Wind turbine blade and method for manufacturing a wind turbine blade with vortex generators

A wind turbine for generating electrical energy may include a wind turbine blade including a plurality of vortex generators integrally formed in the outer surface of the blade. The vortex generator includes a first component that defines a portion of the outer surface of the blade and a second component defining the shape of the vortex generator and at least partially surrounded by the first component. A method of manufacturing the wind turbine blade includes disposing a first plurality of layers of structural material over a mold main body and a removable insert member with a shaped cavity. A shaped plug is then pressed into the shaped cavity, and a second plurality of layers of structural material is disposed over the plug and the mold main body to complete manufacture of a wind turbine blade with a vortex generator.

TECHNICAL FIELD

The invention relates generally to wind turbines, and more particularly, to a wind turbine blade and a method of manufacturing a wind turbine blade including integral vortex generators for modifying the flow of air around the blade.

BACKGROUND

Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A horizontal-axis wind turbine includes a tower, a nacelle located at the apex of the tower, and a rotor having a plurality of blades and supported in the nacelle by means of a shaft. The shaft couples the rotor either directly or indirectly with a generator, which is housed inside the nacelle. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator.

Wind turbines are subject to high aerodynamic loads applied by the wind to the wind turbine blades, including reduced lift forces caused by the separation of air flow around the blade from the blade surface at a boundary layer. As well understood in fluid dynamics, the thickness of a boundary layer tends to increase away from the leading edge of a wind turbine blade. The increased thickness of the boundary layer tends to promote turbulent flow within the boundary layer and reduce the maximum lift coefficient of the wind turbine blade. Consequently, vortex generators are positioned within the boundary layer to create vortices downstream of the vortex generators. The flow vortices force increased mixing of air from the boundary layer and air outside the boundary layer, thereby delaying the boundary layer separation or the rapid increase of thickness in the boundary layer. In this regard, the boundary layer remains closer to the surface of the blade over an increased portion of the wind turbine blade. Therefore, the vortex generators increase the maximum lift coefficient of a wind turbine blade by delaying separation.

Conventional vortex generators for wind turbine blades are generally applied to a blade after the blade has been manufactured because the vortex generators are small features difficult to successfully demold from a 160-foot long (50 meters) or longer blade mold. The vortex generators are typically plate-shaped members composed of a plastic or metal material and adhesively coupled to the outer surface of a wind turbine blade using double-sided tape or similar adhesive materials. The vortex generators must be accurately positioned and then manually adhered on the blade, typically in a piecemeal manner. This individualized process increases the time and cost for producing a wind turbine blade. Furthermore, the affixed vortex generators may be damaged in shipping or from repeated extreme weather conditions.

Thus, there remains a need for an improved molding apparatus and method for manufacturing the wind turbine blades and the vortex generators that address these and other shortcomings in conventional wind turbine manufacturing processes and conventional vortex generators.

SUMMARY

According to one embodiment, a wind turbine blade includes an outer surface and a plurality of vortex generators formed in the outer surface. The vortex generators include a first component defining a portion of the outer surface of the blade and a second component defining the shape of the vortex generator. The second component is at least partially surrounded by the first component. The first component may be composed of a first material, while the second component may be composed of a second material different than the first material.

According to another embodiment, a wind turbine includes a tower, a nacelle located adjacent a top of the tower, and a rotor. The rotor includes a hub and a plurality of blades extending from the hub. At least one of the blades is configured with an outer surface and a plurality of vortex generators as described above.

In another embodiment, a molding apparatus for a wind turbine blade includes a mold main body including a defining surface and at least one recessed cavity. The defining surface is shaped to define the outer surface of the wind turbine blade. The molding apparatus also includes an insert member removably inserted into the at least one recessed cavity. The insert member includes an inner surface defining a vortex generator cavity that opens to the defining surface of the mold main body. The vortex generator cavity is shaped to define a first integral vortex generator on the wind turbine blade. The molding apparatus may include a second insert member having a second vortex generator cavity configured to define a second vortex generator on the wind turbine blade having a different shape.

