Blade vibration suppression device and blade assembly

Abstract

The disclosed embodiment provides a blade vibration suppression device and a blade assembly. The blade vibration suppression device is made of a flexible material, including a sheet-like region and a strip-like region integrally connected to the sheet-like region. The strip-like region and the sheet-like region are enclosed to form a ring, so that they can be sleeved on the blade. The sheet-like region can be enclosed on one side of the blade to form a wind bag. Under the action of external wind, the wind bag can be opened, thereby increasing the damping of the blade. By arranging a blade vibration suppression device made of a flexible material on the blade, including a sheet-like region and a strip-like region connected to the sheet-like region, the wind bag enclosed by the sheet-like region can be opened under the action of external wind, so that the damping of the blade can be increased, thereby solving the problem of yard vibration caused by strong winds.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wind power generation, and in particular to a blade vibration suppression device and a blade assembly. Background Art

[0002] The blades of large turbine units are sometimes stored in large quantities in the yard before being hoisted. Under certain wind conditions (such as high wind speed, wind direction perpendicular to the span direction), the blades will cause first-order vibration in the swing direction. When the vibration amplitude is large, it will cause the blades to touch the ground, causing damage to the blade shape and structure or even scrapping; in addition, long-term and large-scale vibration will also cause fatigue load damage in this direction. At present, the main solution is to set a mesh sleeve on the blade tip. The blade tip mesh sleeve can change the aerodynamic performance of the blade, produce a turbulent effect on the blade surface, and achieve vibration suppression of the blade.

[0003] However, the mesh vibration suppression scheme has the following disadvantages: first, the reliability is insufficient and the efficiency is low, and the mesh usually needs to be installed over a large area of ​​the blade; especially at high wind speeds, the vibration suppression effect cannot be guaranteed, and in actual applications it is usually necessary to cooperate with the anchor fixation method; second, the cost is high and it is not convenient to transport. The mesh itself has the characteristics of customization and large material consumption, resulting in high cost; in addition, the mesh itself is large in size and not convenient to transport, resulting in high transportation cost; third, the mesh interferes with pneumatic accessories. Currently, most blades are equipped with pneumatic accessories such as VG (vortex generator). Taking VG as an example, the installation range of VG is usually 80-90% from the blade root to the blade extension, which is also the installation range of the mesh. Therefore, it will interfere with the mesh, causing damage to the VG and difficulty in disassembly and installation of the mesh. Summary of the invention

[0004] The present disclosure aims to at least solve the problem in the above-mentioned prior art or related technology that blade vibration can easily cause damage to the blade shape and structure or even cause it to be scrapped, and can avoid the existing defects of suppressing vibration by setting a mesh sleeve on the blade, such as insufficient reliability, high cost, and interference between the mesh sleeve and pneumatic accessories.

[0005] To achieve the above-mentioned purpose, a first aspect embodiment of the present disclosure provides a blade vibration suppression device for installation on the blades of a wind turbine generator set. The blade vibration suppression device is made of a flexible material, and includes a sheet-like area and a strip-like area integrally connected to the sheet-like area. The strip-like area and the sheet-like area are enclosed to form a ring so that they can be sleeved on the blade. The sheet-like area can enclose one side of the blade to form a wind bag. Under the action of external wind, the wind bag can open, thereby increasing the damping of the blade.

[0006] A second aspect of the present disclosure provides a blade assembly, which includes a blade and a blade vibration suppression device as described in the above embodiment, wherein the blade vibration suppression device is sleeved on the tip region of the blade.

[0007] The blade vibration suppression device and blade assembly provided in the embodiment of this aspect are based on the characteristic that wind resistance is positively correlated with wind speed. A blade vibration suppression device is arranged on the blade, so that the damping of the blade is increased under the action of the blade vibration suppression device, thereby solving the problem of yard vibration caused by strong winds, thereby avoiding damage to the blade appearance or even scrapping of the blade structure caused by blade vibration. At the same time, the blade vibration suppression device is made of flexible material, specifically including a sheet area and a strip area integrally connected to the sheet area. The integrated design has a small volume, is easy to install and transport, and has low cost. Moreover, during the vibration suppression process, the external wind blows open the windbag, separates the sheet area from the blade, and can reduce the probability of interference with pneumatic accessories. In addition, the application scenarios of the present invention include but are not limited to the storage of blades in the yard, before the blades are connected to the grid after hoisting, and shutdown maintenance conditions during the operation of the blades.

[0008] Additional aspects and / or advantages of the present general inventive concept will be set forth in part in the following description and in part will be obvious from the description, or may be learned through practice of the present general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other objects and features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings which exemplarily illustrate an example, in which:

[0010] Figure 1 is a schematic structural diagram of a blade vibration suppression device according to an embodiment of the present invention installed on the trailing edge side of a blade;

[0011] Figure 2 is a partial structural schematic diagram of a blade vibration suppression device installed on the trailing edge side of a blade according to an embodiment of the present invention;

[0012] Figure 3 is a schematic structural diagram of a blade vibration suppression device according to an embodiment of the present invention after being blown up;

[0013] Figure 4 is a schematic diagram of a verification result of a blade vibration suppression effect of a blade vibration suppression device according to an embodiment of the present invention;

[0014] Figure 5 is a single fixed vibration direction stall-induced flutter model according to an embodiment of the present invention;

[0015] Figure 6 is an arbitrary vibration direction stall-induced flutter model according to an embodiment of the present invention;

[0016] Figure 7 is a simulation diagram of the effect of a blade vibration suppression device on a flow field on a blade surface according to an embodiment of the present invention;

[0017] Figure 8 is another simulation diagram of the effect of the blade vibration suppression device on the flow field on the blade surface according to one embodiment of the present invention;

[0018] Fig. 9 and Fig.10 Schematic diagrams showing the results of damping calculation using field parameters on a blade without the blade vibration suppression device of the present invention installed and a blade with the blade vibration suppression device of the present invention installed are shown respectively.

