CN107893739B

CN107893739B - Blade and wind generating set

Info

Publication number: CN107893739B
Application number: CN201711350519.2A
Authority: CN
Inventors: 苏小虎; 贾少红; 樊祥希
Original assignee: Jiangsu Goldwind Science and Technology Co Ltd
Current assignee: Jiangsu Goldwind Science and Technology Co Ltd
Priority date: 2017-12-15
Filing date: 2017-12-15
Publication date: 2024-06-21
Anticipated expiration: 2037-12-15
Also published as: CN107893739A

Abstract

The invention discloses a blade and a wind generating set, wherein a noise reduction device is arranged near the rear edge of the blade (1), the noise reduction device comprises a plurality of noise reduction units (2), the noise reduction units (2) comprise a windward surface (21) and a leeward surface (22) which are connected with each other at the upper edge, and the windward surface (21) and the leeward surface (22) taper along with the extension to the two lateral sides, so that two sharp corner parts (24) are formed. The noise reduction device can effectively reduce noise generated when the blade runs.

Description

Blade and wind generating set

Technical Field

The invention relates to the field of blade noise reduction of wind generating sets, in particular to a blade with a noise reduction device and a wind generating set comprising the same.

Background

Along with the increasing capacity of the wind generating set, the capacity of the fan blade for capturing wind energy is also increased, and meanwhile, noise caused by the fan blade is increased, so that noise pollution is caused to the environment. Therefore, it is necessary to make noise reduction on the blade. In general, blade noise is mainly due to turbulent boundary layers at the blade surface and blade trailing edge elevation effects at the trailing edge portion of the blade.

Currently, noise reducers are typically installed at the trailing edge of the blade to change the direction and frequency of boundary layer vortex shedding, thereby reducing the associated noise. However, such noise reduction devices have various drawbacks, and the noise reduction effect may not be sufficiently achieved. For example, when the noise reducer is installed at the trailing edge of the blade, it is generally believed that the chord length of the blade may be increased, resulting in increased blade loads. In addition, these noise reducers may only take into account the two-dimensional flow field properties of the blade airfoil, with limited effectiveness in terms of direction and frequency of deswirled edge boundary layers of the blade, thus reducing the resultant noise reduction effect achieved.

In addition, when adopting a plurality of independent noise reduction devices to make an uproar falls, each noise reduction device need be installed alone in proper order, this makes the installation comparatively loaded down with trivial details complicacy, and the installation degree of difficulty is great.

Disclosure of Invention

According to an aspect of the present invention, there is provided a blade in which a noise reduction device is installed near a trailing edge of the blade, the noise reduction device including a plurality of noise reduction units including a windward side and a leeward side connected at an upper edge, and the windward side and the leeward side tapered as extending to both sides in a lateral direction, thereby forming two sharp corners.

Optionally, the noise reducer is mounted in a chord-wise direction of the blade at a distance of greater than 90% chord length from a foremost edge of the blade.

Optionally, the noise reduction unit is in a crescent sand dune shape, the noise reduction unit further comprises a bottom surface, the windward side, the leeward side and the bottom surface are mutually connected to form a closed three-dimensional structure, the windward side is a convex surface, the leeward side is a concave surface, and the sharp corner is formed at an intersection position among the windward side, the leeward side and the bottom surface.

Optionally, the noise reduction unit is symmetrical with respect to a central plane between the two sharp corners.

Optionally, the plurality of noise reduction units are arranged in such a manner that sharp corners of adjacent noise reduction units are in contact with each other or are separated from each other by a predetermined distance, which is less than twice the distance between two sharp corners of the noise reduction units.

Optionally, the noise reduction unit is located inside the trailing edge elevation of the blade or a portion of the noise reduction unit exceeds the trailing edge elevation.

Optionally, when a portion of the noise reduction unit exceeds the trailing edge elevation, a length of the noise reduction unit beyond the trailing edge elevation in a chord-wise direction of the blade does not exceed 30% of an overall size of the noise reduction unit.

Optionally, the noise reduction device further includes a base plate, and the plurality of noise reduction units are mounted on the blade through the base plate.