In an exemplary embodiment, a method of manufacturing a wind turbine blade having at least one vortex generator includes inserting a first removable insert member with a first vortex generator cavity into a recessed cavity of a mold main body. The method further includes disposing a first plurality of layers of structural material over the mold main body and the first removable insert member, and pushing a shaped plug into the first vortex generator cavity to thereby push the first plurality of layers of structural material into the first vortex generator cavity. A second plurality of layers of structural material is then disposed over the mold main body, the first removable insert member, and the shaped plug to form a wind turbine blade with an integral vortex generator. Then the wind turbine blade and the integral vortex generator are demolded from the mold main body and the first removable insert.

The wind turbine blade may be demolded prior to, simultaneous to, or after the demolding of the first removable insert member. In another embodiment, a wind turbine blade including at least one vortex generator is formed by the method of manufacturing a wind turbine blade described above.

DETAILED DESCRIPTION

With reference toFIG. 1, a wind turbine10includes a tower12, a nacelle14disposed at the apex of the tower12, and a rotor16operatively coupled to a generator18housed inside the nacelle14. In addition to the generator18, the nacelle14houses miscellaneous components required for converting wind energy into electrical energy and various components needed to operate, control, and optimize the performance of the wind turbine10. The tower12supports the load presented by the nacelle14, the rotor16, and other components of the wind turbine10that are housed inside the nacelle14and also operates to elevate the nacelle14and rotor16to a height above ground level or sea level, as may be the case, at which faster moving air currents of lower turbulence are typically found.

The rotor16of the wind turbine10, which is represented as a horizontal-axis wind turbine, serves as the prime mover for the electromechanical system. Wind exceeding a minimum level will activate the rotor16and cause rotation in a substantially perpendicular direction to the wind direction. The rotor16of wind turbine10includes a central hub20and a plurality of blades22that project outwardly from the central hub20at locations circumferentially distributed thereabout. In the representative embodiment, the rotor16includes three blades22, but the number may vary. The wind turbine blades22are configured to interact with the passing air flow to produce lift that causes the rotor16to spin generally within a plane defined by the blades22.

The wind turbine10may be included among a collection of similar wind turbines belonging to a wind farm or wind park that serves as a power generating plant connected by transmission lines with a power grid, such as a three-phase alternating current (AC) power grid. The power grid generally consists of a network of power stations, transmission circuits, and substations coupled by a network of transmission lines that transmit the power to loads in the form of end users and other customers of electrical utilities. Under normal circumstances, the electrical power is supplied from the generator18to the power grid as known to a person having ordinary skill in the art.

In order to increase the lift generated by air flowing over the blades22and mitigate blade stall, the blades22are designed and constructed with a plurality of integral vortex generators24typically positioned along a suction side26of the blade22. Although only one spanwise row of integral vortex generators24is illustrated along the suction side26in the figures, the wind turbine blades22may include multiple spanwise rows of integral vortex generators24along the suction side26or on the pressure side28of the blades22in alternative embodiments. As well understood in fluid dynamics, air flowing over the wind turbine blade22forms a boundary layer that may separate from the outer surface of the blade22between a leading edge30of the blade22and a trailing edge32of the blade22, depending on air speed, wing geometry (e.g., angle of attack), or other factors. The integral vortex generators24delay the separation of this boundary layer from the blade outer surface by causing flow vortices to mix air flow above the boundary layer with air flow in the boundary layer. As a result, the integral vortex generators24increase the maximum lift coefficient of a wind turbine blade22with minimal added drag and noise production, which results in increased blade rotation velocity and more power generation.

FIGS. 2-5Bfurther illustrate one embodiment of the wind turbine blade22including integral vortex generators24. Each vortex generator24generally defines a three-dimensional prism-type shape rather than a flat plate, which advantageously provides more robust structure while enabling a molding process to manufacture the wind turbine blade22, as described in further detail below. In the exemplary embodiment illustrated, the three-dimensional shape of the vortex generator24is a triangular prism. However, the specific three-dimensional shape of each vortex generator24may be modified in alternative embodiments of the invention to optimize one or more of the following: increased lift generation, mitigated stall, reduced noise production, and reduced drag.

