Patent Grant
11441545
The present disclosure relates in general to rotor blades, and more particularly to tungsten-based leading edge protection caps for rotor blades to protect the rotor blades from erosion and/or corrosion.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
During the operation of a wind turbine, the rotor blades may be subjected to a wide variety of environmental conditions. In many cases, such as when the wind turbines are located in coastal or desert areas or offshore, the rotor blades may be subjected to environmental conditions that include abrasive materials, such as sand particles, rain droplets, or seawater. The interaction of these abrasive materials with the rotor blades may cause portions of the rotor blades to erode. In particular, the leading edges of rotor blades may be highly susceptible to erosion. Erosion of the various portions of the rotor blades limits the maximum rotational speed of the rotor blades, thus limiting the power output of the wind turbine. More particularly, leading edge erosion can lead to the loss of surface roughness and/or chord loss, thereby resulting in performance loss and durability issues overtime.
Thus, an improved protection cap for a rotor blade that prevents erosion and/or corrosion would be welcomed in the art. In view of the foregoing, the present disclosure is directed to a tungsten-based metallic leading edge cap for wind turbine rotor blades that protects the blades from erosion.
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.
In one aspect, the present disclosure is directed to a rotor blade assembly. The rotor blade assembly includes at least one rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. The surfaces are constructed of a polymeric composite material. The rotor blade assembly also includes a protection cap arranged adjacent to one or more of the surfaces of the rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade. The protection cap includes a body defining an overall length. Further, at least a first segment of the protection cap is constructed of tungsten-based metal. Thus, the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.
In an embodiment, the tungsten-based metal may be, for example, elemental tungsten, tungsten titanium, tungsten silicon, tungsten nickel, or tungsten aluminum. Further, in an embodiment, the protection cap may cover at least a portion of the leading edge of the rotor blade. In another embodiment, the tungsten-based metal may be formed into at least one of foil, one or more strips, one or more plates, or one or more sheets.
In particular embodiments, the protection cap may be secured to the one or more of the surfaces via an adhesive.
In further embodiments, the protection cap may have a clip-on spring configuration that clips onto the one or more of the surfaces of the rotor blade. In such embodiments, a thickness of a cross-section of the clip-on spring configuration varies along at least a portion of the overall length of the protection cap. In additional embodiments, the clip-on spring configuration may also include at least one of internal thickened edges or external thickened edges.
In alternative embodiments, the protection cap may have a clip-in configuration that is secured at least partially within an inner cavity of the rotor blade. In such embodiments, the clip-in configuration may include a protruding leading edge portion and opposing flanges. More particularly, in an embodiment, the opposing flanges may be secured to an inner surface of the one or more of the surfaces of the rotor blade within the inner cavity of the rotor blade.
In several embodiments, at least a second segment of the protection cap may be constructed of a polymeric material.
In yet another embodiment, the protection cap may be integrated with a lightning protection system of the rotor blade.
In another aspect, the present disclosure is directed to a method for manufacturing a rotor blade assembly. The method includes providing at least one rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. Further, the surfaces are constructed of a polymeric composite material. The method also includes forming a protection cap having a shape that corresponds to a curvature of one or more of the surfaces of the rotor blade. A first segment of the protection cap is formed of a tungsten-based metal and a second segment of the protection cap is formed of a different material. Further, the method includes arranging the protection cap adjacent to one or more of the surfaces of the rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade. Moreover, the method includes securing the protection cap to the one or more of the surfaces of the rotor blade such that the first segment of the protection cap being formed of the tungsten-based metal is arranged adjacent to the blade tip. Thus, the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.
In an embodiment, forming the protection cap may include at least one of sheet press-forming, laser sheet forming, additive manufacturing, electroforming, cold spraying, rolling, surface hardening, coating deposition, sintering, or similar, as well as combinations thereof.
In another embodiment, the tungsten-based metal may include, for example, elemental tungsten, tungsten titanium, tungsten silicon, tungsten nickel, or tungsten aluminum, whereas the different material may include a polymeric material, a shape memory alloy, a nickel alloy (such as nickel chromium or nickel chromium molybdenum, as examples), an aluminum alloy, a titanium alloy, a steel alloy, or any other suitable material.
In further embodiments, securing the protection cap to the one or more of the surfaces of the rotor blade may include securing the protection cap to the one or more of the surfaces of the rotor blade via at least one of adhesive or mechanical engagement. For example, in an embodiment, the mechanical engagement may include a clip-on spring configuration, a clip-in configuration, or one or more fasteners.
Thus, wherein the mechanical engagement is the clip-on configuration, the method may include forming a thickness of a cross-section of the clip-on spring configuration to vary along at least a portion of the overall length of the protection cap via additive manufacturing, electroforming, cold spraying, or combinations thereof.