Optionally, a part of the noise reduction unit exceeds the trailing edge elevation of the blade, the bottom surface is stepped, and includes a first sub-surface, a second sub-surface and a third sub-surface, the third sub-surface is connected with the first sub-surface and the second sub-surface, the first sub-surface is mounted on one of the suction side surface and the pressure side surface of the blade, the third sub-surface and the trailing edge elevation of the blade are attached to each other, and the second sub-surface is located outside the blade and smoothly transits with the other of the suction side surface and the pressure side surface.

Optionally, the noise reduction device further comprises a base plate, and the first sub-surfaces of the noise reduction units are mounted on the blade through the base plate.

Optionally, the base plate is in the form of a wedge plate, and an edge of the base plate away from the noise reduction unit smoothly transitions with a surface of the blade.

Optionally, the substrate includes: a main body part in the form of a wedge-shaped plate, wherein the plurality of noise reduction units are arranged on the blade through the main body part, the thickness of the main body part gradually decreases along the direction from the rear edge of the blade to the front edge of the blade, the edge of the main body part far away from the noise reduction units is in smooth transition with the surface of the blade, and the edge of the main body part connected with the noise reduction units is flush with the vertical surface of the rear edge; and a filling part extending downstream from the main body part to fill a space between adjacent noise reduction units, an upper surface of the filling part smoothly transitions with an upper surface of the main body part and smoothly extends to a sharp corner of the noise reduction unit, and a lower surface of the filling part is flush with the second sub-surface.

Optionally, the substrate is connected between adjacent noise reduction units, and fills a space between facing windward sides of the adjacent noise reduction units, and sharp corners of the adjacent noise reduction units are contacted or spaced a predetermined distance.

Optionally, an angle of an intersection of the windward side and a center plane between the two sharp corners is 10-50 degrees with respect to the bottom surface.

Optionally, the angle of intersection of the leeward plane with the central plane between the two sharp corners is 20-50 degrees relative to the bottom surface.

Optionally, a distance of a highest point of an intersection line between the windward side and the leeward side from the bottom surface is 2-30mm.

Optionally, the distance between two sharp corners of the noise reduction unit is 30-300mm.

According to another aspect of the invention, a wind power plant is provided, comprising the blade described above.

The provided blade is provided with a noise reducer which can be assembled near the trailing edge of the blade in various suitable arrangements, so that the boundary layer at the elevation of the trailing edge of the blade can be effectively reduced, and the noise level generated by the blade can be remarkably reduced. The noise reduction device has a simple structure, does not increase the chord length of the blade, and is convenient to manufacture and install. At the time of installation, the noise reduction units and the base plate may be manufactured as one body by first assembling all the noise reduction units on the base plate and then assembling them together on the blade, or at the time of manufacturing the noise reduction device, so that they can be assembled on the blade at one time, whereby the assembling process can be remarkably simplified and the installation accuracy can be provided.

Drawings

FIG. 1 is a schematic structural view of a blade according to an embodiment of the present invention;

Fig. 2 is a schematic perspective view of a noise reduction unit of the noise reduction device shown in fig. 1;

FIG. 3 is a schematic view of an air flow field around the noise reduction unit shown in FIG. 2;

FIG. 4 is a cross-sectional view taken along the direction A-A of FIG. 1;

FIG. 5 is a schematic view of the installation of a noise reducer on a blade according to an embodiment of the invention;

FIG. 6 is a schematic view of the installation of a noise reducer on a blade according to an embodiment of the invention;

FIG. 7 is a schematic view of the installation of a noise reducer on a blade according to an embodiment of the invention;

FIG. 8 is a schematic view of the noise reducer of FIG. 7;

FIG. 9 is another schematic structural view of the noise reducer shown in FIG. 7;

Fig. 10 is a schematic view of the structure of the substrate shown in fig. 9;

Fig. 11 is a schematic structural view of a noise reducing device according to an embodiment of the present invention.

