Rotor blade of a wind turbine and wind turbine

Abstract

A rotor blade of an aerodynamic rotor of a wind turbine, comprising: at least a first and a second wing fence, with the first wing fence being arranged at the rotor blade in radial direction, in relation to an axis of rotation of the rotor, in a range between 25% and 40%, and the second wing fence being arranged at the rotor blade in radial direction, in relation to an axis of rotation of the rotor, in a range between 45% and 60%.

Claims

1. A rotor blade of an aerodynamic rotor of a wind turbine comprising: a first wing fence and a second wing fence, wherein: the first wing fence is arranged at the rotor blade in a radial direction, in relation to an axis of rotation of the rotor, in a range of 25% to 40% along a length of the rotor blade measured from a root of the rotor blade; and the second wing fence is arranged at the rotor blade in the radial direction, in relation to the axis of rotation of the rotor, in a range of 45% to 60% along a length of the rotor blade measured from the root of the rotor blade, wherein the first wing fence has a first mean height and the second wing fence has a second mean height, wherein the first mean height is greater than the second mean height.

2. The rotor blade according to claim 1, wherein: the first wing fence is arranged at the rotor blade in the radial direction, in relation to the axis of rotation of the rotor, in a range of 30% to 35% along the length of the rotor blade measured from the root of the rotor blade; and the second wing fence is arranged at the rotor blade in the radial direction, in relation to the axis of rotation of the rotor, in a range of 50% to 55% along the length of the rotor blade measured from the root of the rotor blade.

3. The rotor blade according to claim 1, wherein: the first and the second wing fences are arranged at a suction side of the rotor blade; or the first and the second wing fences each include fence sections at the suction side and at a pressure side, respectively, of the rotor blade.

4. The rotor blade according to claim 1, wherein each wing fence is designed as a bridge having: a base section, and a rear section, wherein the base section has a shape that corresponds to a surface of the rotor blade, and wherein the rear section has a contour line that corresponds to the surface of the rotor blade.

5. The rotor blade according to claim 1, wherein the first and second mean heights equal a thickness of a boundary layer of air blowing against the rotor blade.

6. The rotor blade according to claim 5, wherein the first and second mean heights are two to five times higher than the boundary layer of air blowing against the rotor blade.

7. The rotor blade according to claim 1, further comprising vortex generators arranged on a suction side of the rotor blade proximate a blade nose of the rotor blade and between the first and second wing fences.

8. The rotor blade according to claim 1, wherein the rotor blade has a profile depth that is greatest at a blade root for attaching to a rotor hub of the aerodynamic rotor.

9. A wind turbine comprising: a plurality of rotor blades according to claim 1.

10. The rotor blade according to claim 1, wherein the first mean height is 5 mm or less and the second mean height is 15 mm or greater.

11. The rotor blade according to claim 1, wherein the first mean height of the first wing fence is at least 30% greater than the second mean height of the second wing fence.

12. The rotor blade according to claim 1, further comprising vortex generators between the first and second wing fences.

13. The rotor blade according to claim 1, further comprising: a blade nose pointing in the direction of movement of the rotor blade; and a rear edge facing away from the blade nose.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 shows a schematic view of a rotor blade.

(2) FIG. 2 shows a diagram, where the relative profile thickness is shown qualitatively above the normalized rotor radius.

(3) FIG. 3 shows a diagram, where the depth is shown qualitatively above the radius.

(4) FIG. 4 shows a diagram, where the thickness is shown qualitatively above the radius.

(5) FIG. 5 shows a perspective view of a wind turbine.

(6) FIG. 6 shows a lateral view of a rotor blade.

(7) FIG. 7 shows another lateral view of the rotor blade of FIG. 6.

(8) FIG. 8 shows a local power coefficient cp loc qualitatively for two conditions, depending on the radial position at the rotor blade.

(9) FIG. 9 shows the first and second wing fences in a rotor blade axial view.

(10) FIG. 10 shows a rotor blade from two perspectives.

(11) FIG. 11 shows a perspective view of one part of the rotor blade.

(12) FIG. 12 shows the exemplary perspective view of some vortex generators.

DETAILED DESCRIPTION

(13) FIG. 1 shows a distribution of various profile geometries of a rotor blade 1 of one embodiment. In rotor blade 1, profile thicknesses 2 and profile depths 3 are shown in sections. On one end, rotor blade 1 features rotor blade root 4, and on the other, far end it features a connection area 5 for mounting a rotor blade tip. The rotor blade has a large profile depth 3 at rotor blade root 4. Profile depth 3 is, however, much smaller in the connection area 5. The profile depth decreases noticeably starting from rotor blade root 4, which may be also referred to as profile root 4, all the way to a central area 6. A cutoff point (which is not shown in this figure) may be provided in the central area 6. The profile depth 3 remains almost steady between the central area 6 and the connection area 5. The depicted rotor blade 1 is intended for mounting a small rotor blade tip that accounts for less than 1% of the length of the depicted rotor blade 1 and therefore can be neglected here.