In additional embodiments, the method may also include forming at least one additional feature onto the protection cap via at least one of additive manufacturing, electroforming, cold spraying, rolling, surface hardening, or similar, as well as combinations thereof. In such embodiments, the additional feature(s) may include internal thickened edges, external thickened edges, one or more flanges, an aerodynamic surface feature, or any other suitable feature.
In another embodiment, the clip-in configuration may include a protruding leading edge portion and opposing flanges. In such embodiments, the method may include forming the leading edge portion of a first material and the opposing flanges of a second material, with the first and second materials being different and securing the opposing flanges to an inner surface of the one or more of the surfaces of the rotor blade within the inner cavity of the rotor blade.
In still further embodiments, the method may include integrating the protection cap with a lightning protection system of the rotor blade, e.g. via a rivet or bolt. It should be understood that the rotor blade may further include any of the additional features described herein.
In yet another aspect, the present disclosure is directed to a protection cap for arranging adjacent to one or more surfaces of a rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade. The protection cap includes a body defining an overall length with at least a first segment of the protection cap constructed of elemental tungsten. Further, the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.
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 invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Referring now to the drawings,
Referring now to
Moreover, the rotor blade 16 may, in exemplary embodiments, be curved. Curving of the rotor blade 16 may entail bending the rotor blade 16 in a generally flapwise direction and/or in a generally edgewise direction. The flapwise direction may generally be construed as the direction (or the opposite direction) in which the aerodynamic lift acts on the rotor blade 16. The edgewise direction is generally perpendicular to the flapwise direction. Flapwise curvature of the rotor blade 16 is also known as pre-bend, while edgewise curvature is also known as sweep. Thus, a curved rotor blade 16 may be pre-bent and/or swept. Curving may enable the rotor blade 16 to better withstand flapwise and edgewise loads during operation of the wind turbine 10 and may further provide clearance for the rotor blade 16 from the tower 12 during operation of the wind turbine 10.
The rotor blade 16 may generally be formed of a polymeric composite material, such as an optionally reinforced thermoset or thermoplastic material. Thermoset materials generally encompass a plastic material or polymer that is non-reversible in nature. For example, thermoset materials, once cured, cannot be easily remolded or returned to a liquid state. As such, after initial forming, thermoset materials are generally resistant to heat, corrosion, and/or creep. Example thermoset materials as described herein may generally include, but are not limited to, some polyesters, some polyurethanes, esters, epoxies, or any other suitable thermoset material.
In contrast, thermoplastics generally encompass a plastic material or polymer that is reversible in nature. For example, thermoplastic materials typically become pliable or moldable when heated to a certain temperature and returns to a more rigid state upon cooling. Further, thermoplastic materials may include amorphous thermoplastic materials and/or semi-crystalline thermoplastic materials. For example, some amorphous thermoplastic materials may generally include, but are not limited to, styrenes, vinyls, cellulosics, polyesters, acrylics, polysulphones, and/or imides. More specifically, exemplary amorphous thermoplastic materials may include polystyrene, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), glycolised polyethylene terephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphous polyamide, polyvinyl chlorides (PVC), polyvinylidene chloride, polyurethane, or any other suitable amorphous thermoplastic material. In addition, exemplary semi-crystalline thermoplastic materials may generally include, but are not limited to polyolefins, polyamides, fluropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and/or acetals. More specifically, exemplary semi-crystalline thermoplastic materials may include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene, polyamide (nylon), polyetherketone, or any other suitable semi-crystalline thermoplastic material.
As illustrated in
In further embodiments, the protection cap 110 may be configured on only a portion of the rotor blade 16 along the length of the rotor blade in the generally span-wise direction. For example, the protection cap 110 may be configured on approximately the outer half of the length of the rotor blade 16 or, in exemplary embodiments, approximately the outer third of the length of the rotor blade 16 (in other words, the approximate half or third of the length of the rotor blade 16 that includes the tip 32). Thus, the protection cap 110 may extend in the generally span-wise direction along substantially the entire outer half of the rotor blade 16, or along substantially the entire outer third of the rotor blade 16.
However, it should be understood that the present disclosure is not limited to the protection cap 110 being configured on or extending through only a certain portion of the spanwise or chordwise length of the rotor blade 16. Rather, any configuration of the protection cap 110 on any portion of the length of the rotor blade 16 is within the scope of the present disclosure.