[0019] Figures 1 to 10 Description of reference numerals:

[0020] 10 sheet areas, 110 wind bags,

[0021] 20 belt area, 210 connecting belt,

[0022] 30 blades, 310 suction side, 320 pressure side, 330 trailing edge side, 340 leading edge side. DETAILED DESCRIPTION

[0023] The following specific embodiments are provided to help the reader gain a comprehensive understanding of the methods, devices and / or systems described herein. However, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be clear after understanding the disclosure of the present application. For example, the order of operations described herein is only an example and is not limited to those orders set forth herein, but can be changed as will be clear after understanding the disclosure of the present disclosure, except for operations that must occur in a specific order. In addition, for greater clarity and simplicity, descriptions of features known in the art may be omitted.

[0024] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided to illustrate only some of the many possible ways to implement the methods, devices, and / or systems described herein, which will be clear after understanding the disclosure of the present disclosure.

[0025] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more.

[0026] Although terms such as "first", "second", and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions should not be limited by these terms. Instead, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, first component, first region, first layer, or first portion referred to in the examples may also be referred to as the second member, second component, second region, second layer, or second portion.

[0027] In the specification, when an element such as a layer, a region or a substrate is described as being “on”, “connected to” or “coupled to” another element, the element may be directly “on”, “connected to” or “coupled to” another element, or one or more other elements may be present therebetween. Conversely, when an element is described as being “directly on”, “directly connected to” or “directly coupled to” another element, other elements may not be present therebetween.

[0028] The terms used herein are only used to describe various examples and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "comprise", "include" and "have" indicate the presence of the described features, quantities, operations, components, elements and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements and / or combinations thereof. The term "plurality" represents any number of two and more than two.

[0029] The definitions of directional terms such as "upper", "lower", "top" and "bottom" in the present disclosure are all based on the definitions of the orientations of the components in the drawings.

[0030] Unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meaning as those generally understood by ordinary technicians in the field to which the present invention belongs after understanding the present invention. Unless explicitly defined as such herein, terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant field and the present invention, and should not be interpreted in an idealized or overly formal way.

[0031] Furthermore, in the description of the examples, when it is considered that a detailed description of a well-known related construction or function will cause vague interpretation of the present invention, such a detailed description will be omitted.

[0032] The following will be combined Figures 1 to 8The blade vibration suppression device and blade assembly provided by the embodiments of the present disclosure can solve the vibration problem of the yard caused by strong winds. Of course, the application scenarios of the present invention include but are not limited to the storage of blades 30 in the yard, the blades 30 after hoisting and before grid connection, and the maintenance of the blades 30 during operation.

[0033] like Figures 1 to 3 As shown, a first aspect embodiment of the present disclosure provides a blade vibration suppression device for installation on a blade 30 of a wind turbine generator set. The blade vibration suppression device is made of a flexible material, and includes a sheet region 10 and a strip region 20 integrally connected to the sheet region 10. The strip region 20 and the sheet region 10 are enclosed to form a ring so that they can be sleeved on the blade 30. The sheet region 10 can enclose one side of the blade 30 to form a wind bag 110. Under the action of external wind, the wind bag 110 can open, thereby increasing the damping of the blade 30.

[0034] The blade vibration suppression device and blade assembly provided in the embodiment of this aspect are based on the characteristic that wind resistance is positively correlated with wind speed. A blade vibration suppression device is arranged on the blade 30 so that the damping of the blade 30 is increased under the action of the blade vibration suppression device, thereby solving the problem of yard vibration caused by strong winds, thereby preventing the vibration of the blade 30 from causing damage to the appearance of the blade 30 or even the structural scrapping of the blade 30.

[0035] Specifically, when the blade vibration suppression device is sleeved within the blade tip range of the blade 30, refer to Figure 2 When the wind blows from the strip area 20 to the sheet area 10, the sheet area 10 is blown open to form a bulge (i.e., the wind bag 110 is opened, see Figure 3 The flap area 10 blocks the flow of wind and destroys the free flow in the blade tip area. On the one hand, the damping of the blade 30 is increased and the lift is reduced, which is conducive to suppressing the stall flutter of the blade 30. On the other hand, a pressure difference is formed on both sides of the flap area 10, so that the flap area 10 can apply a backward pulling force roughly consistent with the vibration direction of the blade to the blade 30, thereby suppressing the vibration of the blade 30.

[0036] It is worth noting that since the relationship between wind resistance and wind speed is a quadratic positive correlation, the greater the wind speed, the greater the increased damping. By setting the sheet area 10, the wind resistance can be efficiently utilized to increase the damping of the blade 30 and avoid stall-induced flutter of the blade 30.

