Rotor blade for a wind turbine and wind turbine

Abstract

The present invention relates to a rotor blade (10) for a wind turbine, the rotor blade (10) having a rotor blade root (12) defining a reference plane (BE) for attachment to a hub. A profile region (16) is adjacent to the rotor blade root (12) and extends to the rotor blade tip (26). In the profile region (16), the rotor blade (10) has a blade profile (28) defining a chord length (34). The chord angle (α) between the reference plane (BE) and the chord length (34) increases over the entire profile region (16) from the rotor blade root (12) toward the rotor blade tip (26).

Description

Technical Field

[0001] The present invention relates to a rotor blade for a wind turbine and a wind turbine. Background Technology

[0002] Rotor blades of wind turbines and wind turbines having rotor blades are well known and disclosed, for example, in documents EP 3330 530 A1, EP 3 147 499 A1, EP 2 840 255 A2, EP 1 019 631 B1, WO 2019 / 030205 A1, WO 2018 / 046067 A1, WO 2010 / 046000 A2 and NL 1030111. Summary of the Invention

[0003] In particular, the present invention relates to rotor blades of wind turbines and wind turbines having such rotor blades, the wind turbine having a rotor diameter of 1.5m to 8m or a rotor blade length of about 0.75m to about 4m.

[0004] The purpose of this invention is to provide a rotor blade for a wind turbine and a wind turbine having such a rotor blade, which have good start-up performance with low noise emissions.

[0005] In a known manner, wind turbine rotor blades have rotor blade roots for securing the rotor blades to the turbine shaft or to the hub. The rotor blade roots define a reference plane. The hub is typically attached to the turbine shaft. During operation, the turbine shaft or its axis of rotation is at least substantially aligned with the direction of the incoming wind.

[0006] The profile region of the rotor blade is adjacent to the root of the rotor blade and extends to the tip region of the rotor blade away from the root. Preferably, the profile region extends to the tip of the rotor blade, that is, to the free end of the rotor blade; however, it is also conceivable that in the tip region of the rotor blade, the profile region terminates at a certain distance from the tip of the rotor blade, and the rotor blade has rotor blade elements of different shapes along the profile region to the tip of the rotor blade.

[0007] The leading and trailing edges of the rotor blades extend along the entire length of the profile region. The blade profile of the rotor blade extends from the leading edge to the trailing edge over the entire profile region, and the blade profile has an upper side forming the suction side and a lower side forming the pressure side.

[0008] The upper side is on the leeward side, while the lower side is on the windward side.

[0009] The chord length of the blade profile extends through the leading and trailing edges of the rotor blade. The chord length and the reference plane enclose a chord angle, with the lower side of the blade profile facing the reference plane and the upper side of the blade profile moving away from the reference plane.

[0010] The distance between the reference plane and the chord length increases in the direction toward the leading edge of the rotor blade.

[0011] When the rotor blades 10 are assembled, the reference plane BE surrounds the wind turbine shaft 18 and its rotation axis 20 with an angle of attack β, which is preferably a maximum of 70° and a minimum of 50°. This angle of attack β is the smallest measurable angle between the rotation axis 20 and the reference plane BE.

[0012] The underside of the blade profile is designed to be propelled by the wind.

[0013] According to the present invention, the chord angle increases in the profile region from the root of the rotor blade toward the tip region of the rotor blade.

[0014] Experiments and computer simulations show that this type of rotor blade and wind turbine with this type of rotor blade have demonstrated good CP values ​​at low wind speeds, such as 4.5 to 5 meters per second, and have low noise emissions, thus exhibiting good start-up performance.

[0015] In a preferred manner, the chord angle increases continuously, particularly preferably at least linearly, resulting in rotor blades with high efficiency and a simple structure.

[0016] The chord angle increases preferentially up to the rotor blade tip. However, the chord angle can also increase linearly from the rotor blade root to the rotor blade tip region, and more rapidly in the rotor blade tip region, which supports good start-up performance at low wind speeds.

[0017] Preferably, the chord angle is between 0° and 4° in the initial portion immediately adjacent to the root of the rotor blade, and between 20° and 26° in the tip region of the rotor blade. This results in rotor blade lengths of approximately 0.75m to approximately 4m and rotor diameters of approximately 1.5m to approximately 8m, thus producing favorable effects.

[0018] Preferably, the chord angle of the contour region at the side end of the rotor blade root is 0°.