Moreover, the protection cap 110 may be formed of a single piece of material or constructed of a plurality of segments. For example, as shown in
Pure elemental tungsten is also highly resistant to corrosion, such as those found in sea environments. For example, pure elemental tungsten is generally inert to general chemical environments including oxygen at room temperature and its reactivity increases with increase in temperature. Thus, in sea environments (which are usually acidic), pure elemental tungsten can be more resistant to corrosion than other alkaline mediums. Furthermore, where pure elemental tungsten is used without any other element, high corrosion-resistance is maintained as corrosion-resistance reduces in the presence of binder phases (including attack on intergranular boundaries of different phases).
This combination of erosion and corrosion resistance is unique. On the other hand, cermet materials, such as tungsten carbide (in sintered or coated form) are prone to droplet erosion and/or corrosion damage due to the presence of carbide binder interfaces which become sites for erosion and/or corrosion damage.
Further, the tungsten-based metal may be formed into any suitable shape having any suitable thickness. For example, in an embodiment, the tungsten-based metal described herein may be formed into one or more foil sheets of material. In another embodiment, the tungsten-based metal may formed into one or more strips. In still another embodiment, the tungsten-based metal may be formed into one or more plates or one or more sheets.
In another embodiment, the second segment(s) 116, where applicable, may be constructed of a different material, such as a polymeric material, a nickel alloy (such as nickel chromium or nickel chromium molybdenum, as examples), an aluminum alloy, a titanium alloy, a steel alloy, or any other suitable material.
In particular embodiments, the protection cap 110 may be secured to the rotor blade surface(s) using any suitable means, such via an adhesive, mechanical engagement, or one or more fasteners, and/or combinations thereof. Further, as shown in
In additional embodiments, the clip-on spring configuration may also include at least one of internal thickened edges or external thickened edges. For example, as shown in
In alternative embodiments, as shown in
In addition, the leading edge portion 124 and the opposing flanges 126, 128 may be formed of any suitable material(s). In one embodiment, the leading edge portion 124 and the opposing flanges 126, 128 may be formed of the same material. Alternatively, in another embodiment, the leading edge portion 124 may be formed of a first material and the opposing flanges 126, 128 may be formed of a second material, with the first and second materials being different. In such embodiments, an electroforming process may be used to form the protection cap 110 of differing materials.
Referring back to
Thus, the protection cap 110 may be fastened or otherwise secured to the rotor blade 16 through the lightning receptor(s) 136 (e.g. via one or more rivets). Accordingly, as shown in
Still referring to
Referring now to
As shown at (202), the method 200 includes providing a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. As shown at (204), the method 200 includes forming a protection cap 110 having a shape that corresponds to a curvature of one or more of the surfaces of the rotor blade 16. More particularly, in an embodiment, the protection cap 110 may be formed via sheet press-forming, laser sheet forming, additive manufacturing, electroforming, cold spraying, rolling, surface hardening, coating deposition, sintering, or similar, as well as combinations thereof.
Further, as mentioned, the protection cap 110 may be formed of a plurality of segments. More particularly, in such embodiments, a first segment 114 of the protection cap 110 may be formed of a tungsten-based metal, whereas a second segment 116 of the protection cap 110 may be formed of a different material. In particular embodiments, the tungsten-based metal may include, for example, pure elemental tungsten, tungsten titanium, tungsten silicon, tungsten nickel, or tungsten aluminum, whereas the different material may include a polymeric material, a shape memory alloy, a nickel alloy (such as nickel chromium or nickel chromium molybdenum, as examples), an aluminum alloy, a titanium alloy, steel, or any other suitable material.
Referring still to
For example, in an embodiment, the protection cap 110 may be secured to one or more of the rotor blades surfaces via at least one of adhesive, mechanical engagement, or any other suitable securement methods. For example, in an embodiment, as mentioned, the mechanical engagement may include a clip-on spring configuration (e.g. exterior to one or more of the rotor blade surfaces) or a clip-in configuration (e.g. interior to one or more of the rotor blade surfaces).
Thus, wherein the mechanical engagement is the clip-on configuration, the method 200 may include forming a thickness of a cross-section of the clip-on spring configuration to vary along at least a portion of the overall length of the protection cap 110, e.g. via additive manufacturing, electroforming, cold spraying, or combinations thereof. Alternatively, the thickness of the cross-section of the clip-on spring configuration may be constant along the overall length of the protection cap 110.
In additional embodiments, as shown generally in
In still further embodiments, as mentioned in reference to
Various aspects and embodiments of the present invention are defined by the following numbered clauses:
Clause 1. A rotor blade assembly, comprising:
at least one rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root, the surfaces constructed of a polymeric composite material; and,
a protection cap arranged adjacent to one or more of the surfaces of the rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade, the protection cap comprising a body defining an overall length, at least a first segment of the protection cap constructed of a tungsten-based metal,
wherein the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.
