The present subject matter relates generally to wind turbine rotor blades and, more particularly, to a spar configuration between segments of a jointed blade.
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 from wind using known foil principles and transmit the kinetic energy through rotational energy 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.
Wind turbine rotor blades generally include a body shell formed by two shell halves of a composite laminate material. The shell halves are generally manufactured using molding processes and then coupled together along the corresponding ends of the rotor blade. In general, the body shell is relatively lightweight and has structural properties (e.g., stiffness, buckling resistance, and strength) which are not configured to withstand the bending moments and other loads exerted on the rotor blade during operation.
In recent years, wind turbines for wind power generation have increased in size to achieve improvement in power generation efficiency and to increase the amount of power generation. Along with the increase in size of wind turbines for wind power generation, wind turbine rotor blades have also significantly increased in size (e.g., up to 55 meters in length), resulting in difficulties in integral manufacture as well as conveyance and transport of the blades to a site.
In this regard, the industry is developing sectional wind turbine rotor blades wherein separate blade segments are manufactured and transported to a site for assembly into a complete blade (a “jointed” blade). In certain constructions, the blade segments are joined together by a beam structure that extends span-wise from one blade segment into a receiving section of the other blade segment. Reference is made, for example, to US Patent Publication No. 2015/0369211, which describes a first blade segment with a beam structure extending lengthways that structurally connects with a second blade segment at a receiving section. The beam structure forms a portion of the internal support structure for the blade and includes a shear web connected with a suction side spar cap and a pressure side spar cap. Multiple bolt joints are on the beam structure for connecting with the receiving end of the second blade segment, as well as multiple bolt joints located at the chord-wise joint between the blade segments.
Similarly, US Patent Publication No. 2011/0091326 describes a jointed blade wherein a first blade portion and a second blade portion extend in opposite directions from a joint. Each blade portion includes a spar section forming a structural member of the blade and running lengthways, wherein the first blade portion and the second blade portion are structurally connected by a spar bridge that joins the spar sections. The spar bridge may be an extension of one of the spar sections that is received in a receiving spar section of the other blade portion. As the extending spar section may be received in the receiving spar section, the extending spar caps and the receiving spar caps may overlap each other along at least a part of the length of the extending spar section. To limit the material thickness of the overlapping spar caps, the references describes that the thickness of the receiving spar caps may be tapered down towards the joint, i.e. along at least a part of the length of the receiving spar section.
It has been found that a critical structural consideration in such jointed blades is how to keep the joint elements/receiving structures strongly connected or bonded the blade shell, particularly at the exposed area of joint line between the blade segments. The stress at this location is driven by the stiffness of the web reinforcements in conjunction with the stiffness of the shell. In addition, the conductive carbon materials used in the joint elements at the exposed joint lines are more susceptible to lightning strikes.
Therefore, an improved joint structure between the blade segments of a jointed blade that addresses the issues noted would be an advantageous advancement in the art.
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 jointed wind turbine rotor blade that includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the blade segments has a pressure side shell member and a suction side shell member. An internal spar structure runs span-wise through the blade segments and includes a beam structure that extends span-wise from the first blade segment. This beam structure may be an integral extension of the spar structure within the first blade segment, or may be a separate structure that is fixed to the spar structure in the first blade segment. A receiving section is formed in the second blade segment for receipt of the beam structure and includes opposite spar caps and opposite interconnecting webs. In one embodiment, this receiving section is formed as a box-beam structure within the second blade segment into which the beam structure slides, and which may be a section of the internal spar structure formed within the second blade segment.
In a particular embodiment, the spar caps in the receiving section have a constant thickness along the receiving section where the spar caps overlap with the beam structure to produce a desired stiffness of the spar caps along the receiving section. The spar caps are formed from a material or combination of materials along the receiving section that may further contribute to the desired stiffness characteristic.
In a certain embodiment, the receiving section spar caps may be formed from a single material along the receiving section, which may be a high-strength conductive material such as a carbon fiber material, or a non-conductive material, such as a glass fiber material.
In an alternate embodiment, the receiving section spar caps may be formed from a combination of materials along the receiving section, including a non-conductive material at a terminal end thereof at the chord-wise joint. For example, the entirety of the constant thickness of the spar caps at the chord-wise joint may be defined by the non-conductive material, wherein such non-conductive material extends span-wise away from the chord-wise joint for a defined length. A transition may be defined between the non-conductive material and a different material, such as a higher-strength conductive material (e.g., a carbon material) along the receiving section that maintains the constant thickness along the receiving section. For example, the transition may include tapering overlapping sections of a carbon conductive material and the non-conductive material.
In addition to the spar caps having the constant thickness, the webs (e.g., shear webs) along the receiving section may be formed entirely of a high strength conductive material, such as a carbon fiber material, but include a reduced amount of such material at the chord-wise joint line as compared to a defined distance from the chord-wise joint line. This configuration serves to decrease the amount of conductive material exposed to potential lightning strikes at the joint line. For example, in one embodiment, the webs may include a cutout region adjacent the chord-wise joint line. This cutout region may be, for example, a curved, semi-circular, or straight-sided (e.g., triangular) region that removes at least a portion of the conductive material from the webs adjacent to the joint line.