Reference numerals illustrate:

1: blade, 11: blade tip, 12: blade root, 13: pressure side surface, 14: suction side surface, 15: trailing edge, 16: leading edge, 17: trailing edge facade, 2: noise reduction unit, 21: windward, 22: lee side, 23: bottom surface, 231: first subsurface, 232: second subsurface, 233: a third sub-surface; 24: sharp corner, 3: substrate, 31: upper surface, 32: lower surface, 33: body portion, 34: filling part, 35: side surfaces.

Detailed Description

In order that those skilled in the art will better understand the present invention, specific embodiments thereof will be described in detail below with reference to the drawings.

Referring to fig. 1 to 4, fig. 1 is a schematic view of a vane according to an embodiment of the present invention, fig. 2 is a schematic view of a structure of a noise reduction unit of the noise reduction device shown in fig. 1, and fig. 3 is a schematic view of an air flow field around the noise reduction unit shown in fig. 2; fig. 4 is a cross-sectional view taken along the direction A-A of fig. 1.

In general, a wind park blade 1 comprises a blade tip 11 and a blade root 12 connected to a hub, while the blade 1 further comprises a leading edge 16 and a trailing edge 15, and a pressure side surface 13 and a suction side surface 14 extending between the leading edge 16 and the trailing edge 15, as shown in fig. 1. During operation of the wind power plant, noise is generated due to the turbulent boundary layer on both surfaces of the blade 1 and the blade trailing edge elevation 17, the dominant location of these noise generation being at the trailing edge 15 of the blade 1.

According to an embodiment of the invention, noise reducing means are provided on the blade 1 to change the direction and frequency of boundary layer deswirled on the pressure side surface 13 or suction side surface 14 of the blade 1, thereby reducing noise. The noise reduction device is mounted at the trailing edge 15 of the blade 1, in particular at or near the trailing edge of the blade 1, and may be located on the suction side surface 14 and/or the pressure side surface 13 of the blade 1. In particular, when installed, the noise reducing device may be installed in the chord-wise direction of the blade 1 at a location more than 90% chord-wise from the foremost edge of the blade 1, and thus at a location near the trailing edge of the blade 1, to alter the airflow field thereat to achieve noise reduction.

The noise reduction device comprises a plurality of noise reduction units 2. Fig. 2 shows a perspective view of a single noise reduction unit 2. As shown in fig. 2, the noise reduction unit 2 may include a windward side 21 and a leeward side 22, upper edges of the windward side 21 and the leeward side 22 being connected to form a substantially ridge, and the windward side 21 and the leeward side 22 tapering as they extend in a lateral direction, thereby forming two sharp corners 24 at ends where the two are connected. Here, the lateral direction refers to a direction perpendicular to the chord direction of the blade 1.

In addition to this, the noise reduction unit 2 may further comprise a bottom surface 23, the three surfaces being interconnected to form a closed three-dimensional structure, generally in the shape of a crescent-shaped sand hill, as shown in fig. 2. The noise reduction unit 2 provided by the present invention is not limited to this shape, and may take other suitable forms. The windward side 21 is a curved surface having a certain convexity, the leeward side 22 is a curved surface having a certain concavity, and the bottom surface 23 connects the windward side 21 and the leeward side 22 below. The windward side 21 may be a plane or an uneven surface. Both the windward side 21 and the leeward side 22 extend downstream with a curvature from the upstream tip end (i.e., leftmost end as shown in fig. 3) of the noise reduction unit 2, while the bottom surface 23 may be a flat surface or a curved surface adapted to the surface of the blade 1, two sharp corners 24 formed by closing the three surfaces being at the downstream-most positions, the sharp corners 24 corresponding to both wings of the noise reduction unit 2 extending in the air flow direction.

The noise reduction unit 2 may be of symmetrical construction, for example, symmetrical with respect to a central plane between the two sharp corners 24. The angle of the intersection of the windward side 21 and the central plane between the two sharp corners 24 with respect to the bottom surface 23 may be 10-50 degrees, for example, may be around 30 degrees, and the angle of the intersection of the leeward side 22 and the central plane between the two sharp corners 24 with respect to the bottom surface 23 may be 20-50 degrees, for example, may be preferably around 34 degrees. The highest point of the intersection line between the windward side 21 and the leeward side 22 may be 2-30mm from the bottom surface 23, and the distance between the two sharp corners 24 of the noise reduction unit 2 may be 30-300mm.

