Blade vibration suppression device, blade assembly and wind turbine generator set

Abstract

The disclosed embodiment provides a blade vibration suppression device, a blade assembly and a wind turbine generator set. The blade vibration suppression device includes a wind blocker and a connecting member. The connecting member is used to connect the wind blocker to the blade of the wind turbine generator set. One side of the wind blocker is formed into a wind-catching concave surface. When the wind-catching concave surface is the windward surface, the damping of the blade can be increased, thereby suppressing the vibration of the blade. The blade vibration suppression device provided by the embodiment of this aspect is based on the characteristic that wind resistance is positively correlated with wind speed. The wind blocker is arranged on the blade, so that the damping of the blade is increased under the action of the wind blocker, thereby solving the problem of blade 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, a blade assembly and a wind power generator set. 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. Usually, the mesh needs to be installed in a large range of blades. Especially at high wind speeds, the vibration suppression effect cannot be guaranteed. In practical applications, it is usually necessary to cooperate with the anchor fixation method. Second, the cost is high, it is difficult to recycle and reuse, and it is not convenient to transport. The mesh itself has the characteristics of customization and large material consumption, resulting in high cost. At the same time, since the mesh cannot be shared between different blade models, it is difficult to reuse the mesh, which further exacerbates the cost problem. In addition, the mesh itself is large in size and inconvenient to transport, resulting in high transportation costs. Third, the mesh interferes with pneumatic accessories. At present, 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 root of the blade to the extension of the blade, which is also the installation range of the mesh. Therefore, it will interfere with the mesh, causing damage to the VG and difficulty in disassembling and installing the mesh. Summary of the invention

[0004] The present disclosure aims to at least solve the problems in the above-mentioned prior art or related technology that blade vibration can easily cause damage to the blade shape and structure or even scrap it, and the existing solution of suppressing vibration by installing a mesh sleeve on the blade has the disadvantages of insufficient reliability, high cost, non-reusability, interference between the mesh sleeve and pneumatic accessories, etc.

[0005] To achieve the above-mentioned purpose, a first aspect embodiment of the present disclosure provides a blade vibration suppression device, which includes a wind blocking member and a connecting member. The connecting member is used to connect the wind blocking member to the blade of a wind turbine. One side of the wind blocking member is formed as a wind-absorbing concave surface, which can increase the damping of the blade when the wind-absorbing concave surface is the windward surface, thereby suppressing the vibration of the blade.

[0006] In some embodiments, the connecting member connects the wind blocking member to the blade, so that a gap exists between the wind blocking member and the outer surface of the blade in a working state, thereby increasing the damping of the blade without changing the aerodynamic shape of the blade.

[0007] In some embodiments, the connecting member can connect the wind blocking member to the blade and locate the wind-catching concave surface on the suction side of the blade, so as to reduce the velocity of the airflow flowing through the suction side of the blade, thereby reducing the lift of the blade and increasing the damping.

[0008] In some embodiments, the wind-driving concave surface also extends from the suction side of the blade to the pressure side of the blade, so that the flow velocity of the airflow flowing through the pressure side of the blade is reduced and the pressure difference between the pressure side and the suction side is reduced, thereby reducing the lift of the blade and increasing the damping.

[0009] In some embodiments, after the external airflow flows through the blade, it enters the wind-driving concave surface, so that a negative pressure area is formed on the side of the wind-driving concave surface facing away from the blade, thereby applying a pressure difference resistance to the vibration of the blade, so that the resistance coefficient of the blade increases.

[0010] In some embodiments, there are multiple wind blocking members, which can be arranged at intervals along the span direction of the blade.

[0011] In some embodiments, a plurality of ventilation holes are provided on the wind blocking member to reduce the wind resistance of the wind blocking member.

[0012] In some embodiments, the wind blocking member is made of a flexible material.