[0019] Preferably, the trailing edge of the rotor blades is at least approximately straight. This results in a particularly simple rotor blade design.

[0020] If the trailing edge of the rotor blades extends at least approximately in the reference plane (preferably), it supports a particularly simple structure and good efficiency.

[0021] Preferably, the profile depth decreases from the rotor root toward the rotor blade tip region throughout the profile area. This keeps the mechanical stress on the rotor blades at a low level.

[0022] Preferably, the profile depth decreases continuously, and more preferably linearly. This also results in particularly simple and efficient rotor blades.

[0023] Preferably, the profile depth from the root of the rotor blade to the tip region is reduced to half to a quarter, more preferably at least about one-third. This makes the rotor blade design simple, stable, and efficient.

[0024] Preferably, the profile thickness decreases from the rotor blade root towards the rotor blade tip region over the entire profile area. This is preferably continuous, and in particular at least approximately linear. This allows the blade profile to have at least substantially the same shape throughout the entire profile area (where it is similar), resulting in a particularly simple structure.

[0025] It has been shown that, throughout the profile region, the ratio of profile thickness to profile depth is preferably at least approximately constant, resulting in a simple and efficient rotor blade. Preferably, this ratio is at least about 0.07.

[0026] Preferably, the ratio of the contour depth measured at the side end of the rotor blade root in the contour region to the length of the contour region (measured in the longitudinal direction of the rotor blade) is at least about 0.2.

[0027] The rotor blades are designed to rotate around the wind turbine's axis of rotation, which is at least generally oriented towards the direction of the wind during operation, with the rotor blades positioned on the windward side (preferably). This allows it to operate unaffected by the wind.

[0028] The blade profile is preferably a standard profile with a convex upper side and an S-shaped lower side, such that the transition from the convex shape to the concave shape on the lower side is located near the leading edge of the profile, preferably within the first 15% of the profile depth. This results in a thin blade profile.

[0029] A wind turbine equipped with such rotor blades has a rotor shaft that defines an axis of rotation and on which a hub is fixed, to which the rotor blades are attached. During wind turbine operation, the axis of rotation is at least approximately aligned with the direction of the incoming wind, and the rotor blades are positioned on the windward side to allow for undisturbed airflow.

[0030] Wind turbines preferably have two to five rotor blades, with three being particularly preferred. This ensures both a symmetrical design and smooth operation.

[0031] Preferably, the wind turbine is designed as a concealed wind turbine to achieve particularly good efficiency.

[0032] Preferably, the rotor blades are designed to extend such that their longitudinal direction is at least approximately radial to the axis of rotation. This also applies to wind turbines with two or more rotor blades, i.e., these blades are evenly distributed in the circumferential direction.

[0033] The leading edge of the rotor blade preferably extends at least substantially in a plane perpendicular to the reference plane.

[0034] The roots of the rotor blades on the hub or wind turbine shaft can also be arranged to be rotatable about a pivot axis (which extends longitudinally along the rotor blades), especially to rotate the rotor blades to a neutral position when no driving force is generated, or to optimize flow.

[0035] For completeness, it should be mentioned that during operation, the leading edge of the rotor blade is forward in the direction of rotor blade rotation, while the trailing edge of the rotor blade is backward.

[0036] Preferably, the rotor blade root is provided with two fastening lugs, which are used to fasten to the hub or wind turbine shaft, and their channels are at least approximately perpendicular to the reference plane. Attached Figure Description

[0037] The present invention has been described in more detail with reference to the accompanying drawings. These drawings are purely illustrative:

[0038] Figure 1 The rotor blades according to the present invention are shown;

[0039] Figure 2 It is based on Figure 1 A cross-sectional view of the rotor blades along the cutting line BB;

[0040] Figure 3 It is based on Figure 1 A cross-sectional view of the rotor blades along the section line CC;

[0041] Figure 4 It is based on Figure 1 A cross-sectional view of the rotor blades along the cutting line DD;

[0042] Figure 5 It is based on Figure 1 A cross-sectional view of the rotor blades along the section line EE;

[0043] Figure 6 It is based on Figure 1 A cross-sectional view of the rotor blades along the cutting line FF;

[0044] Figure 7 For along Figure 1 The direction of arrow VII Figures 1 to 6 A side view of the rotor blades;

[0045] Figure 8 For along Figure 1 The direction of arrow VIII Figures 1 to 7 A side view of the rotor blades;

[0046] Figure 9 for Figure 1 A cross-sectional view of the rotor blades along section line AA;

[0047] Figure 10 As seen from below Figures 1 to 9 The rotor blades shown;

[0048] Figure 11 For example Figures 1 to 10 The top view of the rotor blades shown;

[0049] Figure 12 for Figure 1 The rotor blades are shown in a longitudinal sectional view along the GG section line, which is perpendicular to the axis of rotation.