[0037] In addition, since the blade vibration suppression device is made of a flexible material, specifically including a sheet region 10 and a strip region 20 integrally connected to the sheet region 10, the integrated design facilitates installation, and can be stacked when not in use without taking up extra space, and has the characteristics of being small in size, easy to store and transport, and reusable. The flexible sheet region 10 and strip region 20 are not easily damaged, and common materials can be selected to reduce costs. In addition, the sheet region 10 and the strip region 20 integrally connected thereto are sleeved on the blade 30, and the contact area between the strip region 20 and the blade 30 is very small compared to the sheet region 10, and its influence on the aerodynamic shape of the blade 30 can be ignored. The wind bag 110 surrounded by the sheet area 10 can be blown away from the blade 30 in the working state, which can increase the damping of the blade 30 without changing the aerodynamic shape and aerodynamic performance of the blade 30, and reduce the probability of interference with pneumatic accessories, thereby eliminating the problem of easy interference with pneumatic accessories such as VG (vortex generator) in the related technology, causing damage to VG and difficulty in installation and removal of the net. In addition, the flexible material does not need to consider the shape, has good adaptability, can be reused on different blade 30 models, and has good versatility.

[0038] In addition, it should be noted that the sheet-like region 10 can enclose a wind bag 110 on the side where the blade 30 is located. The shape of the wind bag 110 here is not strictly bag-shaped. The sheet-like region 10 opens to form a bulge under the action of wind. The bulge can also be used as the wind bag 110. As long as the wind can be realized and the damping of the blade 30 is increased, it is in line with the inventive concept of this embodiment. The shape of the wind bag 110 is not strictly limited here. Moreover, the sheet-like region 10 can be enclosed to form a wind bag 110 on the side where the blade 30 is located in a natural state (for example, when there is no wind or the wind is very small), or it can be blown up under the action of wind, and then enclosed to form a wind bag 110 on the side where the blade 30 is located. Here, it is mainly shown that the sheet-like region 10 can be enclosed to form a wind bag 110 on the side where the blade 30 is located, and the wind bag 110 can be opened under the action of external wind to realize the increase of the damping of the blade 30, which is in line with the inventive concept of this application.

[0039] As for the integrated connection of the sheet region 10 and the strip region 20, further, in some embodiments, the sheet region 10 and the corresponding strip region 20 are made of the same piece of flexible material. This facilitates production and processing, reduces the number of stitching steps, and reduces production costs. In addition, due to the small number of stitching connections, the probability of the blade vibration suppression device being blown apart by strong winds can also be reduced, especially at the stitching connection.

[0040] As an example, making the sheet area 10 and the strip area 20 seamlessly connected can effectively prevent the adjacent positions of the two from being blown apart or cracked by strong winds, resulting in the sheet area 10 being loosely connected or even detached from the blade 30 and failing to suppress vibration.

[0041] Here, the sheet-like region 10 and the corresponding strip-like region 20 are made of the same piece of flexible material. The flexible material can be made into a ring-like structure in advance, and then the blade vibration damping device cut out can be seamlessly connected as a whole. The sheet-like region 10 and the corresponding strip-like region 20 can also have a suture connection line in the circumferential direction of the blade 30. In this case, the flexible material can be roughly sheet-like. After cutting out the sheet-like region 10 and the strip-like region 20, they are sutured together to form a ring, which is convenient for sleeves on the blade 30. For example, one end of the strip-like region 20 is directly connected to one end of the sheet-like region 10 without sewing, and the other end of the strip-like region 20 is sutured to the other end of the sheet-like region 10, and they are enclosed in a ring and sleeved on the blade 30. For another example, the cut strip-like region 20 is divided into two sections, one end of each section is directly connected to the sheet-like region 10 without sewing, and the other end of each section is sutured together to form a ring with the sheet-like region 20.

[0042] In other embodiments, the sheet region 10 and the corresponding strip region 20 are sewn together. Here, the sheet region 10 and the corresponding strip region 20 are made of the same flexible material, or they can be made of different flexible materials. For example, the material hardness of the strip region 20 is greater than the material hardness of the sheet region 10, the material elasticity of the sheet region 10 is greater than the material elasticity of the strip region 20, and the material weight of the sheet region 10 is less than the material weight of the strip region 20, etc., which is conducive to ensuring that the blade vibration suppression device is stably installed on the blade 30, while making the wind bag 110 have a better wind effect.

[0043] In some embodiments, the blade vibration suppression device includes a plurality of sheet-shaped regions 10 and corresponding strip-shaped regions 20 , and a plurality of air bags 110 can be arranged in sequence along the span direction of the blade 30 .

[0044] In these embodiments, multiple air bags 110 are arranged in the span direction of the blade 30 for air circulation, which expands the air circulation range and can better increase the damping of the blade 30, thereby improving the vibration suppression effect. At the same time, the length of each sheet area 10 can also be reduced to avoid the length of a single air bag 110 being too long and increasing the difficulty of installation. Based on the method of increasing damping by flexible materials, the air bag 110 will be subject to great aerodynamic resistance, so the solution of using an integral air bag 110 will have high requirements for component strength, while the installation of this embodiment adopts the form of breaking the whole into parts, and using multiple air bags 110 can disperse the force and improve the reliability of the components.

[0045] Furthermore, multiple air bags 110 can be arranged continuously along the span direction of the blade 30. Compared with using a whole large sheet area 10 to form a large air bag 110 for air, using multiple air bags 110 that are integrated and adjacent to each other for air will not cause the sheet area 10 to be blown over or even completely fly away under the action of the wind. Moreover, each sheet area 10 and the corresponding strip area 20 are matched and sleeved on the blade 30, and the connection is stable and reliable.

[0046] In this case, the plurality of air bags 110 can be made of the same piece of flexible material, that is, the plurality of sheet regions 10 can be made of the same piece of flexible material. Figure 2 There is no seamless connection line between the multiple sheet regions 10. In this case, multiple sheet regions 10 with air bags 110 can be directly woven when weaving or preparing the flexible material. For another example, in addition to being connected together by the material itself, the two sides of each sheet region 10 are sewn together to form an air bag 110, and two adjacent air bags 110 are separated by a sewing connection line. In this case, there is no need to restrict the initial shape of the flexible material too much, and a variety of flexible materials can be selected to make the blade vibration suppression device.