In fig. 3, the direction of the airflow is from left to right, the airflow P first blows towards the windward side 21, and then after passing the intersection line between the windward side 21 and the leeward side 22, a vortex tube and possibly a negative pressure zone will be formed at the downstream area of the leeward side 22, as indicated by the broken line in fig. 3. The vortex tube sucks air from the area downstream of the bottom surface 23, and as shown, the air flow in the vortex tube flows in the clockwise direction (in the orientation shown in fig. 3, seen from the lower-upper direction), and the rotation direction and the vortex intensity in each section of the vortex tube are the same, except that the rotation angular velocity corresponding to the section with the large section area is small, and the rotation angular velocity corresponding to the section with the small section area is large, so that the section area of the vortex tube tends to be infinitesimal at the two sharp corners 24 of the noise reduction unit 2, the rotation angular velocity tends to be infinite, thus forming a singular point effect, which inevitably leads to the vortex tube cracking therein, causing the phenomena of exhaust and vortex breaking. Meanwhile, since the direction of the vortex tube is substantially perpendicular to the direction of the air flow near the center position, and the direction of the vortex tube is substantially parallel to the direction of the air flow near the pointed portions 24, the direction of the vortex tube broken at the two pointed portions 24 is changed by approximately 90 ° so that the directions of the two vortices of the adjacent two noise reduction units are just opposite to cancel each other. Therefore, due to the vortex tube formed by the noise reduction unit 2, the suction effect of the vortex tube and the counteracting effect occurring when the adjacent vortex tube breaks, the boundary layer near the trailing edge elevation 17 of the vane becomes significantly smaller, thereby achieving the effect of noise reduction.

In particular assembly, as described above, the noise reducers may be mounted on the pressure side surface 13 and/or suction side surface 14 of the blade 1, i.e., may both be mounted on the pressure side surface 13 or on the suction side surface 14, or some of them may be mounted on the pressure side surface 13 and others on the suction side surface 14. For convenience of description, the following embodiment will be described taking an example in which the noise reduction device is mounted on the pressure side surface 13.

As shown in fig. 4, in one embodiment of the present invention, the noise reduction unit 2 of the noise reduction device is directly installed at the rear edge of the pressure side surface 13, the air flow flows from right to left, the windward side 21 is in an upstream position, the leeward side 22 is downstream of the windward side 21, and the bottom surface 23 is installed on the pressure side surface 13, i.e., the shape of the bottom surface 23 can be matched with the portion of the pressure side surface 13 to which it is installed. The bottom surface 23 may be glued to the pressure side surface 13 or other suitable fastening means may be used.

The noise reduction units 2 may be arranged in alignment or in a row at the trailing edge 15 of the blade 1 or may be arranged offset from each other in the direction of the air flow. For example, the noise reduction units 2 may be arranged in parallel with respect to the trailing edge elevation 17 of the blade 1, or some of the noise reduction units 2 may be closer to the trailing edge elevation 17 and some of the noise reduction units 2 may be further from the trailing edge elevation 17, although the distance from the trailing edge elevation 17 needs to be properly determined and not so far as to affect the noise reduction effect.

The adjacent two noise reduction units 2 may be disposed in contact with each other or may be disposed at a predetermined distance. For example, in the embodiment shown in fig. 5, the sharp corners 24 of adjacent noise reduction units 2 facing each other are separated by a predetermined distance L in the direction in which the trailing edge 15 of the blade 1 extends, which also needs to be suitably determined, and cannot be set too large, e.g., the predetermined distance L may be less than twice the distance between two sharp corners 24 of a noise reduction unit 2 (i.e., the length of the noise reduction unit 2) in the direction in which the trailing edge elevation 17 of the blade 1 extends. In addition, the predetermined distance L separating two adjacent noise reduction units 2 may be different from the predetermined distance between two other adjacent noise reduction units 2, that is, the noise reduction units 2 may be uniformly distributed or unevenly distributed on the pressure side surface 13, which may be specifically designed according to the noise reduction requirements.