[0050] Figure 13 For having three bases Figures 1 to 12 A perspective view of the rotor blades of a wind turbine; and

[0051] Figure 14 To have three basis Figures 1 to 12 A perspective view of a wind turbine designed with concealed rotor blades. Detailed Implementation

[0052] like Figures 1 to 12 The rotor blade 10 shown has a rotor blade root 12 and a profile region 16 directly adjacent to the rotor blade root 12 and extending to a rotor blade tip region 13 away from the rotor blade root 12. The rotor blade 10 is designed to be fastened to a hub via the rotor blade root 12 or is designed to be fastened to a hub. The hub is rotatably fixed to a rotor shaft 18 in a known manner, the rotor shaft 18 defining an axis of rotation 20 for the rotor blade 10. Further reference is made in this regard. Figure 13 and 14 And the following related explanations.

[0053] The leading edge 22 of the front rotor blade and the trailing edge 24 of the rear rotor blade extend over the entire profile region 16 in the rotation direction D of the rotor blade 10.

[0054] In the illustrated embodiment, the contour region 16 extends to the rotor blade tip 26, that is, to the free end of the rotor blade 10. However, it is conceivable that the contour region 16 extends only into the rotor blade tip region 14, and then the rotor blade 10 has rotor blade elements of different shapes along the contour region 16 to the rotor blade tip 26.

[0055] In the contour region 16, the rotor blade 10 has a blade profile 28 that forms a suction side with its upper side 30 and a pressure side with its lower side 32 in a known manner. The blade profile 28 extends from the leading edge 22 of the rotor blade to the trailing edge 24 of the rotor blade.

[0056] exist Figure 2 In the diagram, arrow W indicates the direction of the wind flowing towards the rotor blades during operation. Therefore, the lower side 32 is located on the windward side, and the upper side 30 is located on the leeward side.

[0057] The blade profile 28 has a chord length 34 that passes through the leading edge 22 and trailing edge 24 of the rotor blade and defines a chord angle α. This chord angle α is defined by the (minimum) angle between the chord length 34 and the reference plane BE.

[0058] In the example embodiment, the reference plane BE is defined by the flat surface of the rotor blade root 12. The reference plane E further extends in the longitudinal direction L of the rotor blade 10, which extends radially relative to the rotation axis 20.

[0059] from Figure 2 As can be seen from the diagram, the reference plane BE defines the angle of attack β with respect to the rotation axis 20, which is a minimum of 50° and a maximum of 70°.

[0060] Especially from Figures 2 to 6 It can be seen that the chord angle α increases continuously over the entire profile region 16 from the rotor blade root 12 along the rotor blade tip 26 until the latter.

[0061] As shown in Figures 13 and 14, the rotor blades 10 attached to the wind turbine shaft 18 or located on the hub of the wind turbine shaft 18 are typically covered by a shaft cover 68 up to the beginning of the contoured region 16 on this side of the rotor blade (i.e., the root 12 of the rotor blade).

[0062] In the illustrated embodiment, the chord angle α immediately adjacent to the rotor blade root 12 is 0°. However, this could also be an angle of several degrees, such as up to 4°.

[0063] In the illustrated embodiment, the chord angle at the rotor blade tip is approximately 26°. However, this can also be chosen to be smaller or larger. In the rotor blade tip region 14, the chord angle α is preferably between 20° and 28°.

[0064] from Figures 2 to 6Combination Figure 1 It can be clearly seen that the chord angle α increases linearly from the rotor blade root 12 along the rotor blade tip 26.

[0065] According to Figure 1 In the view, the leading edge 22 and trailing edge 24 of the rotor blades are straight. Due to the change in chord angle α, the leading edge 22 of the rotor blades (especially from...) Figures 7 to 12 As can be seen from the image, the rotor blades exhibit a slight curve, while the trailing edge 24 (and) Figure 10 (Comparison) lies approximately in the reference plane BE over its entire length.