[0047] Of course, in this case, the air bags 110 can also be sewn together, that is, two adjacent sheet regions 10 are sewn together, so that multiple air bags 110 can be continuously arranged along the span direction of the blade 30. At this time, the materials of the multiple sheet regions 10 can be the same or different.

[0048] Alternatively, a plurality of air bags 110 may be arranged at intervals along the span direction of the blade 30 .

[0049] Regarding the structure of the band-shaped region 20, further, in some embodiments, each sheet-shaped region 10 has at least one connecting band 210 in the corresponding band-shaped region 20. The number of connecting bands 210 can be increased or decreased according to the desired vibration suppression effect.

[0050] As an example, the strip region 20 corresponding to each sheet region 10 includes a first connecting belt 210 and a second connecting belt 210, and the first connecting belt 210 and the second connecting belt 210 connect the two ends of the sheet region 10 in the direction of the blade 30. On the one hand, it is convenient for wind to blow into the sheet region 10 from between the two connecting belts 210, and the sheet region 10 swells under the action of the wind, and the wind bag 110 opens; on the other hand, the two connecting belts 210 can limit the sheet region 10, and can pull the two ends of the sheet region 10 blown by the wind, so as to facilitate the enclosed formation of the wind bag 110 shape.

[0051] As an example, in the case where the blade vibration suppression device includes a plurality of sheet-shaped regions 10 and corresponding strip-shaped regions 20, and a plurality of air bags 110 are continuously arranged along the span direction of the blade 30, refer to Figure 1 and Figure 2 , the air bags 110 at the two ends of the multiple air bags 110 can be connected to a connecting belt 210, and the same connecting belt 210 can be connected between two adjacent air bags 110. Reduce the material usage and save costs. Among them, at least the connecting belts 210 at the two ends of the blade 30 in the span direction are connected to the blade 30 to limit the movement of the blade vibration suppression device along the span direction of the blade 30 and improve the connection stability of the blade vibration suppression device. The sheet area 10 opens to form a bulge under the action of wind to block the flow of airflow. At this time, the wind force received by the sheet area 10 can be transmitted to the blade 30 by the connecting belt 210 in the middle, reducing the vibration amplitude of the blade 30. That is, the connecting belts 210 at the two ends can mainly play the role of limiting the movement of the sheet area 10 along the span direction of the blade 30, and the connecting belt 210 in the middle can mainly play the role of transmitting the pressure difference on both sides of the sheet area 10 to the blade 30.

[0052] As for the connection method between the blade vibration damping device and the blade 30, further, in some embodiments, the ring formed by the band area 20 and the sheet area 10 has a certain tension force, which can be tightly sleeved on the blade 30 and make the wind bag 110 in a relaxed state in a natural state. That is, the flexible material has a certain tension. The installation is convenient and quick, and no additional connectors are required or only a small number of connectors are used to connect the blade vibration damping device and the blade 30, reducing parts and saving costs.

[0053] In other embodiments, the band region 20 is fixed to the blade 30 by a strapping belt, and the air bag 110 is in a relaxed state in a natural state. Here, the band region 20 and the blade 30 are directly connected by a strapping belt, which is convenient for operation.

[0054] Furthermore, in some embodiments, the opening of the air bag 110 faces the leading edge side 340 or the trailing edge side 330 of the blade 30. Figures 1 to 3 As shown, the opening of the air bag 110 faces the leading edge side 340 of the blade 30. Of course, when multiple air bags 110 are arranged in the span direction of the blade 30, the openings of the multiple air bags 110 may all face the leading edge side 340 of the blade 30, or may all face the trailing edge side 330 of the blade 30, or may partly face the leading edge side 340 of the blade 30 and partly face the trailing edge side 330 of the blade 30, so that the vibration suppression effect can be exerted no matter from which direction the external wind blows.

[0055] Further, in the span direction of the blade 30, a plurality of sheet-like regions 10 are arranged continuously. Figure 2 and Figure 3, the plurality of sheet-like regions 10 may all be close to the trailing edge side 330 of the blade 30, and the opening of the air bag 110 may face the leading edge side 340 of the blade 30. Or the plurality of sheet-like regions 10 may all be close to the leading edge side 340 of the blade 30, and the opening of the air bag 110 may face the trailing edge side 330 of the blade 30.

[0056] Alternatively, each sheet region 10 and the strip region 20 are alternately arranged in the span direction of the blade 30. For example, there is a strip region 20 between two adjacent sheet regions 10 in the span direction of the blade 30, and in the two adjacent sheet regions 10, the opening of one air bag 110 faces the leading edge side 340 of the blade 30, and the opening of the other air bag 110 faces the trailing edge side 330 of the blade 30. Thus, no matter which direction the external wind blows from, the vibration suppression effect can be exerted.

[0057] Or further, two sheet areas 10 are relatively arranged at the same position in the span direction of the blade 30, the openings of the two wind bags 110 are relatively distributed, and the strip area 20 and the sheet area 10 can be partially cross-overlapped, which can effectively prevent vibration when wind blows from two directions.

[0058] Furthermore, in some embodiments, Figure 3 As shown, at least a portion of the air bag 110 is located on the suction side 310 of the blade 30 , so as to reduce the flow velocity of the airflow flowing through the suction side 310 of the blade 30 .