[0013] In some embodiments, the wind blocking member is a flexible sheet, and the connecting member is a tying rope, which is fixedly connected to the flexible sheet, and can fix the flexible sheet on the blade, and make the flexible sheet form a bag shape with an air inlet opening on the surface of the blade, and the flexible sheet can be expanded under the action of external airflow.

[0014] In some embodiments, the binding ropes include cross binding ropes and annular binding ropes, the flexible sheet is roughly square, and its two ends are respectively wrapped around the pressure side and the suction side of the blade, and two corners of the flexible sheet are located on the pressure side of the blade, and the other two corners are located on the suction side of the blade. On each of the pressure side and the suction side, the cross binding ropes bring the two corners of the flexible sheet close to each other, thereby forming an air inlet opening between the two corners of the flexible sheet. The annular binding ropes are connected to the two side edges of the middle part of the flexible sheet, and are wrapped around the circumference of the blade to prevent the flexible sheet from moving in the span direction of the blade.

[0015] In some embodiments, the blade vibration suppression device further includes a bracket, which is located inside the wind-absorbing concave surface of the wind-blocking member and is used to prop open the wind-blocking member made of a flexible material.

[0016] A second aspect of the present disclosure provides a blade assembly, including a blade. The blade assembly also includes a blade vibration suppression device as described in any one of the above embodiments, and the blade vibration suppression device is installed on the leading edge side and / or the trailing edge side of the blade.

[0017] 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.

[0018] In some embodiments, the blade assembly further comprises a blade vibration suppression device according to any one of claims 1 to 11, and the blade vibration suppression device is installed on the leading edge side and / or the trailing edge side of the blade.

[0019] In some embodiments, the blade vibration suppression device is installed in the range of 85% to 95% in the span direction of the blade.

[0020] In some embodiments, the blade vibration suppression device is installed at one end close to the blade tip, and the distance between the wind blocking member and the blade tip is greater than or equal to 2 m and less than or equal to 10 m.

[0021] In some embodiments, the choke can cover 50% to 80% of the chord-wise width of the blade.

[0022] In some embodiments, there are multiple blade vibration suppression devices, which are arranged at intervals along the span direction of the blade, and the distance between two adjacent blade vibration suppression devices is 20 cm-50 cm.

[0023] In some embodiments, the width of each wind blocking member in the span direction of the blade is 1 m-4 m.

[0024] In some embodiments, the laying width of the blade vibration suppression device in the span direction of the blade is 8m to 10m.

[0025] The blade vibration suppression device provided in the embodiment of this aspect is based on the characteristic that wind resistance is positively correlated with wind speed. A wind-blocking member is arranged on the blade, so that the drag coefficient of the blade increases under the action of the wind-blocking member, thereby solving the problem of yard vibration caused by strong winds. At the same time, the strength of each component is taken into consideration to ensure that each component does not fail under strong wind conditions. The wind-blocking member used in the blade vibration suppression device provided in the embodiment of this aspect is small in size, easy to transport, and has the characteristics of low cost and reusability. The application scenarios of the present invention include but are not limited to the storage of blades in the yard, the maintenance of blades after hoisting and before grid connection, and the shutdown maintenance during blade operation.

[0026] 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 apparent from the description or may be learned through practice of the present general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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:

[0028] Figure 1 is a schematic diagram of a single blade vibration suppression device installed on the trailing edge side of a blade according to an embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of a blade vibration suppression device according to an embodiment of the present invention after being blown up;

[0030] Figure 3 is a schematic diagram of the installation positions of multiple blade vibration suppression devices on the trailing edge side of a blade according to an embodiment of the present invention;

[0031] Figure 4 is a schematic diagram of a single blade vibration suppression device installed on the leading edge side of a blade according to an embodiment of the present invention;

[0032] Figure 5 is a schematic diagram of a plurality of blade vibration suppression devices installed on the leading edge side of a blade according to an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of two blade vibration suppression devices respectively installed on the leading edge side and the trailing edge side of the blade according to one embodiment of the present invention;