Or in the embodiment shown in fig. 6, the sharp corners 24 of adjacent noise reduction units 2 facing each other are just in contact with each other, i.e. there is no gap between the two sharp corners 24.

It should be noted that the arrangement of the noise reduction units 2 may be combined in such a way that some of the noise reduction units 2 may be spaced apart from each other, and other noise reduction units 2 may be in contact with each other.

On the other hand, the noise reduction units 2 of the noise reduction device may also all be arranged inside the trailing edge elevation 17 of the blade 1, aligned with this trailing edge elevation 17 or beyond the trailing edge elevation 17. Of course, the noise reduction units 2 may also be arranged in any combination of these three arrangements, i.e. some of the noise reduction units 2 may be arranged inside the trailing edge facade 17, some of the noise reduction units 2 may be aligned with the trailing edge facade 17, and some of the noise reduction units 2 may extend beyond the trailing edge facade 17. Preferably, all the noise reduction units 2 may be on the same side of the trailing edge facade 17.

In case a part of the noise reduction unit 2 exceeds the trailing edge elevation 17, the length of the noise reduction unit 2 beyond the trailing edge elevation 17 in the chord-wise direction of the blade 1 does not exceed 30% of the total size of the noise reduction unit 2, or the value may be larger than 30%.

For example, as shown in fig. 4 to 6, the noise reduction units 2 are aligned with the trailing edge elevation 17 of the blade 1, i.e., the sharp corners 24 of the noise reduction units 2 are aligned with the trailing edge elevation so as to be arranged in a row as described above.

Or as shown in fig. 7, a portion of the noise reduction unit 2 extends beyond the trailing edge elevation, in which case the shape of the windward side 21 and the bottom surface 23 is changed relative to the embodiment in fig. 4 to 6. In particular, the windward side 21 may generally include a portion above the blade 1 and a portion behind the blade 1 with a step formed therebetween at the trailing edge elevation. At the same time, the line of intersection between the leeward side 22 and the bottom surface 23 is all downstream of the trailing edge elevation 17, the bottom surface 23 being substantially divided into sections, comprising a first sub-surface 231, a second sub-surface 232 and a third sub-surface 233, which may be substantially stepped with respect to each other, the steps being at the trailing edge elevation 17 of the blade 1. The first sub-surface 231 is mounted on the pressure side surface 13 of the blade 1, while the second sub-surface 232 is downstream of the trailing edge elevation and may smoothly transition or be flush with the suction side surface 14, and the third sub-surface 233 is between the first sub-surface 231 and the second sub-surface 232 and may be in close proximity to the surface at the trailing edge elevation of the blade, in order to mount the noise reduction unit 2 on the blade 1 with a portion thereof beyond the trailing edge elevation of the blade 1.

Each noise reduction unit 2 may be mounted directly on the pressure side surface 13 of the blade 1 as shown in fig. 4, or may be mounted on the pressure side surface 13 by other means as shown in fig. 7.

On the basis of the embodiments described above with reference to fig. 1 to 6, the noise reduction device further comprises a base plate 3, by means of which base plate 3 the noise reduction unit 2 can be mounted on the surface of the blade 1.

The base plate 3 may be mounted regardless of how the noise reduction unit 2 is arranged and mounted with respect to the surface of the blade 1. That is, in the case where the noise reduction unit 2 shown in fig. 1 to 6 is inside the trailing edge elevation 17 or aligned, the substrate 3 may also be mounted between the noise reduction unit 2 and the blade 1. In the embodiment of the noise reduction unit 2 shown in fig. 7, where a part of the noise reduction unit 2 extends beyond the trailing edge elevation 17, a part of the noise reduction unit 2 is located on the base plate 3 and another part is located outside the blade 1.