[0059] Normally, when the airflow flows through the periphery of the blade 30, the airflow velocity on the suction side 310 of the blade 30 is greater than the airflow velocity on the pressure side 320 of the blade 30. According to the Bernoulli equation, the greater the gas flow rate, the smaller the pressure. Therefore, the pressure on the pressure side 320 of the blade 30 is greater, and there will be a certain pressure difference between the suction side 310 and the pressure side 320, so that the blade 30 obtains lift.

[0060] The air bag 110 is arranged at least on the suction side 310 of the blade 30, which can block the airflow on the suction side 310 of the blade 30, so that the airflow forms a vortex on the suction side 310 of the blade 30, reducing the flow rate of the airflow, thereby increasing the pressure on the suction side 310 of the blade 30, and reducing the pressure difference between the suction side 310 and the pressure side 320 of the blade 30, so that the lift of the blade is reduced, the system damping is increased, and the vibration of the blade 30 is suppressed.

[0061] Furthermore, the air bag 110 also extends from the suction side 310 of the blade 30 to the pressure side 320 of the blade 30 , so that the flow velocity of the airflow flowing through the pressure side 320 of the blade 30 is reduced and the pressure difference between the pressure side 320 and the suction side 310 is reduced.

[0062] In these embodiments, the air bag 110 is arranged on the suction side 310 of the blade 30 and the pressure side 320 of the blade 30, which can block the airflow on the suction side 310 and the pressure side 320 of the blade 30, so that the airflow can form vortices on the suction side 310 and the pressure side 320 of the blade 30, thereby reducing the flow rate of the airflow, thereby balancing the pressure on the suction side 310 and the pressure side 320 of the blade 30, reducing the pressure difference between the suction side 310 and the pressure side 320 of the blade 30, and achieving the purpose of suppressing the vibration of the blade 30.

[0063] According to the Bernoulli equation, the greater the gas flow rate, the smaller the pressure. The air flow speed on the pressure side 320 of the blade 30 surface is slow and the pressure is high, while the pressure on the suction side 310 is low, which will generate a pressure from the pressure side toward the suction side, causing the blade 30 to swing in one direction; and when the wind conditions change, there is a probability that the pressure on both sides will shift. If the wind changes periodically, it will cause the blade 30 to swing frequently and produce vortex-induced vibration. By reducing the airflow velocity flowing through the surface of the blade 30, the pressure difference on both sides of the blade 30 can be reduced, thereby reducing vortex-induced vibration and suppressing the vibration of the blade 30.

[0064] Moreover, after the sheet area 10 is blown up by the wind, a negative pressure area will be formed on the side of the sheet area 10 close to the blade 30, and a pressure difference will be formed on both sides of the sheet area 10. This pressure difference will act on the blade 30 through the strip area 20 to pull the blade 30. Once the blade 30 vibrates toward the suction side 310 or the pressure side 320, it can suppress the vibration of the blade 30 and improve the vibration suppression effect.

[0065] In a specific application, the sheet area 10 made of flexible material can be surrounded on the surface of the blade 30 to form a scooter bag 110 with an air inlet. When there is no airflow to support the scooter bag 110, that is, when there is no wind or little wind, the scooter bag 110 naturally sags and is in a relaxed state. The scooter bag 110 located above the blade 30 is attached to the surface of the blade 30, and the scooter bag 110 located below the blade 30 is used by gravity and sags below the blade 30 (refer to Figure 3 In the case of strong winds, the airflow can open the air bag 110 through the air inlet, so that the air bag 110 is blown into a curved shape similar to a hemisphere (reference Figure 3 It should be noted that the air bag 110a and the air bag 110b are actually one air bag 110, which is mainly marked to distinguish different states of the air bag 110, and does not include both the air bag 110a and the air bag 110b.

[0066] Furthermore, in some embodiments, the air bag 110 has a hollow through hole (not shown in the figure) to reduce the wind resistance of a single air bag 110. The hollow through hole is easy to process, and can be directly punched on the air bag 110. The wind resistance of the air bag 110 can be reduced through a simple process, and the problems such as the strip area 20 being torn due to excessive resistance of the air bag 110 can be prevented, and the pressure of the strip area 20 on the local surface of the blade 30 can be prevented from being too large, causing damage to the surface of the blade 30.

[0067] Furthermore, in some embodiments, the length of the strip region 20 may vary within a range of 0 to 90% of the local circumference to obtain blade vibration suppression devices with different damping.

[0068] Furthermore, in some embodiments, the blade vibration suppression device further includes a support member (not shown in the figures), and the support member is used to prop up the sheet region 10 .

[0069] As an example, the support member may be a plastic stick that can be elastically deformed, etc., to support the air bag 110. Since the air bag 110 itself has a certain weight, it may not be able to be opened when the wind force is small, and it is difficult to play a vibration suppression role. Therefore, by providing a support member, the air bag 110 is kept in a certain open state, so that the air bag 110 can be inflated even when the wind force is small, and the vibration of the blade 30 can also be suppressed.

[0070] As an example, optionally, the support member can be in an arc shape, so as to expand the air bag 110 into a hemispherical shape; further, the support member can be a foldable support member, and when not needed, the support member is folded and the air bag 110 is not propped up, thereby saving space and facilitating transportation, etc.; when it is needed, the support member is propped up so that the support member props up the air bag 110 into a hemispherical shape, thereby suppressing the vibration of the blades 30.

[0071] Further, in some embodiments, the flexible material is any one or more combinations of fabric or plastic cloth.