In an alternate embodiment that reduces the amount of conductive material at the joint line, the interconnecting webs may have a tapering thickness of the carbon material approaching the chord-wise joint line. The interconnecting webs may also taper towards the chord-wise joint line regardless of their material make-up.
In still another embodiment, the interconnecting webs may include a transition from the carbon material to a non-conductive material at a distance from the chord-wise joint line such that the non-conductive material is at the joint line.
In other aspects, the present disclosure is drawn to a jointed wind turbine rotor blade that includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the blade segments has a pressure side shell member and a suction side shell member. An internal spar structure runs span-wise through the blade segments and includes a beam structure that extends span-wise from the first blade segment. This beam structure may be an integral extension of the spar structure within the first blade segment, or may be a separate structure that is fixed to the spar structure in the first blade segment. A receiving section is formed in the second blade segment for receipt of the beam structure and includes opposite spar caps and opposite interconnecting webs. In one embodiment, this receiving section is formed as a box-beam structure within the second blade segment into which the beam structure slides, and which may be a section of the internal spar structure formed within the second blade segment. The spar caps in the receiving section are formed of a non-conductive material at a terminal end thereof at the chord-wise joint, wherein the non-conductive material reduces the risk of a lightning strike to the spar caps at the joint line. In this embodiment, the entirety of the spar caps at the chord-wise joint may be defined by the non-conductive material, wherein the non-conductive material extends span-wise away from the chord-wise joint for a defined length. A transition may be defined between the non-conductive and a higher-strength conductive material (e.g., a carbon fiber material) along the receiving section. This transition may taper overlapping sections of the conductive material and the non-conductive material.
In yet another aspect, the present disclosure is drawn to a jointed wind turbine rotor blade that includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the blade segments has a pressure side shell member and a suction side shell member. An internal spar structure runs span-wise through the blade segments and includes a beam structure that extends span-wise from the first blade segment. This beam structure may be an integral extension of the spar structure within the first blade segment, or may be a separate structure that is fixed to the spar structure in the first blade segment. A receiving section is formed in the second blade segment for receipt of the beam structure and includes opposite spar caps and opposite interconnecting webs. In one embodiment, this receiving section is formed as a box-beam structure within the second blade segment into which the beam structure slides, and which may be a section of the internal spar structure formed within the second blade segment. The interconnecting webs are formed at least in part from a high-strength conductive material (e.g., a carbon fiber material) but have a reduced amount of such conductive material at the chord-wise joint line as compared to a defined distance from the chord-wise joint line. For example, the interconnecting webs may include a cutout region adjacent the chord-wise joint line, or a tapering thickness of the conductive material approaching the chord-wise joint line.
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.
Generally, the present subject matter is directed to jointed wind turbine rotor blades having an improved joint configuration that serves to keep the joint elements/receiving structures strongly connected or bonded the blade shell, particularly at the exposed area of joint line between the blade segments where the stresses are generally dictated by the stiffness of the web reinforcements in conjunction with the stiffness of the shell. In addition, in certain embodiments, the joint configuration reduces the use of conductive carbon materials at the exposed joint lines to minimize lightning strikes to the blade at the joint.
Referring now to the drawings,
The first blade segment 30 may include one or more first bolt joints towards a first end 54 of the beam structure 40. For example, a bolt tube 52 may be located on the end 54 of the beam structure 40 and oriented in a span-wise direction. The first blade segment 30 may also include a bolt joint slot 50 located on the beam structure 40 proximate to the chord-wise joint 34 and oriented in a chord-wise direction. There may be a bushing within the bolt joint slot 50 arranged in a tight interference fit with a bolt tube or pin used to connect the second blade segment 32 to first blade segment 30. It should be appreciated that any combination of bolt tubes 52 and bolt slots 50 may be configured between the beam structure 40 and a receiving section 60 (
In the embodiment depicted in
In addition, the embodiments of the receiving section 60 described above having spar caps 68, 70 with the constant thickness 74 may include a configuration of the interconnecting webs 72 that minimize the amount of conductive material presented at the joint line 34. For strength considerations, the webs 72 are typically formed from a high-strength carbon fiber material (which is conductive). The unique webs 44 of the present disclosure may be configured with a reduced amount of the carbon material at the chord-wise joint 34 as compared to the amount of carbon material in the webs 44 at a defined distance from the chord-wise joint 34. For example, the interconnecting webs comprise a cutout region 88 adjacent the chord-wise joint line. In
In an alternate embodiment that reduces the amount of conductive material in the webs 72 adjacent to the joint 34 depicted in
Referring to
The present invention also encompasses embodiments of a wind turbine rotor blade 28 wherein the spar caps 68, 70 in the receiving section 60 are formed with a non-conductive material 78 at the terminal end 80 thereof at the chord-wise joint 34 (referring, for example, to
Referring to
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.