Clause 2. The rotor blade assembly of clause 1, wherein the protection cap covers at least a portion of the leading edge of the rotor blade.
Clause 3. The rotor blade assembly of any of the preceding claims, wherein the tungsten-based metal comprises at least one of elemental tungsten, tungsten titanium, tungsten silicon, tungsten nickel, or tungsten aluminum.
Clause 4. The rotor blade assembly of any of the preceding claims, wherein the tungsten-based metal is formed into at least one of foil, one or more strips, one or more plates, or one or more sheets.
Clause 5. The rotor blade assembly of any of the preceding claims, wherein the protection cap is secured to the one or more of the surfaces via an adhesive.
Clause 6. The rotor blade assembly of any of the preceding claims, wherein the protection cap comprises a clip-on spring configuration that clips onto the one or more of the surfaces of the rotor blade.
Clause 7. The rotor blade assembly of clause 6, wherein a thickness of a cross-section of the clip-on spring configuration varies along at least a portion of the overall length of the protection cap.
Clause 8. The rotor blade assembly of clause 7, wherein the clip-on spring configuration further comprises at least one of internal thickened edges or external thickened edges.
Clause 9. The rotor blade assembly of any of the preceding claims, wherein the protection cap comprises a clip-in configuration that is secured at least partially within an inner cavity of the rotor blade.
Clause 10. The rotor blade assembly of clause 9, wherein the clip-in configuration comprises a protruding leading edge portion and opposing flanges, the opposing flanges secured to an inner surface of the one or more of the surfaces of the rotor blade within the inner cavity of the rotor blade.
Clause 11. The rotor blade assembly of any of the preceding claims, wherein at least a second segment of the protection cap is constructed of a polymeric material.
Clause 12. The rotor blade assembly of any of the preceding claims, wherein the protection cap is integrated with a lightning protection system of the rotor blade.
Clause 13. A method for manufacturing a rotor blade assembly, the method comprising:
providing at least one rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root, the surfaces constructed of a polymeric composite material;
forming a protection cap having a shape that corresponds to a curvature of one or more of the surfaces of the rotor blade, wherein a first segment of the protection cap is formed of a tungsten-based metal and a second segment of the protection cap is formed of a different material;
arranging the protection cap adjacent to one or more of the surfaces of the rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade; and,
securing the protection cap to the one or more of the surfaces of the rotor blade such that the first segment of the protection cap being formed of the tungsten-based metal is arranged adjacent to the blade tip, the protection cap configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.
Clause 14. The method of clause 13, wherein forming the protection cap further comprises at least one of sheet press-forming, laser sheet forming, additive manufacturing, electroforming, cold spraying, rolling, surface hardening, coating deposition, sintering, or combinations thereof.
Clause 15. The method of clauses 13-14, wherein the tungsten-based metal comprises at least one of elemental tungsten, tungsten titanium, tungsten silicon, tungsten nickel, or tungsten aluminum, the different material comprises at least one of a polymeric material, a shape memory alloy, a nickel alloy, an aluminum alloy, a titanium alloy, or a steel alloy.
Clause 16. The method of clauses 13-15, wherein securing the protection cap to the one or more of the surfaces of the rotor blade further comprises securing the protection cap to the one or more of the surfaces of the rotor blade via at least one of adhesive or mechanical engagement, the mechanical engagement comprising at least one of a clip-on spring configuration, a clip-in configuration, or one or more fasteners.
17. The method of clause 16, further comprising forming a thickness of a cross-section of the clip-on spring configuration to vary along at least a portion of the overall length of the protection cap via at least one of additive manufacturing, electroforming, cold spraying, or combinations thereof.
Clause 18. The method of clause 16, further comprising forming at least one additional feature onto the protection cap via at least one of additive manufacturing, electroforming, cold spraying, or combinations thereof, the at least one additional feature comprising at least one of internal thickened edges, external thickened edges, one or more flanges, or an aerodynamic surface feature.
Clause 19. The method of clause 16, wherein the clip-in configuration comprises a protruding leading edge portion and opposing flanges, the method further comprising:
forming the leading edge portion of a first material and the opposing flanges of a second material, the first and second materials being different;
securing the opposing flanges to an inner surface of the one or more of the surfaces of the rotor blade within the inner cavity of the rotor blade.
Clause 20. A protection cap for arranging adjacent to one or more surfaces of a rotor blade so as to cover at least a portion of the one or more surfaces of the rotor blade, the protection cap comprising:
a body defining an overall length,
wherein at least a first segment of the protection cap is constructed of elemental tungsten, and
wherein the protection cap is configured to reduce erosion and resist corrosion of the rotor blade caused by particle or liquid impact.
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 languages of the claims.
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