In the illustrated embodiment, each vortex generator24is formed integrally with the outer surface34of the wind turbine blade22and extends upwardly from the outer surface34. Each vortex generator24includes an upstream surface36, a downstream surface38, and a top edge40at the junction of the upstream surface36and the downstream surface38. The upstream surface36of each vortex generator24is generally perpendicular to the outer surface34of the blade22. Thus, the upstream surface36presents a plate-like flow obstruction facing the leading edge30of the blade22. The upstream surface36produces flow vortices in a similar fashion as conventional plate-like vortex generators. The flow vortices extend downstream from the top edge40and force mixture of flow between a boundary layer close to the outer surface34of the blade22and air flowing above the boundary layer. The downstream surface38of each vortex generator24is angled from the upstream surface36of the vortex generator24and the outer surface34of the blade22to present a smooth contour facing the trailing edge32of the blade22.

As shown most clearly inFIGS. 2-4, the plurality of vortex generators24are arranged in pairs along a length of the blade22. Each pair of vortex generators24are angled from each other such that the pair is arranged in a V-shaped configuration. In this regard, each of the vortex generators24includes an upstream end42directed generally toward the other vortex generator24in the pair of vortex generators and also toward the leading edge30of the blade22. Similarly, each of the vortex generators24includes a downstream end44directed generally away from the other vortex generator24in the pair of vortex generators24and also toward the trailing edge32of the blade22. Each vortex generator24defines a longitudinal length L from the upstream end42to the downstream end44. In an exemplary embodiment, the length L may be about 1% to 5% of the chord length of the blade22measured locally to the vortex generator24. The length L may also be scaled in accordance with the local boundary layer thickness so as to be a set percentage thereof. In the illustrated embodiment, the vortex generators24in each pair of vortex generators24are angled from one another at the respective upstream ends42by approximately 90 degrees, but it will be appreciated that this angle between the vortex generators24may be modified to optimize the performance of the wind turbine10.

A first gap distance G1is defined between the upstream ends42of two vortex generators24in any pair of vortex generators24while a second gap distance G2is defined between the downstream ends44of adjacent pairs of vortex generators24. In the exemplary embodiment, gap distance G1is shorter than gap distance G2, although the respective lengths of gap distances G1and G2may be modified for various applications within the scope of the invention. Additionally, as most readily seen inFIG. 5A, each vortex generator24defines a height H and a width W along a central cross section through the vortex generator24. In one example, the ratio of the height H to the width W is greater than or equal to 1 (i.e., H/W≧1). More specifically, the height H may be about 0.5% to 1% of the chord length of the blade22measured locally to the vortex generator and the width W may be about 0.5% to 1% of the chord length of the blade22measured locally to the vortex generator in one embodiment. The ratio of the height H to the width W may be further modified for various applications of a vortex generator24according to the invention.

The vortex generators24are more clearly illustrated in the cross-sectional views ofFIGS. 5A and 5B. As readily understood from these figures, each vortex generator24is molded into the blade22integrally and includes an outer first component46and an inner second component48. More specifically, the first component46may be the material used to form the contoured outer surface34of the blade22, while the second component48may be a plug member48at least partially surrounded or alternatively completely encased by the first component46. To this end, the plug member generally defines the shape of the vortex generator24, which in the illustrated embodiment, is a triangular prism with tapered upstream and downstream ends42,44. The first component46provides structural robustness and strength by integrally forming the vortex generator24as a continuous part of the outer surface34of the blade22. In the exemplary embodiment, the first component46includes a structural material such as structural fiber weave and a binder, as well understood in the blade manufacturing art, and the plug member48includes injection molded plastic material. More particularly, the structural fiber weave may include fiberglass or another fiber-reinforced plastic material, and the binder may include an epoxy resin, a polyester-based resin, or other resins. Thus, the vortex generator24does not add significant weight to the wind turbine blade22, but the plastic material of the plug member48is protected by the fiberglass weave from degradation and failure caused by ultraviolet radiation. Therefore, the two-component construction of the vortex generator24produces a robust integral member that is not subject to the normal failure modes of conventional vortex generators and is readily manufactured using the method described in further detail below.