(14) FIG. 2 shows a diagram, where the relative profile thickness of two different rotor blades of a wind turbine is drawn in above the normalized rotor radius. The relative profile thickness, namely the profile thickness to profile depth ratio, may be stated in %; however, in this case the qualitative course is crucial, and therefore no values have been plotted. Only the values for 38% and 45% are drawn in for orientation purposes. The rotor radius relates to a rotor with at least one rotor blade mounted to a rotor hub of the rotor. The length of the respective rotor blade extends from the rotor blade root to the rotor blade tip. The rotor blade starts with its rotor blade root at a value of about 0.05 of the normalized rotor radius and ends with its rotor blade tip at a value of 1 of the normalized rotor radius. The value of the normalized rotor radius in the area of the rotor blade tip is about equal to the percentage length of the respective rotor blade. The value 1 of the normalized rotor radius is, in particular, equal to 100% of the rotor blade length.

(15) The diagram shows the two graphs 100 and 102. Graph 100 represents the course of the relative profile thickness of a wind turbine for a weak wind site, and graph 102 shows the course of a wind turbine for sites with higher mean wind speeds. From the graphs, it can be seen that the course of the relative profile thickness of graph 102 is monotonically decreasing, in essence. In the area of the rotor blade root, i.e., between a normalized rotor radius of 0.0 and 0.1, graph 102 starts with a relative profile thickness of less than 45%. The values of the relative profile thickness decrease steadily.

(16) Graph 100 of the weak wind installation starts with a clearly higher relative profile thickness. It drops below the drawn-in 45% mark of relative profile thickness only at about 15% of the normalized rotor position and leaves this area only at about 50% of the normalized radius. The difference in relative profile thickness between a weak wind installation pursuant to graph 100 and a strong wind installation pursuant to graph 102 is greatest if the normalized radial position is about 45%.

(17) The illustration thus shows that the decrease in relative thickness in the weak wind installation is much more pronounced on the outskirts than in the strong wind installation. Especially in the range of 40% to 45%, where the relative thickness is the greatest compared to the strong wind installation, it is proposed to provide for boundary fences that can enclose this area and/or to provide for vortex generators.

(18) FIG. 3 shows a diagram that depicts the profile depthreferred to simply as depth in the diagramqualitatively, subject to the rotor radius, whose value normalizes to the maximum radius of the respectively underlying rotor. Graph 200 shows the course for a weak wind installation, which was also underlying the illustration in FIG. 2, whereas graph 202 shows the course of a strong wind installation, which was also underlying FIG. 2. It can be seen therein that the weak wind installation unlike the strong wind installation shows a comparatively low depth at a very early stage, i.e., already at about 50% of the total radius.

(19) FIG. 4 shows a diagram, where the respective profile thicknessreferred to simply as thickness in the diagramis shown for the profile depths of FIG. 3. Here, too, graph 300 for the weak wind installation and graph 402 for the strong wind installation are shown only qualitatively above the normalized radius. Graphs 100, 200 and 300, on the one hand, and graphs 102, 202 and 402, on the other, are based on one and the same wind turbine.

(20) It can be seen that thickness profiles 300 and 302 are very similar for either wind turbine type to ensure the respective structure stability. However, a lesser depth in the outer rotor area is specified for the weak wind installation to make allowance for the special conditions, as shown by graph 200 in FIG. 3 as compared to graph 202. This results in the characteristic course of the relative thickness pursuant to graph 100 with a plateau in the range around about 40%, as shown in FIG. 2.

(21) FIG. 5 shows a wind turbine 400 with a tower 402 built on a base-plate 403. At the upper side opposite the base-plate 403, there is a nacelle 404 (machine house) with a rotor 405 consisting essentially of a rotor hub 406 and rotor blades 407, 408 and 409 that are attached thereto. Rotor 405 is connected to an electrical generator located inside of nacelle 404 for converting mechanical work to electrical energy. Nacelle 404 is rotatably mounted to tower 402, whose base-plate 403 provides the necessary stability.

(22) FIG. 6 shows a lateral view of a rotor blade 500 of an embodiment over its entire length 1, i.e., from 0% to 100%. On one end, rotor blade 500 features a rotor blade root 4, and on the other, far end it features a rotor blade tip 507. In a connection area 505, rotor blade tip 507 is connected to the remainder of the rotor blade. The rotor blade has a large profile depth at rotor blade root 504. The profile depth is, however, much smaller in the connection area 505 and at the rotor blade tip 507. The profile depth decreases noticeably starting from the rotor blade root 504, which may be also referred to as profile root 504, all the way to a central area 506. A cutoff point (which is not shown in this figure) may be provided in the central area 506. The profile depth remains almost steady between the central area 506 and the connection area 505.