In fig. 7, the substrate 3 is mounted between the first sub-surface 231 and the pressure side surface 13. In this case, when the base plate 3 is added, the arrangement of the noise reduction units 2 on the surface of the blade 1 is not affected, and may be arranged in various ways as described above with reference to fig. 1 to 6, and only the base plate 3 is further installed between each noise reduction unit 2 and the blade 1. Since the noise reduction units 2 are arranged in a plurality of arrangements, and may be arranged in a combined arrangement, the noise reduction units 2 may be divided into a plurality of groups according to the arrangement, for example, the noise reduction units 2 arranged in the same manner and close to each other may be grouped into one group, and the noise reduction units of the group may be mounted using one substrate 3. Of course, if the arrangement of all the noise reduction units 2 allows, it is also possible to mount all the noise reduction units 2 on the blade 1 using a single base plate 3.

A portion of the base plate 3 may be upstream of the noise reduction unit 2. The lower surface 32 of the base plate 3 is mounted on the pressure side surface 13, for example, by bonding or other suitable means. The base plate 3 may be substantially in the form of a wedge-shaped plate, the thickness of which decreases gradually in a direction opposite to the direction of the air flow, i.e. the sharp edge of the wedge-shaped plate is at the most upstream, and the upper surface 31 of the base plate 3 may smoothly transition with the pressure side surface 13 to avoid that there is a sharp bond between the base plate 3 and the blade 1 affecting the distribution of the air flow field and the noise reduction effect, and the upper surface 31 is smoothly transitioned everywhere without sharp corner transition.

In mounting the noise reduction device to the blade 1, all the noise reduction units 2 may be assembled to the base plate 3 first, and then the assembly formed by the two may be assembled to the blade 1. In the preferred embodiment, the base plate 3 and the noise reduction units 2 may be manufactured as one body, so that the operation of sequentially installing the respective noise reduction units 2 can be omitted at the time of assembly, thereby significantly simplifying the transportation and assembly of the noise reduction device, and the alignment (if such an arrangement is adopted) relationship of the noise reduction units 2 with each other can also be ensured at the time of assembly, without having to be manually aligned at the time of installation, thereby ensuring the noise reduction effect.

Any suitable substrate form may be employed. For example, when the sharp corner 24 of the noise reduction unit 2 is aligned with the trailing edge elevation 17 after installation and is entirely on the blade 1, the base plate 3 may also be entirely on the blade 1 and be in the form of a generally rectangular wedge-shaped plate, with the edge (or upstream edge) of the base plate 3 remote from the noise reduction unit 2 smoothly transitioning with the blade surface, while the edge (or downstream edge) connected with the noise reduction unit 2 may be aligned with the trailing edge elevation 17.

When the noise reduction unit 2 is mounted beyond the trailing edge elevation 17, the base plate 3 may be in the form of a generally rectangular wedge plate, as shown in fig. 8. The edge of the base plate 3 (or downstream edge) which is connected to the noise reduction unit 2 is aligned with the trailing edge elevation 17, i.e. the base plate 3 is entirely on the blade 1. Although the adjacent noise reduction units 2 are shown in fig. 8 to be separated by a predetermined distance, the substrate 3 shown in fig. 8 may be used for an embodiment in which the adjacent noise reduction units 2 are in contact with each other.

In addition, as shown in fig. 9, a portion of the substrate 3 extends beyond the trailing edge elevation 17. Specifically, the substrate 3 may include a main body portion 33 and a filling portion 34, as shown in fig. 10. The shape of the main body portion 33 may be similar to the shape of the substrate shown in fig. 8, i.e., between the first sub-surface 231 of the noise reduction unit 2 and the pressure side surface 13, the thickness thereof gradually decreases in a direction from the trailing edge 15 to the leading edge 16 of the blade 1, and an edge (or downstream edge) of the main body portion 33 connected to the noise reduction unit 2 is flush with the trailing edge elevation 17, an edge (or upstream edge) of the main body portion 33 remote from the noise reduction unit 2 and an upper surface smoothly transition with the pressure side surface 13, and a lower surface may be adhered on the pressure side surface 13. The filling portion 34 extends downstream from the main body portion 33 and fills the space between adjacent noise reduction units 2. The upper surface of the filling portion 34 smoothly transitions with the upper surface of the main body portion 33 and may smoothly extend downstream to finally extend to the sharp corner portion 24 of the noise reduction unit 2, thereby completely filling the space between adjacent noise reduction units 2 and further avoiding forming holes between the vane 1 and the adjacent two noise reduction units 2 to reduce noise reduction effect. The lower surface of the filling portion 34 may be flush with the second sub-surface 232 of the noise reduction unit 2. The main body portion 33 and the filling portion 34 are preferably of unitary construction. By providing the substrate 3 with the filling portion 34, the air flow field around the noise reduction device can be smoother, the boundary layer at or behind the trailing edge elevation 17 of the blade can be further reduced, and the noise reduction effect can be enhanced. Although the adjacent noise reduction units 2 shown in fig. 9 are in contact with each other, the substrate shown in fig. 9 may be used for an embodiment in which the adjacent noise reduction units 2 are spaced apart by a predetermined distance.