According to one conventional process, a wind turbine blade is manufactured by disposing, for example by rolling out, structural outer shell material into two half-molds and then injecting a binder, such as an epoxy resin, polyester resin, or other suitable material around the structural outer shell material while a vacuum bag presses the structural outer shell material into each half-mold. In an alternate process, pre-impregnated composite material may be used which precludes injecting the material with a binder. After curing the binder about the structural outer shell material (e.g., a fiberglass weave) and demolding the outer shell from the mold, the two halves of the wind turbine blade outer shell are coupled to one another around a structural support member or spar. The two halves of the wind turbine blade are typically coupled by adhesive material, thereby completing blade construction. Consequently, the following description will focus on the manufacture of one-half of the wind turbine blade22, and more particularly, the suction side26of the wind turbine blade22between the leading edge30and the trailing edge32. It will be understood that the following method and molding apparatus could be used to form the other half of the wind turbine blade22(i.e., the pressure side28) without departing from the scope of the invention.

FIGS. 6 and 7illustrate an exemplary embodiment of a molding apparatus50used to manufacture the outer shell of the wind turbine blade22with one or more integral vortex generators24. As shown inFIG. 6, the molding apparatus50includes a mold main body52having a defining surface54along an interior side generally corresponding to a negative of the contoured outer surface34of a completed wind turbine blade22. In this regard, the mold main body52bulges outwardly between a first end56corresponding to the leading edge30of the finished blade22and a second end58corresponding to the trailing edge32of the finished blade22. The mold main body52further includes at least one recessed cavity60between the first end56and the second end58and defined by a receptacle62coupled to the mold main body52. The receptacle62may be integrally formed with the mold main body52, or the receptacle62may be removably coupled to the mold main body52by any known fastener. The recessed cavity60breaks the continuity of the defining surface54. The mold main body52and the receptacle62may be composed of fiberglass reinforced with a steel frame (not shown) as well understood in the art.

The molding apparatus50further includes a removable insert member64configured to be inserted into the recessed cavity60of the receptacle62. The insert member64includes an inner surface66configured to be disposed generally coplanar with the defining surface54of the mold main body52. More specifically, the inner surface66of the insert member64and the defining surface54of the mold main body52are configured to collectively form a continuous molding surface for the molding apparatus50. The insert member64is removably coupled to the receptacle62with a fastener68such as a threaded bolt or screw. It will be understood that any type of fastener68may be used to couple the insert member64and the mold main body52in alternative embodiments.

The insert member64shown inFIGS. 6 and 7further includes a shaped vortex generator cavity70adapted to be the negative of the integral vortex generator24previously described. The vortex generator cavity70is configured to open to the defining surface54of the mold main body52. To this end, the vortex generator cavity70defines a three-dimensional shape such as a triangular prism with tapered first and second ends72,74corresponding, respectively, to the upstream end42and the downstream end44of the integral vortex generator24. It will be understood that the vortex generator cavity70may define different shapes for the vortex generator in alternative embodiments of the invention (one of which is described in further detail with reference toFIG. 15Abelow). Thus, the insert member64may be removed and replaced with other inserts having various vortex generator cavity shapes to optimize production of different wind turbine blades22using the same molding apparatus50. Furthermore, the insert member64may be replaced if the insert member64wears out quicker than the corresponding mold main body52.

The insert member64may be composed of various “hard” or “soft” mold materials depending upon the particular application and vortex generator24to be formed. For example, the insert member64may be composed of silicone in some embodiments where the wind turbine blade22and the vortex generators24are to be demolded individually. In this regard, demolding the mold main body52from a 10-ton wind turbine blade22may cause localized stress or bending forces strong enough to deform or break the integral vortex generator24from the blade22. These risks are lessened by the separate demolding of the insert member64from the vortex generator24. A silicone insert member64may also be used where the integral vortex generator24to be formed has intricate contours and features that are difficult to successfully demold. On the other hand, the insert member64may alternatively be composed of a tooling material such as fiberglass, plastic, or aluminum in embodiments where the integral vortex generator24defines less sophisticated (e.g., rounded and shallow) shapes. Regardless of the material used for the insert member64, the demolding of the wind turbine blade22and the vortex generators24may also be conducted simultaneously within the scope of the invention. Other materials may also be used for the insert member64in alternative non-illustrated embodiments.

A first embodiment of a method for manufacturing a wind turbine blade22having an integral vortex generator24as previously described is illustrated inFIGS. 8-11C. The molding apparatus50previously described is first prepared for the manufacturing process. To this end, the removable insert member64with the desired vortex generator cavity70is inserted into the receptacle62at the recessed cavity60of the mold main body52. The insert member64is fastened to the receptacle62with the fastener68. A preliminary coat of binder material may then be applied locally to the vortex generator cavity70. Alternatively, the preliminary coat of binder material may be applied to the entire mold main body52and insert member64, including the vortex generator cavity70. The molding apparatus50is then configured as shown inFIG. 6and is ready for the molding process.

