Abstract
A rotor blade of a wind power installation, comprising an inner section in which the rotor blade is fastened on a rotor hub, and an outer section, which is connected to the rotor blade and comprises a rotor blade tip. The rotor blade has at least partially a flat back profile having a truncated rear edge in the inner section, and at least one control unit for controlling the wake is provided on the rotor blade on the flat back profile.
Claims
1. A wind power installation rotor blade comprising: an inner section having an end configured to fasten the rotor blade to a rotor hub; and an outer section including a rotor blade tip, wherein at least a portion of the inner section includes: a flat back profile having a truncated rear edge, and at least one flow control unit for actively controlling a wake provided on the rotor blade at the flat back profile, wherein the at least one flow control unit comprises at least one cylindrical body having a longitudinal axis, the at least one cylindrical body configured to be rotated about the longitudinal axis, and wherein the at least one flow control unit is provided on the truncated rear edge.
2. The wind power installation rotor blade of claim 1, wherein the at least one cylindrical body is a plurality of cylindrical bodies, each having a longitudinal axis wherein each cylindrical body of the plurality of cylindrical bodies are configured to be rotated about their respective longitudinal axis.
3. The wind power installation rotor blade of claim 2, wherein the plurality of cylindrical bodies are coupled together by a conveyor belt for moving an incident flow flowing around the flat back profile.
4. The wind power installation rotor blade of claim 1, wherein the at least one cylindrical body is configured to be rotated in and counter to an incident flow direction.
5. The wind power installation rotor blade of claim 1, wherein the at least one flow control unit is integrated into the rotor blade.
6. The wind power installation rotor blade of claim 1, wherein the truncated rear edge comprises a recess configured to receive the at least one cylindrical body.
7. The wind power installation rotor blade of claim 1, wherein the at least one flow control unit is provided on one of the upper side or the lower side of the flat back profile.
8. The wind power installation rotor blade of claim 1, wherein a plurality of cylindrical bodies are arranged on the flat back profile in a span width direction of the rotor blade, at least some of the cylindrical bodies having at least one of a different diameter from one another or a different length from one another.
9. The wind power installation rotor blade of claim 9, wherein at least some of the plurality of cylindrical bodies can be rotated with a different rotation speed and rotation direction from one another.
10. A wind power installation rotor blade comprising: an inner section including a root section configured to fasten the rotor blade to a rotor hub, wherein the root region has a cross section that is substantially circular; an outer section including a rotor blade tip; and at least one flow control unit for actively controlling a wake, the at least one flow control unit being provided on the rotor blade at the cross section, wherein the at least one flow control unit comprises a cylindrical body having a longitudinal axis, wherein the cylindrical body is configured to be rotated about the longitudinal axis.
11. A wind power installation comprising: a tower; a nacelle mounted to the tower so that the nacelle is configured rotate relative to the tower; a rotor mounted to the nacelle so that the rotor is configured to rotate relative to the nacelle; and a plurality of rotor blades coupled to the rotor, at least one of the rotor blades being the wind power installation rotor blade of claim 1.
12. A method for controlling a wake of a wind power installation rotor blade comprising: moving an incident flow striking the rotor blade by using at least one flow control unit in such a way that the wake is reduced, the at least one flow control unit being located at a flat back profile of an inner section of the rotor blade.
13. The method as claimed in claim 12, comprising rotating the at least one flow control unit with a predetermined circumferential speed.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0024] The invention will be explained by way of example below with the aid of exemplary embodiments with reference to the appended figures. The figures sometimes contain simplified schematic representations.