[0072] In these embodiments, the blade vibration suppression device is made of a flexible material, and the flexible material is any one or more combinations of fabrics or plastic cloths. The fabrics may include relatively strong fabrics such as canvas, polyester cloth, nylon cloth, and Oxford cloth. The above-mentioned flexible materials have the advantages of low cost, strength, light weight, easy storage, low transportation cost, etc., and can be recycled and reused.

[0073] In specific applications, the material of the vibration suppression device can be cotton, linen, chemical fiber and other soft materials made by various weaving or non-woven, pultrusion and other processes.

[0074] A second aspect of the present disclosure provides a blade assembly, which includes a blade 30 and a blade vibration suppression device as described in any one of the above embodiments, wherein the blade vibration suppression device is sleeved on the tip region of the blade 30 .

[0075] The blade assembly provided in the embodiment of this aspect has the blade vibration suppression device of any of the above embodiments, and thus has the beneficial effects of any of the above embodiments, which will not be described in detail here.

[0076] Furthermore, in some embodiments, the blade vibration suppression device is disposed within a range of 50% to 100% of the span length of the blade 30 starting from the blade root, and can play a suppressing role to varying degrees.

[0077] As an example, the blade vibration suppression device is sleeved within the range of 85%-99% of the span length of the blade 30. The installation range of the blade vibration suppression device is within the range of 85% to 95% of the span length from the blade root to the blade 30. On the one hand, based on the characteristic that wind resistance is positively correlated with wind speed, the blade vibration suppression device is installed in the range close to the blade tip, and the high damping resistance device in the range close to the blade tip can be used to solve the yard vibration problem caused by strong wind in the wind direction from the leading edge to the trailing edge and from the trailing edge to the leading edge; in addition, the installation range is within the range of 85% to 95% of the span length from the blade root to the blade 30, which can also avoid interference with aerodynamic accessories installed on the blade 30, such as vortex generators.

[0078] The following describes the dynamic working process of a blade vibration suppression device according to a specific embodiment of the present application in conjunction with the accompanying drawings. Figure 3 In the middle wind bag 110b, when there is no wind or little wind, the sheet area 10 of the flexible material naturally droops, with the upper section attached to the upper surface of the leaf and the lower section as a whole drooping below the lower surface of the blade 30 due to gravity.

[0079] Taking the air inlet of the airbag 110 facing the leading edge side 340 of the blade 30 as an example, when a certain wind speed is reached, such as 8m / s or more, and the wind direction is from the leading edge to the trailing edge or at a certain angle, such as less than 45°, at this time, due to the pressure difference resistance, the sheet area 10 (such as a canvas bag) will be blown into a curved shape similar to a hemisphere, and the airbag 110 is opened, see here Figure 3 The wind passing through the blade 30 forms a turbulent vortex due to separation, causing the upper and lower sides of the blade 30 to vibrate. When the wind direction forms a certain angle with the chord direction of the blade 30, the wind resistance exerts a lateral force on the sheet area 10, that is, a spanwise force component. Figure 3 The strip region 20 in the blade vibration suppression device will provide a constraint to prevent the blade vibration suppression device from moving in the span direction. Figure 2 As shown in 110a.

[0080] When the wind direction is from the trailing edge to the leading edge, or at a certain angle, such as less than 45°, and the wind direction is along the span direction of the blade 30, the shape of the canvas is slightly affected at low wind speeds. When the wind speed is high, such as greater than 10m / s, the canvas is affected by the wind and is pressed tightly against the surface of the blade 30.

[0081] It is understandable that the embodiment in which the air inlet of the air bag 110 faces the trailing edge side 330 of the blade 30 is similar to the above-mentioned embodiment in which the air inlet of the air bag 110 faces the leading edge side 340 of the blade 30, and will not be described in detail here.

[0082] like Figure 4 As shown, in a specific embodiment of the present invention, a 95m blade using the blade vibration suppression device of the present invention is placed in a storage yard as a test object, and a test verification is carried out for more than 300 hours. The verification period includes winds of more than 18m / s, and the wind directions include the front edge to the rear edge and at a certain angle, and the rear edge to the front edge and at a certain angle. Figure 4 As shown, Figure 4 The top diagram is the original data collected by the acceleration sensor, and the vibration diagram below is the vibration result after the original collected data is reset to zero. According to the diagram, it can be clearly concluded that the maximum acceleration during the verification period is about 0.1g (g is the acceleration of gravity), which is less than the threshold value (0.15-0.2g). No obvious vibration occurred during the verification period of the unit in this embodiment.

[0083] In order to better understand the present invention, the principle of stall-induced flutter and the mechanism by which the vibration suppression device of the present invention can suppress vibration are briefly analyzed below.

[0084] Figure 5 It is a stall-induced flutter model with a single fixed vibration direction. In this simplified model, the airfoil vibrates in a single degree of freedom along the direction perpendicular to the incoming flow.

[0085] According to the simplified single-degree-of-freedom model, vibration causes periodic changes in the angle of attack, which in turn causes periodic changes in the aerodynamic force. When the direction of the increase in aerodynamic force is the same as the direction of vibration, or in other words, there is a phase difference between the aerodynamic force and the vibration displacement within a vibration cycle, the aerodynamic force does positive work within a vibration cycle, resulting in the accumulation of total system energy. The mechanical energy of the incoming flow is converted into the elastic potential energy of the bending deformation of the blade, resulting in a tendency for the blade deformation to increase, which ultimately manifests as self-excited vibration with a continuous increase in the blade deflection. For example, at a large angle of attack, the blade vibrates upward, and the angle of attack α0 reduces the lift coefficient C. L Increase, C L If the vibration direction component increases and its direction is the same as the vibration direction, the vibration will tend to increase.