(23) Rotor blade 500 has a split shape in the area of rotor blade root 504. Rotor blade 500 thus consists of a basic profile 509, to which yet another section 508 is arranged in the area of the rotor blade root 504 to increase the rotor blade depth of the rotor blade 500. Section 508 is, for example, glued to the basic profile 509. Such split shape is easier to handle during transportation to the installation site and is easier to produce.

(24) What is also shown in FIG. 6 is a hub connection area 510. Rotor blade 500 is connected to the rotor hub through the hub connection area 510.

(25) FIG. 7 shows yet another lateral view of the rotor blade 500 of FIG. 6. What can be seen here is rotor blade 500 with basic profile 509, section 508 to increase the rotor blade depth, central area 506, rotor blade root 504 and hub connection area 510 as well as connection area 505 for rotor blade tip 507. The rotor blade tip 507 is designed as so-called winglet to reduce vortices at the rotor blade tip.

(26) FIGS. 1 to 7 illustrate a rotor blade or a wind turbine, respectively, without showing the wing fences and without showing vortex generators. FIG. 8 shows a problem that may occur with an underlying blade of a weak wind installation. The illustration shows two different courses of the local power coefficient, qualitatively plotted above the relative radius of the rotor blade, namely of the current radius r in relation to the maximum radius R of the underlying rotor. The value 1, i.e., 100%, thus corresponds to the position of the tip of the blade, while the value 0, i.e., 0%, corresponds to the axis of rotation of the underlying rotor. Since the blade does not extend to the zero point, the illustration starts approximately at 0.15. The analysis is based on a tip speed ratio of 9 (=9).

(27) The two curves are simulation results of three-dimensional computational fluid dynamics. They quantitatively show the local power coefficient for two identical but unequally contaminated rotor blades. The upper curve 700 shows the result for a basically ideal rotor blade that does not, in particular, show any contamination. It is marked laminar-turbulent in each case. The lower curve 701 shows the result for basically the same rotor blade that is not in an ideal condition and shows contamination, such as rain or raindrops on the blade. This is referred to as fully turbulent in FIG. 8.

(28) The local power coefficient may drop in case of adverse conditions in a central area of the rotor blade.

(29) FIG. 9 shows a first wing fence 810 and a second wing fence 820. Either one shows a suction side section 811 and 821 and a pressure side section 812 and 822. Each one of these sections 811, 812, 821 and 822 is designed as a bridge and shows a base section B and a rear section R, marked herein with the same letters for the sake of simplicity, to emphasize their functional similarity. Each base section B hence marks, at the same time, the profile of the blade in the respectively depicted section, namely for suction side 801 or for pressure side 802, respectively. All fence sections 811, 812, 821 and 822 continuously increase in height, starting from an area close to rotor blade nose 803 towards rear edge 804. Reference signs 801 to 804 are thus identical for both wing fences 810 and 820, as they relate to the same rotor blade, except that they are shown at different radial positions in the two views of FIG. 9.

(30) FIG. 9 also shows an axis of rotation 806 for either wing fence 810 and 820, about which the pressure side contour or suction side contour, respectively, is pivoted to get the contour of the respective rear section R. This is shown only for the first wing fence 810 and there only for the suction side section 811, but it translates analogously to the pressure side section 812 and also to the wing fence 820, namely, in each case, to the suction side section 821 and the pressure side section 822.

(31) The contour for the rear section R is thus pivoted about pivot angle a, which becomes most noticeable in the end area 808. Pivot angle a may be different for the different wing fence sections 811, 812, 821 and 822. As a result of this design, the fence sections have a height h over the respective blade surface. Height h changes along the respective bridge, i.e., it increases from blade nose 803 to rear edge 804. This means that height h varies along the respective bridge and may also be different for the various fence sections 811, 812, 821 and 822. To illustrate the functional interactions, however, variable h has been selected for every fence section 811, 812, 821 and 822.

(32) FIG. 10 shows two views of a rotor blade 800, namely a top view of the suction side 801 and a top view of the pressure side 802. The rotor blade 800 is shown from the root area 807 to the tip of the blade 808, and the respective top view relates to the area of the blade tip 808. The root area 807 is pivoted in relation to the blade tip area 808, which may be up to 45 to 50, so that the root area 807 does not seem to show the widest area, i.e., the largest profile depth, which is, however, only a phenomenon of the perspective of this pivoted area.

(33) FIG. 10 shows the position of the first wing fence 810 and of the second wing fence 820 and thus the position of the two fence sections 811 and 821 of the suction side and of the fence sections 812 and 822 of the pressure side. The example shown is based on a rotor blade 800 of a rotor with a radius of 46 m. The first wing fence 810 is arranged at a position of 15 m in relation to the radius of the rotor, and the second wing fence 820 is arranged at a position of 25 m.