[0025] FIG. 1 shows a wind power installation in a perspective view,
[0026] FIG. 2 shows a cross section of a rotor blade according to the prior art,
[0027] FIG. 3 shows a detail of a rotor blade according to the invention,
[0028] FIG. 4 shows the cross section of the flat back profile,
[0029] FIG. 5 shows an exemplary embodiment of a flat back profile according to the invention with a flow control unit,
[0030] FIG. 6 shows another exemplary embodiment of a flat back profile according to the invention,
[0031] FIG. 7 shows another exemplary embodiment of a flat back profile according to the invention,
[0032] FIG. 8 shows another exemplary embodiment of a flat back profile according to the invention,
[0033] FIG. 9 shows another exemplary embodiment of a rotor blade according to the invention,
[0034] FIG. 10 shows a cross section of the rotor blade of FIG. 9, and
[0035] FIG. 11 shows a cross section of a rotor blade according to one aspect of the invention.
DETAILED DESCRIPTION
[0036] FIG. 1 shows a wind power installation 100 with a tower 102 and a nacelle 104. A rotor 106 having three rotor blades 108 and a spinner 110 is arranged on the nacelle 104. The rotor 106 is set in a rotational movement by the wind during operation, and thereby drives a generator in the nacelle 104.
[0037] FIG. 2 shows a cross section of a profile 1 of a rotor blade of a wind power installation according to the prior art. Such a cross section comprises a front edge 2 and a rear edge 3. At the rear edge 3, the lower side 4 and the upper side 5 meet one another. The rear edge 3 converges acutely and shallowly. The rear edge thickness 8 i.e. the thickness of the profile 1 at the rear edge 3 is almost zero. The maximum profile thickness 7 of the profile 1 is arranged in the direction of the front edge 2. Furthermore, the profile chord 6, which extends from the front edge 2 to the rear edge 3, is represented in FIG. 2.
[0038] FIG. 3 shows a detail of a rotor blade 20. The rotor blade 20 is divided into an inner section 25 and an outer section 24. The outer section 24 comprises a rotor blade tip 21. The connection to the rotor blade hub in the inner section 25 is not represented in this case. Various cross sections or profiles 26, 27 are represented in the rotor blade 20 in FIG. 3. Three flat back profiles 26 and one conventional profile 27 are represented in the inner section 25. Two conventional profiles 27 can be seen in the outer section 24. The flat back profiles 26 have a profile thickness 28 at the rear edge 23 which is greater than zero, and in particular lies in the range of from 0.5 to 5 m. The conventional profiles 27 taper shallowly and acutely at the rear edge 23, and correspondingly have a thickness 28 of almost zero at the rear edge 23. In the rotor blade 20, a (flow) control unit for controlling the wake is in this case provided in the form of a cylindrical roller 33 at the rear edge 23. Such a rotor blade complies in particular with the maximum transport dimensions specified for transport. Furthermore, it can generate at least the same power as a rotor blade with a conventional profile, as shown by way of example in FIG. 2.
[0039] As an alternative, a plurality of (flow) control units may be provided on such a flat back profile. The plurality of control units in this case vary particularly in respect of the diameter, their length and/or rotational speed.
[0040] FIG. 4 shows the cross section of a flat back profile 26 without a (flow) control unit. The flat back profile 26 has a truncated rear edge 23 with a large rear edge thickness 28. An incident flow 29 of the wind strikes the flat back profile 26. At the front edge 22, the incident flow 29 is divided and flows around the flat back profile 26 on the lower side 30 and the upper side 31. The incident flow in this case bears on the upper side 31 and the lower side 30. Behind the rear edge 23 in the direction of the profile depth, the incident flow 29 is she. Vortices 32 are formed, which create a wake at the rotor blade. Because of this, the lift coefficient of the flat back profile 26 is reduced and the resistance coefficient is increased. The performance of the wind power installation overall is reduced.