As shown inFIG. 8, a first plurality of layers76(shown as a single layer for simplicity inFIG. 8) of structural material such as a structural fiber weave is disposed or rolled over the mold main body52and the insert member64as indicated by arrow78. As well understood in the wind turbine art, the structural fiber weave may include fiberglass or another fiber-reinforced plastic material applied by rolling continuous sheets of fiberglass material over the defining surface54and the inner surface66of the insert member64. Furthermore, the structural fiber weave may include a composite material pre-impregnated with binder material. The first plurality of layers76of structural fiber weave will define the outer surface34of the finished wind turbine blade22. Also as shown inFIG. 8, the first plurality of layers76of structural fiber weave does not naturally sink completely into the vortex generator cavity70of the insert member64, but the first plurality of layers76of structural fiber weave may sag slightly into the vortex generator cavity70. In embodiments where the binder was pre-applied to the entire mold main body52and the insert member64, the structural fiber weave is effectively pushed into the binder to begin forming a continuous sidewall or outer shell of the wind turbine blade22.

As shown inFIG. 9, the shaped plug member48is then pushed into the vortex generator cavity70as indicated by arrow82. In this regard, the shaped plug member48forces the first plurality of layers76of structural fiber weave fully into the vortex generator cavity70and the binder material sprayed into the vortex generator cavity70. The plug member48is shaped similarly to the vortex generator cavity70such that the plug member48and the first plurality of layers76of structural fiber weave substantially fill the vortex generator cavity70. Thus, the plug member48and the first plurality of layers76of structural fiber weave form a substantially continuous surface facing inwardly from the molding apparatus50. In one exemplary embodiment, a plurality of plug members48are contained in a roll such that a single plug member48may be “rolled” into the vortex generator cavity70by a similar manner as the rolling of the structural fiber weave. It will be appreciated that alternative methods of pushing the plug member48such as manual application may be used in alternative embodiments of the invention.

After the shaped plug member48is pushed into the vortex generator cavity70, a second plurality of layers80of structural material such as structural fiber weave (e.g., fiberglass material) is disposed, such as by being rolled, over the first plurality of layers76of structural fiber weave and the plug member48, as shown inFIG. 10and indicated by arrow84. To this end, the second plurality of layers80of structural fiber weave is effectively rolled over each of the mold main body52, the insert member64, and the plug member48. Another coat of binder may be applied to the first plurality of layers76of structural fiber weave and the plug member48prior to rolling the second plurality of layers80of structural fiber weave in some embodiments, but this coat of binder may not be required. In the previously mentioned alternative embodiment with pre-impregnated composite material, no additional coat of binder may be required. The second plurality of layers80of structural fiber weave will define an interior surface86of the outer shell of the finished wind turbine blade22. Furthermore, the second plurality of layers80of structural fiber weave complete the encasing or surrounding of the plug member48to form the two-component vortex generator24.

After the second plurality of layers80of structural fiber weave is rolled into position, the wind turbine blade22is finished using well-known injection and curing steps. For example, a vacuum bag may be inflated to fill the area beneath the second plurality of layers80of structural fiber weave, and then additional binder material may be injected throughout the first and second pluralities of layers76,80to thoroughly coat and surround the structural fiber weave. The binder and structural fiber weave combination may then be cured by heating to solidify the outer shell of the wind turbine blade22and the first component of the previously-described vortex generator24. Alternatively as discussed above, the structural fiber weave may be pre-impregnated with binder material such that no injection step is required prior to curing the wind turbine blade22. In still other alternative embodiments, the binder may include fillers or may be replaced with other binder materials such as a polyester-based resin within the scope of the invention. In sum, the injection and/or curing steps solidify the wind turbine blade22within the molding apparatus50.