(34) FIG. 10 moreover shows a suction-side and a pressure-side position line 851 at the suction side 801 or a position line 852 at the pressure side 802, respectively, each of which mark one line along which vortex generators 853 or 854, respectively, are to be arranged. Vortex generators 853 and 854 are likewise merely suggested and may be, in particular, provided for in much greater numbers than shown. In any event, this embodiment shows vortex generators 853 on the suction side 801 only in the area between the first and second wing fences 810 or 820, respectively. This means that vortex generators 854 are also provided for on the pressure side 802, which may be also arranged outside the area between the two wing fences 810 and 820 towards the blade root 807.

(35) The perspective illustration of FIG. 11 basically shows a detail of the rotor blade 800, which essentially shows the suction side 801 of the rotor blade 800. What can be seen here is the position and configuration of the wing fence sections 811 and 821 on the suction side. What can be also seen is the arrangement of the vortex generators 853 between said fence sections 811 and 821. The wing fences or fence sections 821 and 811, respectively, become smaller towards the rotor blade nose 803 and bigger towards the rear edge 804, showing a greater height than towards the rotor blade nose 803.

(36) The wing fences are preferably applied in a blade section plane that is at an angle of 90 to the longitudinal axis of the rotor blade. A deviation therefrom caused by production shall not exceed a tolerance angle of 2 to 5, so that the trailing edge of the wing fencesi.e., the area pointing towards the blade rear edgeis not twisted in the direction of the hub more than said tolerance angle.

(37) FIG. 12 shows a perspective view of some vortex generators 870. One angle of incidence is drawn in schematically in form of an arrow 872. The vortex generators are designed, for example, as triangles with a flat body, which is arranged vertically to the blade surface 874 and at a bias to the angle of incidence 872, and thus at a bias to the rotor blade's direction of movement, with the tilted position alternating from one vortex generator 870 to the next. The vortex generators thus have an alternating tilted position to the wind's angle of incidence. Moreover, the vortex generators resemble, for example, a shark fin in terms of their nature and direction, namely a dorsal shark fin, except that the shark fin is not at a bias to the angle of incidence. The vortex generators 870 may be applied to the rotor blade surface as a vortex generator bar 876.

(38) What is also described hereinafter are preferred embodiments of a rotor blade thatas described above in connection with other embodimentsmay feature two wing fences and, optionally, vortex generators, as described.

(39) Embodiment 1:

(40) A rotor blade (1) of a wind turbine, having: a rotor blade root (4) for connecting the rotor blade (1) to a rotor hub and a rotor blade tip that is arranged at the side facing away from the rotor blade root (4),

(41) wherein a relative profile thickness (2), which is defined as the profile thickness (2) to profile depth (3) ratio, shows a local maximum in a central area (6) between rotor blade root and rotor blade tip.

(42) Embodiment 2:

(43) A rotor blade (1) according to embodiment 1, wherein the relative profile thickness (2) of the local maximum is 35% to 50%, in particular 40% to 45%.

(44) Embodiment 3:

(45) A rotor blade (1) according to one of the embodiments 1 or 2, wherein the rotor blade (1) has a profile depth of 1500 mm to 3500 mm, in particular about 2000 mm, in the area of the local maximum.

(46) Embodiment 4:

(47) A rotor blade (1) according to one of the above embodiments,

(48) wherein the rotor blade (1) is designed for a tip speed ratio in a range between 8 and 11, preferably between 9 and 10.

(49) Embodiment 5:

(50) A rotor blade (1) according to one of the above embodiments,

(51) wherein the rotor blade (1) features in a range of 90% to 95% of the total length of the rotor blade, as measured from the rotor blade root to the rotor blade tip, a profile depth (3) that equals about 5% to 15%, in particular about 10%, of the profile depth (3) in the area of the rotor blade root (4), and/or

(52) that the rotor blade shows a linear thickness profile from 5% to 25% of the total length of the rotor blade, preferably from 5% to 35%, in particular from the rotor blade root to the central area.

(53) Embodiment 6:

(54) A rotor blade (1) according to one of the above embodiments,

(55) wherein the rotor blade (1) has a profile depth (3) of at least 3900 mm at the rotor blade root (4), in particular in a range of 3000 mm to 8000 mm, and/or a profile depth (3) of not more than 1000 mm, in particular in a range of 700 mm to 300 mm, in the range of 90% to 95% of the total length, in particular at 90%, based on the rotor blade root (4).

(56) Embodiment 7:

(57) A rotor blade (1) according to one of the above embodiments,

(58) wherein the rotor blade (1) has a profile depth in the central area that equals about 20% to 30%, in particular about 25%, of the profile depth in the area of the rotor blade root (4).