In addition, as shown in fig. 11, the substrate 3 is connected between adjacent noise reduction units 2, and fills the space between the facing windward sides 21 of the adjacent noise reduction units 2. Specifically, the side surface 35 of the base plate 3 is located between the intersection line between the center face and the windward face 21 of the adjacent noise reduction units 2, and the side surface 35 may be a plane. The upper surface 31 of the base plate 3 extends along or is aligned with the intersection of the windward and leeward sides 21, 22 of the noise reduction unit 2. The lower surface 32 of the base plate 3 may extend in alignment with the bottom surface 23 of the noise reduction unit 2. It should be noted that, although in fig. 11, adjacent noise reduction units 2 are shown contacting each other and a portion of the noise reduction units 2 extends beyond the trailing edge 15 of the blade 1, the illustrated base plate 3 is equally applicable to a case where adjacent noise reduction units 2 are spaced apart by a predetermined distance, and is also equally applicable to a case where the noise reduction units 2 are entirely on the pressure side surface 13 of the blade 1 (including two embodiments where the most downstream sharp corner 24 of the noise reduction units 2 is aligned with or inside the trailing edge elevation).

In addition, the sizes of the noise reduction units 2 of the noise reduction device may be different, for example, some of the noise reduction units 2 may be designed to be larger and some of the noise reduction units 2 may be designed to be smaller according to the airflow field distribution behind the trailing edge 15 of the blade 1.

According to the noise reduction device provided by the invention, the noise reduction device can be conveniently assembled near the rear edge of the blade, the boundary layer at the vertical face of the rear edge of the blade can be effectively reduced, and the noise level generated by the blade is remarkably reduced. Meanwhile, the assembly of the noise reduction device can be remarkably simplified through the base plate 3, and the operation efficiency is improved.

In addition, according to an embodiment of the present invention, there is also provided a wind power generation set including the above-described blade 1, on which the above-described noise reduction device can be mounted on the blade 1, and a similar noise reduction effect can be achieved.

While certain embodiments have been shown and described, it would be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A blade characterized in that a noise reduction device is installed near a trailing edge (15) of the blade (1), the noise reduction device comprising a plurality of noise reduction units (2), the noise reduction units (2) comprising a windward side (21) and a leeward side (22) connected at an upper edge, and the windward side (21) and the leeward side (22) tapering as extending to both sides in a lateral direction so as to form two sharp corners (24), the plurality of noise reduction units (2) being arranged in such a manner that the sharp corners (24) of adjacent noise reduction units (2) are in contact with each other or are separated by a predetermined distance, the predetermined distance being less than twice the distance between the two sharp corners (24) of the noise reduction units (2),

The noise reduction device further comprises a substrate (3), the substrate (3) comprising:

-a body portion (33) in the form of a wedge-shaped plate, said plurality of noise reduction units (2) being mounted on said blade (1) by means of said body portion (33), the thickness of said body portion (33) gradually decreasing in the direction from the trailing edge (15) of said blade (1) to the leading edge (16) of said blade (1), the edge of said body portion (33) remote from said noise reduction units (2) smoothly transitioning with the surface of said blade (1), the edge of said body portion (33) connected with said noise reduction units (2) being flush with the trailing edge elevation (17) of said blade (1);