[0034] Figure 7 is a schematic diagram of a plurality of blade vibration suppression devices respectively installed on the leading edge side and the trailing edge side of the blade according to one embodiment of the present invention;

[0035] Figure 8 is a schematic diagram of two blade vibration suppression devices being relatively installed on the leading edge side and the trailing edge side of a blade according to an embodiment of the present invention;

[0036] Fig. 9 is a schematic diagram of a plurality of blade vibration suppression devices according to an embodiment of the present invention being relatively installed on the leading edge side and the trailing edge side of the blade respectively;

[0037] Fig.10 is a schematic diagram of a blade vibration suppression device with ventilation holes according to an embodiment of the present invention;

[0038] Fig.11 An example is shown in which the wind blocking member is a one-piece structure.

[0039] Fig.12 It is a schematic diagram of the verification result of the vibration suppression effect of the blade vibration suppression device on the blade according to an embodiment of the present invention.

[0040] Fig.13is a single vibration direction stall-induced flutter model according to an embodiment of the present invention;

[0041] Fig.14 is an arbitrary vibration direction stall-induced flutter model according to an embodiment of the present invention;

[0042] Fig.15 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;

[0043] Fig.16 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;

[0044] Fig.17 and Fig.18 Schematic diagrams showing the results of calculating the damping coefficient of a blade without the vibration suppression device of the present invention and a blade with the vibration suppression device of the present invention using field parameters are shown respectively.

[0045] Figures 1 to 18 Description of reference numerals:

[0046] 10 wind blocks, 110 wind concave surfaces, 120 ventilation holes,

[0047] 20 connectors, 210 cross tying ropes, 220 ring tying ropes,

[0048] 30 blades, 310 suction side, 320 pressure side, 330 trailing edge side, 340 leading edge side. DETAILED DESCRIPTION

[0049] 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.

[0050] 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.

[0051] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] The definitions of directional terms such as "upper", "lower", "top" and "bottom" in the present disclosure are all based on the directional definitions when the product is in normal use and placed upright.

[0056] Unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meanings as those generally understood by those skilled in the art to which the present disclosure belongs after understanding the present disclosure. Unless explicitly defined as such herein, terms such as those defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0057] Furthermore, in the description of examples, when it is considered that a detailed description of a well-known related structure or function would cause vague interpretation of the present disclosure, such a detailed description will be omitted.

[0058] The following will be combined Figures 1 to 15 A blade vibration suppression device and a blade assembly provided in an embodiment of the present disclosure are introduced.

[0059] like Figures 1 to 9 As shown, a first aspect embodiment of the present disclosure provides a blade vibration suppression device, which includes a wind blocker 10 and a connecting member 20. The connecting member 20 is used to connect the wind blocker 10 to the blade 30 of the wind power generation group. One side of the wind blocker 10 is concave to form a wind-sharing concave surface 110, thereby forming a wind-sharing cavity. When the wind-sharing concave surface 110 is the windward surface, the damping of the blade 30 can be increased, thereby suppressing the vibration of the blade 30.

[0060] The blade vibration suppression device provided in the embodiment of this aspect is based on the characteristic that wind resistance is positively correlated with wind speed. A wind blocking member 10 is provided on the blade 30, so that the damping of the blade 30 is increased under the action of the wind blocking member 10, thereby solving the problem of yard vibration caused by strong winds. At the same time, the strength of each component is considered to ensure that each component does not fail under strong wind conditions. The wind blocking member 10 used in the blade vibration suppression device provided in the embodiment of this aspect is small in size, easy to store and transport, and has the characteristics of low cost and reusability. 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 being connected to the grid, and the shutdown maintenance conditions during the operation of the blades 30.

[0061] In some embodiments, Figures 1 to 9 As shown, the connecting member 20 connects the choke 10 to the blade 30 , so that a gap exists between the choke 10 and the outer surface of the blade 30 in the working state, thereby increasing the damping of the blade 30 without changing the aerodynamic shape and aerodynamic performance of the blade 30 .