[0041] FIG. 5 shows a cross section of a rotor blade. The cross section is in this case configured as a flat back profile 46. The flat back profile 46 comprises a front edge 42 and a rear edge 43, as well as an upper side 51 and a lower side 50. The rear edge 43 has a large rear edge thickness 48. An incident flow 49 flows around the flat back profile 46. The incident flow 49 is divided at the front edge 42, in order again to flow on the upper side 51 and the lower side 50. At the rear edge 43, a first roller 53 and a second roller 54 are provided as an exemplary embodiment of a (flow) control unit. The first roller 53 is arranged on the upper side 51, and the second roller 54 is arranged on the lower side 50. The first roller 53 has a first longitudinal axis 55, and the second roller 54 has a second longitudinal axis 56. The first roller 53 can be rotated about the first longitudinal axis 55, and the second roller 54 can be rotated about the second longitudinal axis 56. The rotation directions are represented by an arrow 57 and 58, respectively. The first roller 53 and the second roller 54 accordingly each rotate in the direction of the flow of the flat back profile 46 being flowed around. The rotation direction of the first and second rollers 53, 54 may, however, also take place in the clockwise direction, i.e., one roller rotates in the direction of the flow and one counter to the flow. In this way, the incident flow 49 is taken up by the first roller 53 or the second roller 54, respectively, and is therefore moved or accelerated. The wake is reduced. Fewer and smaller vortices 52 are formed in the region of the rear edge 43. The lift coefficient of the rotor blade is thereby increased and the resistance coefficient is reduced. An increase in the output of the wind power installation is therefore achieved.
[0042] FIG. 6 shows another exemplary embodiment of a cross section of a flat back profile 66 of a rotor blade of a wind power installation. An incident flow 69 flows around the flat back profile 66. The flat back profile 66 comprises an upper side 71 and a lower side 70, as well as a truncated rear edge 63 and a front edge 62. In contrast to FIG. 5, a first conveyor belt 81 and a second conveyor belt 79 are provided at the rear edge 63 as an exemplary embodiment of a (flow) control unit. The first conveyor belt 81 and the second conveyor belt 79 enclose a first roller pair 73 and a second roller pair 74, respectively, each comprising two rollers arranged in the profile depth direction. The first conveyor belt 81 and the second conveyor belt 79 connect to one another the two rollers of the first roller pair 73 and the two rollers of the second roller pair 74, respectively. The first conveyor belt 81 is arranged on the upper side 81, and the second conveyor belt 79 is arranged on the lower side of the rear edge 63 of the flat back profile 66. The incident flow 69 is moved by the first conveyor belt 71 and the second conveyor belt 79, respectively. The wake is thereby reduced.
[0043] FIG. 7 shows another embodiment of a cross section of a rotor blade of a wind power installation. The cross section is configured as a flat back profile 460. The flat back profile 460 comprises a front edge 420 and a rear edge 430, as well as an upper side 510 and a lower side 500. An incident flow 490 flows around the flat back profile 460. The incident flow 490 is divided at the front edge 420 in order to flow around the upper side 510 and the lower side 500. In contrast to the flat back profile represented in FIG. 5, a first roller 530 and a second roller 540 are integrated into the rotor blade as an exemplary embodiment of a (flow) control unit, i.e., the first roller 530 and the second roller 540 are not provided as a termination on the rear edge 430. The first roller 530 and the second roller 540 are arranged behind the rear edge 430, first cladding 511 and second cladding 501 respectively also being provided behind the first roller 530 and the second roller 540. The first roller 530 and the second roller 540 are therefore at least partially contained in the flat back profile 460. The first roller 530 and the second roller 540 move the incident flow 490 but are nevertheless for the most part protected from environmental influences. The first roller 530 and the second roller 540 therefore have a long lifetime. The wake is also reduced in its extent in this exemplary embodiment. This exemplary embodiment therefore also has the advantages mentioned above.
[0044] FIG. 8 shows another embodiment of a cross section of a rotor blade of a wind power installation. An incident flow 690 flows around the flat back profile 660. The flat back profile 660 comprises an upper side 710 and a lower side 700, as well as a truncated rear edge 630 and a front edge 620. A first conveyor belt 712 and a second conveyor belt 790 are provided on the rear edge 630. The first conveyor belt 712 and the second conveyor belt 790 enclose a first roller pair 730 and a second roller pair 740, each comprising two rollers arranged in the profile depth direction. The first conveyor belt 712 and the second conveyor belt 790 are respectively integrated into the rotor blade. First cladding 711 and second cladding 701 are respectively provided behind the first conveyor belt 712 and the second conveyor belt 790. The first roller 730 and the second roller 740 are therefore at least partially contained in the flat back profile 660.