A filling portion (34) extending downstream from the main body portion (33) to fill a space between adjacent noise reduction units (2), an upper surface of the filling portion (34) smoothly transitions with an upper surface of the main body portion (33) and smoothly extends to a sharp corner (24) of the noise reduction unit (2), and a lower surface of the filling portion (34) is flush with a second sub-surface (232) of a bottom surface (23) of the noise reduction unit (2); or alternatively, the first and second heat exchangers may be,

The base plates (3) are connected between adjacent noise reduction units (2) and fill spaces between facing windward sides (21) of the adjacent noise reduction units (2), and sharp corners (24) of the adjacent noise reduction units (2) are in contact with or spaced apart from each other by a predetermined distance.

2. A blade according to claim 1, characterized in that the noise reducing device is mounted in the chord-wise direction of the blade (1) at a distance of more than 90% chord-wise from the foremost edge of the blade (1).

3. Blade according to claim 1, characterized in that the noise reduction unit (2) is in the form of a crescent sand dune, the noise reduction unit (2) further comprising a bottom surface (23), the windward side (21), the leeward side (22) and the bottom surface (23) being connected to each other forming a closed three-dimensional structure, the windward side (21) being convex, the leeward side (22) being concave, the sharp corner (24) being formed at the intersection between the windward side (21), the leeward side (22) and the bottom surface (23).

4. Blade according to claim 1, characterized in that the noise reduction unit (2) is symmetrical with respect to a central plane between two sharp corners (24).

5. Blade according to claim 1, characterized in that the noise reduction unit (2) is located inside the trailing edge elevation (17) of the blade (1) or a part of the noise reduction unit (2) exceeds the trailing edge elevation (17).

6. A blade according to claim 5, characterized in that, when a part of the noise reduction unit (2) exceeds the trailing edge elevation (17), the length of the noise reduction unit (2) exceeding the trailing edge elevation (17) in the chord direction of the blade (1) does not exceed 30% of the total size of the noise reduction unit (2).

7. A blade according to any one of claims 1 to 6, characterized in that the noise reduction device further comprises a base plate (3), the plurality of noise reduction units (2) being mounted on the blade (1) by means of the base plate (3).

8. A blade according to claim 3, characterized in that a part of the noise reduction unit (2) extends beyond the trailing edge elevation (17) of the blade (1), the bottom surface (23) being stepped, comprising a first sub-surface (231), a second sub-surface (232) and a third sub-surface (233), the third sub-surface (233) connecting the first sub-surface (231) and the second sub-surface (232), the first sub-surface (231) being mounted on one of the suction side surface (14) and the pressure side surface (13) of the blade, the third sub-surface (233) being in abutment with the trailing edge elevation (17) of the blade (1), the second sub-surface (232) being outside the blade and smoothly transitioning with the other of the suction side surface (14) and the pressure side surface (13).

9. A blade according to claim 8, characterized in that the first sub-surface (231) of the plurality of noise reduction units (2) is mounted on the blade (1) by means of the base plate (3).

10. Blade according to claim 9, characterized in that the base plate (3) is in the form of a wedge-shaped plate, the edge of the base plate (3) remote from the noise reduction unit (2) transitioning smoothly with the surface of the blade (1).

11. A blade according to claim 3, characterized in that the angle of the intersection of the windward side (21) and the centre plane between the two sharp corners (24) is 10-50 degrees relative to the bottom surface (23).

12. A blade according to claim 3, characterized in that the angle of the intersection of the leeward surface (22) with the centre plane between the two sharp corners (24) is 20-50 degrees relative to the bottom surface (23).

13. A blade according to claim 3, characterized in that the highest point of the intersection between the windward side (21) and the leeward side (22) is at a distance of 2-30mm from the bottom surface (23).

14. Blade according to claim 1, characterized in that the distance between two sharp corners (24) of the noise reduction unit (2) is 30-300mm.

15. A wind power plant comprising a blade according to any of claims 1 to 14.