[0062] In these embodiments, the wind blocking member 10 is connected to the blade 30 through the connecting member 20, so that the wind blocking member 10 and the outer surface of the blade 30 are relatively independent, and do not need to match the outer contour of the blade like a net bag, so it can be applied to blades of different airfoils and has good versatility. In addition, when the blade vibration suppression device is not needed, the wind blocking member 10 can be separated from the blade 30 by loosening the connecting member 20, which is convenient for disassembly and can be reused.

[0063] In addition, the method of connecting the wind-blocking member 10 to the blade through the connecting member 20 does not need to be put on the blade like a net bag. Therefore, it can avoid interference with pneumatic accessories on the blade, and solves the problem of interference with pneumatic accessories such as VG (Vortex Generator), causing damage to the VG and difficulty in installing and removing the net.

[0064] In some embodiments, Figures 1 to 9As shown, the connecting member 20 can connect the wind blocking member 10 to the blade 30 and make the wind-absorbing concave surface 110 at least 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 .

[0065] Normally, when the air flow flows through the periphery of the blade, the air flow velocity on the suction side 310 of the blade 30 is greater than the air flow velocity on the pressure side 320 of the blade 30. According to the Bernoulli equation, the greater the gas flow velocity, 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 obtains lift.

[0066] The ventilation concave surface 110 is set 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.

[0067] Furthermore, in some embodiments, Figures 1 to 9 As shown, the wind-driving concave surface 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, so that the lift of the blade airfoil is reduced and the system damping is increased.

[0068] In these embodiments, the wind-driving concave surface 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.

[0069] 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.

[0070] In some embodiments, after the external airflow flows through the blade 30 and enters the wind-absorbing concave surface 110, a negative pressure area is formed on the side of the wind-absorbing concave surface 110 away from the blade 30. The negative pressure area formed on the side of the wind-absorbing concave surface 110 away from the blade 30 is conducive to supporting the wind-blocking member 10 made of flexible material, so that the wind-blocking member 10 is blown into a hemispherical curved surface shape, and on the other hand, a pressure difference is formed on both sides of the wind-blocking member 10, so that the wind-blocking member 10 can apply a pressure difference resistance roughly consistent with the vibration direction of the blade to the blade 30, thereby suppressing the vibration of the blade.

[0071] According to some embodiments, a single air blocker 10 may be provided, and the length of the air blocker 10 in the span direction of the blade may be set according to the actual vibration suppression requirements. As an example, in the case of providing a single air blocker 10, the length of the air blocker 10 may be relatively large. In this case, multiple sets of connecting members 20 may be used to fix the air blocker 10 on the blade 30 in the span direction of the blade to ensure the connection strength between the air blocker 10 and the blade. In this case, a single air blocker 10 may form multiple air inlets. Fig.11 An example is shown in which the wind blocking member 10 is a one-piece structure.

[0072] In some embodiments, Figure 2 , Figure 3 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, the wind blocking member 10 can be provided in plurality and can be arranged at intervals along the span direction of the blade 30. Such an arrangement can not only reduce the length of each wind blocking member 10, avoid the length of a single wind blocking member 10 being too long and increasing the difficulty of installation, but also ensure the vibration suppression effect of the blade 30.

[0073] Furthermore, in some embodiments, Fig.10 As shown, the wind blocking member 10 may be provided with a plurality of ventilation holes 120 for reducing the wind resistance of a single wind blocking member 10. The ventilation holes 120 are easy to process and can be directly punched on the wind blocking member 10. The wind resistance of the wind blocking member 10 can be reduced through a simple process, and the wind resistance of the wind blocking member 10 can be prevented from being broken due to excessive resistance of the wind blocking member 10, and the pressure of the connecting member 20 on the local surface of the blade can be prevented from being too high, causing damage to the blade surface.