[0086] According to the technical solution of the present invention, by providing a vibration suppression device, the pressure difference between the pressure side and the suction side of the blade can be reduced, thereby reducing the lift and further reducing the energy causing the excitation of the blade flutter.

[0087] By generalizing the previous single-degree-of-freedom simplified model, the stall-induced flutter model of the airfoil in any vibration direction x can be obtained. Figure 6 The stall-induced flutter model of the airfoil in any vibration direction is shown. Since the aerodynamic forces in other directions do not work on the vibration, only the aerodynamic force of the blade airfoil in the vibration direction is discussed below. The aerodynamic force F in the vibration direction x is x And F0 can be expressed by the following equations (2) and (3) respectively:

[0088]

[0089]

[0090] in,

[0091]

[0092] Based on equations (2) and (3), the aerodynamic force F under dynamic conditions is x The aerodynamic resultant force F0 in the steady state is linearized at the equilibrium point x=0, that is, a first-order Taylor expansion is performed according to the following formula (4) to obtain the equivalent damping coefficient η of the model, which can be expressed by the following formula (5).

[0093] F x ≈F0-ηx Formula (4)

[0094]

[0095] Among them, in the above formula (2), formula (3), formula (4), formula (5), the meaning of each parameter is as follows:

[0096] η represents the equivalent damping coefficient;

[0097] F x Aerodynamic resultant force in unsteady state;

[0098] The aerodynamic resultant force in the F0 steady state;

[0099] x vibration direction;

[0100] ρ air density;

[0101] c chord length;

[0102] W is the incoming flow velocity under non-steady state;

[0103] W0 Incoming flow velocity in steady state;

[0104] C L lift coefficient;

[0105] C D Drag coefficient;

[0106] α is the angle of attack in the unsteady state;

[0107] α0 angle of attack in steady state;

[0108] φ is the inflow angle in the unsteady state;

[0109] φ0 is the inflow angle in steady state;

[0110] θ is the angle between the vibration direction and the reference line;

[0111] C′ L The gradient of the lift coefficient with respect to the angle of attack;

[0112] C′ D The gradient of the drag coefficient with respect to the angle of attack.

[0113] It can be seen from formula (5) that, in addition to the vibration direction, other parameters that affect the vibration include parameters such as the angle of attack, the incoming flow velocity, the lift and drag coefficient and its gradient. When η is negative, the aerodynamic resultant force at the cross section of the blade 30 does positive work, resulting in instability. It can be seen from the expression (5) of η that the way to increase damping and improve stability can be to increase the drag coefficient, reduce the lift coefficient, and reduce the gradient of the lift and drag coefficients. In the present invention, by installing a vibration suppression device on the blade 30, it is possible to increase the drag coefficient, reduce the lift coefficient, and reduce the lift and reduce the gradient of the drag coefficient at the same time, thereby achieving the purpose of increasing damping and improving blade stability.

[0114] In formula (5), C D The coefficient range of the term is larger than that of the other two terms. D The most efficient way to increase the damping coefficient is D When η is large and changes little with the angle of attack, it can ensure that η is always greater than zero at any large wind speed.

[0115] The expression of formula (5) can also be used to analyze Figure 5 The stall-induced flutter model with a single fixed vibration direction is shown in FIG. In this model, since the vibration direction of the blade section is perpendicular to the incoming flow direction, θ-φ0=π / 2. Substituting into equation (5), the part in the brackets of equation (5) can be simplified to 2(C D +C′ L ), it can be seen that when C′ L Negative and its absolute value is greater than C D When , the system is unstable. In this case, C DThe coefficient of the term ranges from [2,4], which is larger than the coefficients of the other two terms, indicating that the C D The most efficient way to increase the damping coefficient is D It is larger than the coefficients of the other two terms, so it can ensure that η is always greater than zero, thereby ensuring the stability of the system.

[0116] According to the embodiment of the present disclosure, a vibration suppression device is provided so that negative pressure is formed on the leeward side of the vibration suppression device. Due to the pressure difference on both sides, the blade is subjected to an opposite pressure difference resistance in the vibration direction, thereby achieving the purpose of increasing C D The purpose is to more effectively increase the equivalent damping coefficient η and enhance the vibration suppression effect of the blade.

[0117] Figure 7 and Figure 8 The velocity field result of the two-dimensional CFD (Computational Fluid Dynamics) simulation of the present invention is shown in the figure. The existence of the vibration suppression device intensifies the surface flow separation between the pressure surface and the suction surface of the blade 30, making the surface velocities on both sides of the blade 30 tend to be consistent, thereby causing the pressure difference to decrease and the lift to decrease. According to formula (5), it can be determined that the damping coefficient can be increased, thereby enhancing the vibration suppression effect; at the same time, due to the obstruction of the blade vibration suppression device, the airflow velocity of the blade vibration suppression device on the side close to the blade 30 decreases and approaches 0, thereby forming a negative pressure on the other side, generating a large pressure difference resistance, and because the flow velocity on the side of the device close to the blade 30 at different attack angles is close to 0 and relatively stable, it shows a small resistance gradient. According to formula (5), it can be determined that the damping coefficient can be increased and the vibration suppression effect can be enhanced. The present invention has the most significant effect on increasing the drag coefficient by adopting the vibration suppression device. At a large angle of attack, the drag coefficient can be increased from 0.3-0.5 to 1.5-2.0.