[0066] The profile depth 38 (i.e., the distance between the leading edge 22 and the trailing edge 24 of the rotor blade) decreases continuously from the root 12 of the rotor blade along the tip 26 of the rotor blade over the entire profile region 16.

[0067] In the illustrated embodiment example, the profile depth 38 at the rotor blade end 26 is one-third of the profile depth 38 at the end of the profile region 16 toward the rotor blade root 12.

[0068] The ratio of the contour depth 38 at the end of the contour region 16 toward the root of the rotor blade to the length of the contour region 16 (i.e., the distance between the root of the rotor blade 12 and the end of the rotor blade 26) is 0.2.

[0069] As shown linearly in the example embodiment, the profile thickness 40 also decreases continuously over the entire profile region 16 from the rotor blade root 12 to the rotor blade tip 26.

[0070] Over the entire profile region 16, the ratio of profile thickness 40 to profile depth 38 is approximately 0.07. Therefore, this is a very thin blade profile 28.

[0071] from Figures 2 to 6 As can be seen in particular, the blade profile 28 shown is a standard profile with a convex upper side 30 and an S-shaped lower side 32, wherein the transition from the convex region to the concave region on the lower side 32 is close to the rotor blade leading edge 22; the distance from the rotor blade leading edge 22 is approximately 10% of the profile depth 38.

[0072] This is especially evident from Figure 13 and Figure 14 As can be seen, the rotor blade 10 is designed to rotate around the rotation axis 20 of the wind turbine, which extends at least approximately in the direction of the wind W, and the rotor blade 10 is located on the windward side of the wind turbine.

[0073] Figure 13 and Figure 14 Both wind turbines shown are equipped with three such Figures 1 to 12The rotor blade 10 is shown and described above.

[0074] These rotor blades 10 are fixed to the hub 42 by two bolts, which are not shown, and in particular, as shown in the figure. Figure 9 As shown, each bolt engages with a fastening lug 44 at the root 12 of the rotor blade. The longitudinal direction of these fastening lugs 44 and the longitudinal direction of the bolt are perpendicular to the reference plane BE.

[0075] exist Figure 13 In the illustrated embodiment of the wind turbine, a streamlined generator housing 48 is situated on a vertical support 46, within which a generator 50 for generating electrical energy is arranged. Attached to a hub 42 are three rotor blades 10 evenly distributed circumferentially, the hub 42 being located on a wind turbine shaft 18 that drives the generator 50. A tail assembly 52 is located at the leeward end of the generator housing 48 to adjust the generator housing 48 around the vertical axis of the vertical support 46, such that the rotation axis 20 is aligned with the incoming wind 36. The rotor blade roots 12 are covered by a shaft cover 68.

[0076] Figure 14 The wind turbine embodiment shown is designed as a concealed wind turbine disclosed in document WO 2019 / 076514 A1, but the three rotor blades 10 are based on Figures 1 to 12 Designed.

[0077] Located on the vertical support 46 (rotatable about the vertical axis) is a shield 54, which is formed rotationally symmetrically about the axis of rotation 22 and has an airfoil cross-section. The inner upper surface 56 of the shield defines a flow channel 58 for the wind. The guide element 60 is annular and formed symmetrically about the axis of rotation 20. The outer diameter of the guide element 60 is smaller than the minimum clear width of the flow channel 58.

[0078] The leading edge 62 of the guide element profile is upstream relative to the leading edge 64 of the shield profile, and the trailing edge 66 of the guide element profile is downstream relative to the leading edge 64 of the shield profile, but upstream relative to the minimum net width of the flow channel 58.

[0079] The thruster with three rotor blades 10 used to drive the generator 50 is located at least approximately at the trailing edge 66 of the guide element profile.

[0080] In order to align the shield 54 and thus the axis of rotation 20 with the incoming airflow 36, the shield 54 is electrically rotatable about the axis of the vertical support 46.

[0081] The subject matter of this invention can also be limited as follows:

[0082] The rotor blade of the wind turbine has a rotor blade root 12, a profile region 16, a rotor blade leading edge 22 and a rotor blade trailing edge 24, an upper side 30 and a lower side 32, and a chord length 34. The rotor blade root 12 is used to connect the rotor blade 10 to the hub. The profile region 16 is adjacent to the rotor blade root 12 and extends to the rotor blade tip region 14 away from the rotor blade root 12. The rotor blade leading edge 22 and the rotor blade trailing edge 24 extend over the entire profile region 16. The upper side 30, which forms the suction side of the blade profile 28, and the lower side 32, which forms the pressure side of the blade profile 28, extend over the entire profile region 16 from the rotor blade leading edge 22 to the rotor blade trailing edge 24. The chord length 34 of the blade profile 28 extends through the rotor blade leading edge 22 and the rotor blade trailing edge 24. The chord angle α between the reference plane BE and the chord length 34 increases over the profile region 16 from the rotor blade root 12 toward the rotor blade tip region 14.