The wind turbine blade22and integral vortex generator24must then be demolded from the main mold body52and the insert member64, respectively.FIGS. 11A-11Cillustrate the plurality of steps involved in this demolding according to the first embodiment of the method. As shown inFIG. 11A, the fastener68is removed from engagement with the receptacle62and the insert member64so that the receptacle62can be removed from the insert member64and the mold main body52in the direction of arrow88. Removing the receptacle62exposes a back side90of the insert member64to provide access for removing the insert member64. The integral vortex generator24is then demolded from the insert member64as shown by arrow92inFIG. 11B. For example, the insert member64may be manually peeled in a gradual manner from the vortex generator24to ensure that the vortex generator24is not damaged in the demolding process. After the vortex generator24is demolded, the blade22is demolded from the mold main body52as shown by arrow94inFIG. 11C. As discussed previously, the separate demolding of the vortex generator24and the blade22protects the vortex generator24from receiving the large forces sometimes applied to the blade22during the demolding process. Even in embodiments with highly sophisticated vortex generator shapes, the first embodiment of the method is configured to reliably demold both the vortex generator24and the blade22because the vortex generator24is subjected to localized manual or mechanical forces when peeling the insert member64. After demolding, the wind turbine blade22with integral vortex generators24is ready for final preparation, curing, and installation as well understood in the art. Furthermore, the wind turbine blade22may include a first plurality of vortex generators formed in a first spanwise row and a second plurality of vortex generators formed in a second spanwise row.

A second embodiment of the method of manufacturing a wind turbine blade22having at least one vortex generator24is illustrated inFIGS. 8-10and12A-12B. Like the first embodiment, the blade22and vortex generator24are formed by disposing or rolling the first plurality of layers76of structural fiber weave over the molding apparatus50, then pushing the plug member48into the vortex generator cavity70of the insert member64, and then disposing or rolling the second plurality of layers80of structural fiber weave over the molding apparatus50. However, the demolding process for the blade22and the integral vortex generators24is modified as shown inFIGS. 12A and 12B.

In this embodiment, the fastener68coupling the insert member64and the receptacle62is removed. Then the wind turbine blade22is demolded from the main mold body52by removing the main mold body52and receptacle62from the blade22in the direction of arrow96inFIG. 12A, leaving the insert member64on the vortex generator24. In this manner, any of the large forces that may be applied during the demolding of the blade22are primarily affecting the insert member64rather than the vortex generator24. As with the previous embodiment, the removal of the receptacle62provides access to the back side90of the insert member64. The vortex generator24is then demolded from the insert member64by manually or mechanically peeling the insert member64from the vortex generator24as shown by arrow98inFIG. 12B. The blade22and the vortex generators24are reliably removed from the molding apparatus50without damaging the vortex generators24using this second embodiment of the method. After demolding, the wind turbine blade22with integral vortex generators24is ready for final preparation, curing, and installation as well understood in the art.

A third embodiment of the method of manufacturing a wind turbine blade22having at least one vortex generator24is illustrated inFIGS. 8-10and13. Again, the blade22and vortex generator24are formed by disposing or rolling the first plurality of layers76of structural fiber weave over the molding apparatus50, then pushing the plug member48into the vortex generator cavity70of the insert member64, and then disposing or rolling the second plurality of layers80of structural fiber weave over the molding apparatus50, as previously described with respect to the first embodiment. In this embodiment, the demolding of the wind turbine blade22and the vortex generator24from the mold main body52and the insert member64is conducted simultaneously. In this regard,FIG. 13illustrates that the fastener68remains coupled to the receptacle62and the insert member64such that the entire molding apparatus50is demolded in one motion indicated by arrow100. This one-step demolding process is advantageous as long as no damage is incurred by the vortex generators24during the demolding process. As such, the third embodiment of the method may be ideal for wind turbine blades22having less sophisticated (i.e., rounded and shallow) vortex generators24. However, the one-step demolding process may be used with any type of vortex generator24formed on the blade22in alternative embodiments.

FIGS. 14A and 14Bsummarize in flowchart form the previously-detailed first and second embodiments of the method for manufacturing a wind turbine blade22having at least one vortex generator24. To this end, the first embodiment of the method102shown inFIG. 14Aincludes inserting the removable insert member64having a shaped vortex generator cavity70into the recessed cavity60of the mold main body52, at step104. A coat of binder may be applied to the vortex generator cavity70at step106. The first plurality of layers76of structural fiber weave is disposed over the mold main body52and the insert member64at step108. The shaped plug member48is pushed or forced into the vortex generator cavity70at step110. The second plurality of layers80of structural fiber weave is disposed over the mold main body52, the insert member64, and the plug member48at step112. The insert member64is then demolded from the wind turbine blade22(and more specifically, the vortex generator24) at step114. Finally, the wind turbine blade22is demolded from the main mold body52at step116. Further explanation of these method steps are provided with reference toFIGS. 8-11C, above.