[0045] FIG. 9 shows another exemplary embodiment of a rotor blade 200. The rotor blade 200 comprises a front edge 220 and a rear edge 230, as well as an inner section 250 and an outer section 240. The root region 251 of the rotor blade 200, i.e., the region in which the rotor blade 200 is connected to the rotor blade hub, is provided in the inner section 250. The root region 251 has a round cross section 252. The outer section 240 extends approximately from half-way along the rotor blade 200 to the rotor blade tip 210. Two first rollers 253 are provided as an exemplary embodiment of two control units on the round cross section 252. The two first rollers 253 are in this case configured cylindrically.
[0046] FIG. 10 shows the round cross section 252 of the rotor blade 200 of FIG. 9. An incident flow 290 of the wind flows around the round cross section 252. A first roller 253 and a second roller 254 are arranged on one side of the round cross section 252. The first roller 253 has a first longitudinal axis 255, and the second roller 254 has a second longitudinal axis 256. The first roller 253 and the second roller 254 rotate in the direction of the arrow 257 or 258, respectively, i.e., in the direction of the incident flow 290. As a result, the wake is decreased, vortex generation is reduced and, consequently, the lift coefficient is increased and the resistance coefficient is reduced. The output of the wind power installation is therefore increased. As an alternative thereto, the first and second rollers 253, 254 may respectively rotate in the clockwise direction, i.e., the first roller 253 rotates with the flow and the second roller 254 rotates counter to the flow.
[0047] FIG. 10 furthermore shows two guide plates 259, which connect the round cross section 252 to the first roller 253 and the second roller 254, respectively. Because of the guide plates 259, the flow is deviated in the direction of the first roller 253 and the second roller 254, respectively. The flow is thereby deviated from the outer sides of the round cross section toward the middle. The flow is controlled, and the wake is correspondingly also controlled.
[0048] FIG. 11 shows a schematic cross section of a wind power installation rotor blade according to another exemplary embodiment. The cross section is configured here as a flat back profile 46. The flat back profile comprises a front edge 42 and a rear edge 43, as well as an upper side 51 and a lower side 50. The rear edge 43 comprises a first and a second recess 43a, 43b. A first roller 53 is provided in the region of the first recess 43a, and a second roller 54 is provided in the region of the second recess 43b. The first roller 43 has a first longitudinal axis 55, and the second roller 54 has a second longitudinal axis 56. The first roller 53 is rotatable around the first longitudinal axis 55 and the second roller 54 is rotatable around the second longitudinal axis 56. The rotation directions are respectively represented by an arrow 57, 58. According to this aspect, the rotation directions of the first and second rollers are the same. This therefore means that the first roller rotates in the flow direction, while the second roller 54 rotates counter to the flow direction. According to this aspect, the first and second rollers 53, 56 are provided in the first and second recesses 43a, 43b in such a way that the first and second rollers are provided within an imaginary extended contour of the upper and lower sides 51, 50.
[0049] The first and second rollers are therefore embedded in the profile contour of the rotor blade by the rollers being provided in the region of the first and second recesses.
[0050] Flow control is provided by the provision of the first and second rollers and of the corresponding rotation directions.
[0051] According to one aspect, the first and second rollers 53, 54, 253, 254 are arranged in the region of the flat back profile in such a way that they do not protrude beyond the extended rear edge profile contour. In other words, if the rotor blade were not provided with a flat back profile, then the rollers would have to lie within the contour of the imaginary rear edge. The two rollers therefore lie within an imaginary contour of the rear edge when this rear edge is extended with the present gradient.
[0052] By virtue of such an arrangement, it is possible to provide a rotor blade having a high lift coefficient.