[0118] It is worth noting that in an actual three-dimensional scene, the equivalent stiffness distribution of the blade 30 is inversely proportional to the cube of the length from the blade root, so the most efficient way is to set the blade vibration suppression device at the blade tip; the blade tip resistance part makes the direction of increase of the aerodynamic force opposite to the direction of speed, and the aerodynamic force does negative work, avoiding the increase and accumulation of total energy in the system, thereby achieving the effect of the damper.

[0119] Fig. 9 and Fig.10 Based on the on-site parameters (wind speed, air density, etc.) of the disclosed embodiment, the corresponding aerodynamic data (C L ,C D ,C′ L ,C′ D ), the calculation results obtained by applying the above model. Among them, Figure 7The figure shows the calculation results when the vibration suppression device disclosed in the present invention is not installed, and the calculation uses basic aerodynamic data; Figure 8 The result after installing the vibration suppression device disclosed in the present invention is shown, and the modified aerodynamic data is used for calculation (relative to the basic aerodynamic data, the main difference is that the lift coefficient is reduced and the drag coefficient is increased). In the application scenario of this example, the blade vibration direction occurs near the chord direction, corresponding to the dotted box area in the figure. By observing the dotted box areas in the two figures, it can be seen that the damping coefficient is significantly improved after installing the vibration suppression device, and is greater than 0 at all angles of attack.

[0120] According to the vibration suppression device of the present invention, the damping is increased by changing the flow on the blade surface and by increasing the drag coefficient. Therefore, even under high wind speeds (for example, wind speeds greater than 20 m / s), vibration suppression by adding resistance can be achieved, thereby ensuring the vibration suppression effect and the structural strength of the device and solving the stability problems in blade yards and blade shutdown maintenance conditions.

[0121] Although the embodiments of the present application have been described in detail above, those skilled in the art may make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. It should be understood that, in the view of those skilled in the art, these modifications and variations will still fall within the spirit and scope of the embodiments of the present disclosure defined by the claims.

Claims

1. A blade vibration suppression device, used for installation on a blade (30) of a wind turbine generator set, characterized in that: The blade vibration damping device is made of a flexible material, and comprises a sheet-like region (10) and a strip-like region (20) integrally connected to the sheet-like region (10); the strip-like region (20) and the sheet-like region (10) are enclosed to form a ring, so that they can be sleeved on the blade (30); the sheet-like region (10) can enclose a wind bag (110) on one side of the blade (30); under the action of external wind, the wind bag (110) can be opened, so that the damping of the blade (30) is increased.

2. The blade vibration suppression device according to claim 1, characterized in that: The sheet-like region (10) and the corresponding belt-like region (20) are made of the same piece of flexible material, or the sheet-like region (10) and the corresponding belt-like region (20) are sewn together.

3. The blade vibration suppression device according to claim 1, characterized in that: The blade vibration suppression device comprises a plurality of the sheet-shaped regions (10) and corresponding strip-shaped regions (20), and a plurality of the wind-absorbing bags (110) can be arranged in sequence along the span direction of the blade (30).

4. The blade vibration suppression device according to claim 3, characterized in that: The plurality of ventilation bags (110) are made from the same piece of flexible material, or the plurality of ventilation bags (110) are sewn together.

5. The blade vibration suppression device according to claim 4, characterized in that: The strip-shaped region (20) has a connecting belt (210), the two ends of the plurality of the ventilation bags (110) are each connected to one of the connecting belts (210), and two adjacent ventilation bags (110) are connected to the same connecting belt (210); Wherein, at least the connecting belts (210) located at the two ends of the blade (30) in the span direction are connected to the blade (30) to limit the movement of the blade vibration suppression device along the span direction of the blade (30).

6. The blade vibration suppression device according to claim 3, characterized in that: Each of the sheet-shaped regions (10) has a plurality of connecting bands (210) in the band-shaped region (20) corresponding to the sheet-shaped region (10).

7. The blade vibration suppression device according to claim 1, characterized in that: The band-shaped area (20) and the sheet-shaped area (10) are enclosed to form a ring with a certain tension force, which can be tightly sleeved on the blade (30) and make the wind bag (110) in a relaxed state in a natural state; or The strip-shaped area (20) is fixed to the blade (30) by means of a binding belt, and the wind bag (110) is in a relaxed state in a natural state.

8. The blade vibration suppression device according to claim 3, characterized in that: The openings of the plurality of air bags (110) are oriented toward the leading edge side (340) and / or the trailing edge side (330) of the blade (30).

9. The blade vibration suppression device according to claim 8, characterized in that: In the span direction of the blade (30), a plurality of sheet-like regions (10) are arranged continuously, or each sheet-like region (10) and a strip-like region (20) are arranged alternately.

10. The blade vibration suppression device according to claim 1, characterized in that: At least a portion of the air bag (110) is located on the suction side (310) of the blade (30) so as to reduce the flow rate of the airflow passing through the suction side (310) of the blade (30).

11. The blade vibration suppression device according to claim 10, characterized in that: The air bag (110) also extends from the suction side (310) of the blade (30) to the pressure side (320) of the blade (30), so that the flow rate of the airflow flowing through the pressure side (320) of the blade (30) is reduced, and the pressure difference between the pressure side (320) and the suction side (310) is reduced.

12. The blade vibration suppression device according to claim 1, characterized in that: The blade vibration suppression device also includes a support member, and the support member is used to prop up the sheet-shaped area (10).

13. A blade assembly, characterized in that: The blade assembly comprises a blade (30) and a blade vibration suppression device according to any one of claims 1 to 12, wherein the blade vibration suppression device is sleeved on a blade tip region of the blade (30).

14. The blade assembly according to claim 13, characterized in that The blade vibration suppression device is sleeved within a range of 85%-99% of the span length of the blade (30).

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