FIG. 14Billustrates the second embodiment of the method118, which includes each of the same steps104,106,108,110,112,114,116as the previous method. The one difference in the second embodiment of the method118is that the wind turbine blade22is demolded from the main mold body52(step116) before the insert member64is demolded from the wind turbine blade22and the vortex generator24(step114). Thus, further details regarding these method steps are provided with reference toFIGS. 8-10and12A-12B, above.

With any embodiments of the method, the wind turbine blade22is easily formed with integral vortex generators24that reliably demold from a molding apparatus50without damaging the blade22or the vortex generators24. As previously discussed, the number of spanwise rows of vortex generators24and the size and shape of the vortex generators24may be modified without departing from the scope of the invention. In this regard, while only one vortex generator24is shown in cross section in the illustrated embodiments, the demolding process of the blade22simultaneously or individually demolds a series of vortex generators24along with the blade22. Consequently, each of the embodiments of the method are operable to manufacture the wind turbine blade22shown inFIGS. 2-5Bwith robust integral vortex generators24that minimize ultraviolet radiation degradation and other types of vortex generator failure commonly encountered with conventional vortex generators.

As previously discussed, different integral vortex generator24designs may be used in different applications of a wind turbine blade22. To this end, the shape and size of the vortex generator24(including the length L, the height H, the width W, the first gap distance G1, and the second gap distance G2) may be modified to cause optimal changes in noise generation, drag generation, lift coefficient increase, and other aerodynamic factors. The molding apparatus50and associated manufacturing methods of the invention advantageously permit the ready modification of the formed vortex generators24for different applications by modifying the insert member64of the previously described embodiments.

For example,FIG. 15Aillustrates the molding apparatus50including a second removable insert member120. The second removable insert member120includes an inner surface122configured to be disposed generally coplanar with the defining surface54of the mold main body52and a shaped vortex generator cavity124having a rectangular cross section and configured to be open to the defining surface54of the mold main body52. The rectangular vortex generator cavity124is configured to form a vortex generator defining a rectangular prism-shape. Thus, by replacing the first removable insert member64with the second removable insert member120, the molding apparatus50may be modified for molding a wind turbine blade22having vortex generators24of any alternative shape, including but not limited to triangular prisms and rectangular prisms.

Similarly,FIG. 15Billustrates the molding apparatus50including a third removable insert member126. The third removable insert member126includes an inner surface128configured to be disposed generally coplanar with the defining surface54of the mold main body52. More specifically, the third removable insert member126does not include any vortex generator cavity in the inner surface128such that the defining surface54of the mold main body52and the inner surface128of the third removable insert member126approximate a conventional mold without any recessed cavities60or receptacles62. Consequently, by replacing the first removable insert member64with the third removable insert member126, the molding apparatus50may be modified for molding a wind turbine blade22without integral vortex generators24. Therefore, the molding apparatus50and methods of manufacture are easily reconfigured for any wind turbine blade that needs to be manufactured.

The molding apparatus50and methods of manufacture of this invention are operable to form a wind turbine blade22having integral vortex generators24of any size and shape for a particular application. The integral vortex generators24are formed of two components: the structural material that at least partially defines the outer surface34of the wind turbine blade22, and an inner shaped plug member48typically formed of plastic. As such, the resulting vortex generators24are robust and not subject to certain failure modes of conventional vortex generators including but not limited to ultraviolet radiation degradation and tearing off at the outer surface34. Furthermore, the vortex generators24and the wind turbine blade22will reliably come out of the molding apparatus50during a demolding process without causing damage to the vortex generators24. The wind turbine blade22with integral vortex generators24is therefore easily manufactured and advantageous compared to conventional wind turbine blades.

While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the inventor to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, in alternative embodiments, the insert member may be fixedly coupled to the receptacle and not separable therefrom. Thus, the various features of the invention may be used alone or in any combination depending on the needs and preferences of the user.