Number | Name | Date | Kind |
---|---|---|---|
851196 | Bevans et al. | Apr 1907 | A |
4474536 | Gougeon et al. | Oct 1984 | A |
4643646 | Hahn et al. | Feb 1987 | A |
4732542 | Hahn et al. | Mar 1988 | A |
5281454 | Hanson | Jan 1994 | A |
7334989 | Arelt | Feb 2008 | B2 |
7344360 | Wetzel | Mar 2008 | B2 |
7521105 | Bech et al. | Apr 2009 | B2 |
7901188 | Llorente Gonzalez et al. | Mar 2011 | B2 |
7922454 | Riddell | Apr 2011 | B1 |
7927077 | Olson | Apr 2011 | B2 |
7997874 | van der Bos | Aug 2011 | B2 |
7998303 | Baehmann et al. | Aug 2011 | B2 |
8123488 | Finnigan et al. | Feb 2012 | B2 |
8297932 | Arocena De La Rua et al. | Oct 2012 | B2 |
8348622 | Bech | Jan 2013 | B2 |
8356982 | Petri Larrea et al. | Jan 2013 | B2 |
8376713 | Kawasetsu et al. | Feb 2013 | B2 |
8388316 | Arocena De La Rua et al. | Mar 2013 | B2 |
8517689 | Kyriakides et al. | Aug 2013 | B2 |
8562296 | Arocena De La Rua | Oct 2013 | B2 |
8721829 | Jacobsen | May 2014 | B2 |
8777578 | Hancock | Jul 2014 | B2 |
8777579 | Hancock | Jul 2014 | B2 |
8828172 | Overgaard | Sep 2014 | B2 |
8899936 | Hancock | Dec 2014 | B2 |
10563636 | Yarbrough | Feb 2020 | B2 |
20050180854 | Gmbau et al. | Aug 2005 | A1 |
20070018049 | Stuhr | Jan 2007 | A1 |
20090116962 | Pedersen et al. | May 2009 | A1 |
20090155084 | Livingston et al. | Jun 2009 | A1 |
20090162208 | Zirin et al. | Jun 2009 | A1 |
20100215494 | Bech et al. | Aug 2010 | A1 |
20100272570 | Arocena De La Rua | Oct 2010 | A1 |
20100304170 | Frederiksen | Dec 2010 | A1 |
20110052403 | Kawasetsu | Mar 2011 | A1 |
20110081247 | Hibbard | Apr 2011 | A1 |
20110081248 | Hibbard | Apr 2011 | A1 |
20110091326 | Hancock | Apr 2011 | A1 |
20110158788 | Bech et al. | Jun 2011 | A1 |
20110158806 | Arms et al. | Jun 2011 | A1 |
20110171032 | Hancock | Jul 2011 | A1 |
20110189025 | Hancock | Aug 2011 | A1 |
20110229336 | Richter et al. | Sep 2011 | A1 |
20110262283 | Hancock | Oct 2011 | A1 |
20120093627 | Christenson et al. | Apr 2012 | A1 |
20120196079 | Brauers et al. | Aug 2012 | A1 |
20120213642 | Wang et al. | Aug 2012 | A1 |
20120269643 | Hibbard et al. | Oct 2012 | A1 |
20120308396 | Hibbard | Dec 2012 | A1 |
20130040151 | Jeromerajan et al. | Feb 2013 | A1 |
20130064663 | Loth et al. | Mar 2013 | A1 |
20130068389 | Overgaard | Mar 2013 | A1 |
20130129518 | Hayden et al. | May 2013 | A1 |
20130164133 | Grove-Nielsen | Jun 2013 | A1 |
20130177433 | Fritz et al. | Jul 2013 | A1 |
20130189112 | Hedges et al. | Jul 2013 | A1 |
20130189114 | Jenzewski et al. | Jul 2013 | A1 |
20130219718 | Busbey et al. | Aug 2013 | A1 |
20130224032 | Busbey | Aug 2013 | A1 |
20130236307 | Stege | Sep 2013 | A1 |
20130236321 | Olthoff | Sep 2013 | A1 |
20140286780 | Lemos et al. | Sep 2014 | A1 |
20150204200 | Eyb et al. | Jul 2015 | A1 |
20150369211 | Merzhaeuser | Dec 2015 | A1 |
20180051672 | Merzhaeuser | Feb 2018 | A1 |
20190032632 | Danielsen | Jan 2019 | A1 |
20200147912 | Thomsen | May 2020 | A1 |
Number | Date | Country |
---|---|---|
2186622 | May 2010 | EP |
3144526 | Mar 2017 | EP |
2710871 | Apr 1995 | FR |
2477847 | Aug 2011 | GB |
WO2009034291 | Mar 2009 | WO |
WO2009077192 | Jun 2009 | WO |
WO2011064553 | Jun 2011 | WO |
WO2011066279 | Jun 2011 | WO |
WO2015051803 | Apr 2015 | WO |
WO2015185066 | Dec 2015 | WO |
Entry |
---|
International Search Report, dated Nov. 20, 2019. |
Number | Date | Country | |
---|---|---|---|
20200072189 A1 | Mar 2020 | US |