[0083] The reference plane BE extends along the longitudinal direction L of the rotor blade 10, and the chord length 34 at the root side of the rotor blade in the profile region 16 extends at least approximately in the reference plane BE.

[0084] The upper side 30 of the blade profile 28 is away from the reference plane BE and located on the leeward side; correspondingly, the lower side 32 is located on the windward side.

[0085] The reference plane E and the axis of rotation 20, and therefore the incoming wind, surround an angle of attack β, which is preferably between 50° and 70°.

Claims

1. A rotor blade for a wind turbine, having a rotor blade root (12), a profile region (16), a rotor blade leading edge (22) and a rotor blade trailing edge (24), an upper side (30) and a lower side (32), and a chord length (34), wherein the rotor blade root (12) defining a reference plane (BE) is used to secure the rotor blade (10) to a hub, the reference plane (BE) further extending in the longitudinal direction (L) of the rotor blade (10), the rotor blade (10) extending radially relative to a rotation axis (20), and the profile region (16) and rotor blade root (12) The rotor blade tip region (14) adjacent to and extending away from the rotor blade root (12), the rotor blade leading edge (22) and rotor blade trailing edge (24) extending over the entire contour region (16), the upper side (30) forming the suction side of the blade profile (28) and the lower side (32) forming the pressure side of the blade profile (28) extending over the entire contour region (16) from the rotor blade leading edge (22) to the rotor blade trailing edge (24), and the chord length (34) of the blade profile (28) extending through the rotor blade leading edge (22) and rotor blade trailing edge (24), characterized in that, The chord angle (α) between the reference plane (BE) and the chord length (34) increases in the profile region (16) from the rotor blade root (12) along the rotor blade end region (14).

2. The rotor blade according to claim 1, characterized in that, The chord angle (α) increases continuously.

3. The rotor blade according to claim 1 or 2, characterized in that, The chord angle (α) is between 0° and 4° in the initial portion adjacent to the rotor blade root (12), and between 20° and 28° in the rotor blade end region (14).

4. The rotor blade according to claim 1 or 2, characterized in that, The trailing edge (24) of the rotor blade extends at least in a straight line.

5. The rotor blade according to claim 1 or 2, characterized in that, The profile depth (38) decreases from the rotor blade root (12) toward the rotor blade tip region (14) over the entire profile region (16).

6. The rotor blade according to claim 5, characterized in that, The contour depth (38) decreases continuously.

7. The rotor blade according to claim 5, characterized in that, The contour depth (38) is reduced to half to a quarter.

8. The rotor blade according to claim 5, characterized in that, The contour depth (38) is reduced to one-third.

9. The rotor blade according to claim 1 or 2, characterized in that, The profile thickness (40) decreases throughout the profile region (16) from the rotor blade root (12) toward the rotor blade tip region (14).

10. The rotor blade according to claim 9, characterized in that, The profile thickness (40) decreases continuously.

11. The rotor blade according to claim 9, characterized in that, The ratio of profile thickness (40) to profile depth (38) is at least approximately constant throughout the profile region (16).

12. The rotor blade according to claim 9, characterized in that, The ratio of profile thickness (40) to profile depth (38) is at least 0.07 throughout the profile region (16).

13. The rotor blade according to claim 1 or 2, characterized in that, The rotor blades (10) are designed to rotate about the rotation axis (20) of the wind turbine, which extends at least approximately in the direction of the incoming wind (36), and the angle of attack (β) formed by the reference plane (BE) and the rotation axis (20) is at least 50°.

14. The rotor blade according to claim 1 or 2, characterized in that, The blade profile (28) is a standard profile with a convex upper side (30) and an S-shaped lower side (32).

15. A wind turbine having a rotor shaft (18) defining a rotation axis (20) and a hub (42), wherein a rotor blade (10) according to any one of claims 1 to 14 is attached to the hub (42) via its rotor blade root (12), the rotation axis (20) being at least substantially aligned with the direction of the incoming wind (36) during operation.

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