering material may be a fiberglass material, a graphite material, a carbon material, a ceramic material, an aromatic polyamid material such as KEVLAR, a thin metallic material, and/or mixtures thereof. Any suitable thermosetting polymeric resin can be used in forming covering material 170, for example, vinyl ester resin, polyester resins, acrylic resins, epoxy resins, polyurethane resins, bismalimide resin, and mixtures thereof. Overall, the covering material 170 is selected such that an exterior surface of outlet guide vane is resistant to wear and or damage that may be caused by foreign objects ingested into gas turbine engine assembly 10.
Described herein is a gas turbine engine wherein at least some known outlet guide vanes are replaced with an outlet guide vane having a substantially hollow interior portion filled with a relatively lightweight material and then wrapped with a composite material to form a lightweight outlet guide vane. As such, the exemplary outlet guide vanes described herein reduce the overall weight of the gas turbine engine assembly while still maintaining structural integrity thus achieving the very challenging engine weight goals for new applications. The method of fabricating the outlet guide vanes includes fabricating an airfoil that includes a leading edge portion and a trailing edge portion each fabricated from a first material, and installing a filler portion between the leading and trailing edge portions, the filler portion is fabricated from a second material that is lighter than the first material.
More specifically, the outlet guide vanes described herein includes two spars that form the airfoil portion of the outlet guide vane. The area between the spars is filled with a lightweight material such as Styrofoam to add rigidity to the airfoil, and then wrapped with a composite material. In one embodiment, the airfoil includes two spars connected by a thin web member to provide radial and axial overturning stiffness. Moreover, the connecting member also provides additional strength to the airfoil shape to protect against any Aero Mechanical vibrations. Optionally, the airfoil does not include the connecting member.
In one embodiment, the spars are substantially solid. Optionally, a portion of the interior of each spar may be removed to further reduce the overall weight of the outlet guide vane. The outlet guide vane is then covered utilizing a thin metallic material or a composite material to protect the outlet guide vane from solid particle damage. In one embodiment, the spars are fabricated using a metallic material. Optionally, the spars may be fabricated utilizing a composite material that includes a plurality of fibers woven directionally radial to the gas turbine engine axis 11.
As a result, the outlet guide vanes described herein substantially reduce the overall weight of the gas turbine engine assembly. For example, the outlet guide vanes described herein are 30% to 50% lighter than known outlet guide vanes.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