[0074] In some embodiments, the wind blocking member 10 is made of a flexible material. As an example, optionally, the flexible material is a combination of any one or more of fabrics or plastic cloth. Among them, the fabric may include relatively strong fabrics such as canvas, polyester cloth, nylon cloth, and Oxford cloth. The above-mentioned flexible material has the advantages of low cost, strength, light weight, easy storage, low transportation cost, etc., and can be recycled and reused; in addition, when there is no need to set up a blade vibration suppression device, the blade vibration suppression device can be detached from the blade 30 by disconnecting the connecting piece 20, which is convenient for disassembly, and due to the light weight of the above-mentioned flexible material, the blade vibration suppression device can fall freely without injuring the staff.

[0075] In other embodiments, the wind blocker 10 can be made of a hard material. Compared with the wind blocker 10 made of a flexible material, there is no need to blow up the wind blocker 10. One side of the wind blocker 10 made of a hard material can be directly formed into a wind-catching concave surface 110, which increases the drag coefficient of the blade 30, thereby suppressing the vibration of the blade 30, and can also play a good role in light winds. As an example, the wind blocker 10 can be made of a material such as plastic, and one side of the wind blocker 10 is a concave surface. When installed on the blade, the concave side faces the blade.

[0076] In some embodiments, the wind blocking member 10 is a flexible sheet, and the connecting member 20 is a tying rope, which is fixedly connected to the flexible sheet, and can fix the flexible sheet on the blade 30, and make the flexible sheet form a bag with an air inlet opening on the surface of the blade 30, so that the flexible sheet can be expanded under the action of external airflow.

[0077] In these embodiments, a tying rope is selected as the connecting member 20. The tying rope has low cost and can be tied to the surface of the blade 30. The tying rope is fixed to the blade 30 by knotting or hooking other connecting members 20, and the connection between the blade 30 is simple. Figure 1 As shown, the wind blocking member 10 is a flexible sheet, which can be surrounded by a bag with an air inlet opening on the surface of the blade 30. When there is no airflow to support the flexible sheet, that is, when there is no wind or little wind, the flexible sheet naturally droops, and the flexible sheet located above the blade 30 is attached to the surface of the blade 30, and the flexible sheet located below the blade 30 is used by gravity and droops below the blade 30; Figure 2 As shown, in the case of strong winds, the airflow can open the flexible sheet through the air inlet opening, so that the flexible sheet is blown into a hemispherical curved shape.

[0078] In some embodiments, Figure 1As shown, the tying ropes include cross tying ropes 210 and annular tying ropes 220, the flexible sheet is roughly square, and its two ends are respectively wrapped around the pressure side 320 and the suction side 310 of the blade 30, and two corners of the flexible sheet are located on the pressure side 320 of the blade 30, and the other two corners are located on the suction side 310 of the blade 30. The cross tying ropes 210 are used to fix the chord-wise position of the flexible sheet, and are cross-connected with the four corners of the flexible sheet. On the pressure side 320 of the blade 30, the cross-binding ropes 210 are connected to the two corners of the flexible sheet and cross each other, so that the two corners of the flexible sheet are brought close to each other through the cross-binding ropes 210, and then an air inlet opening is formed between the two corners of the flexible sheet, so that wind can enter through the air inlet opening to open the flexible sheet; similarly, on the suction side 310 of the blade 30, the cross-binding ropes 210 are also connected to the two corners of the flexible sheet and cross each other, so that the two corners of the flexible sheet are brought close to each other through the cross-binding ropes 210, and then an air inlet opening is formed between the two corners of the flexible sheet, so that wind can enter through the air inlet opening to open the flexible sheet; the annular binding ropes 220 are connected to the two side edges of the middle part of the flexible sheet, and are wrapped around the circumference of the blade 30 and fixed, so as to fix the spanwise position of the flexible sheet and prevent the flexible sheet from moving in the spanwise direction of the blade 30. As an example, since the annular binding rope 220 is connected to both sides of the flexible sheet, approximately the middle of the left and right sides of the flexible sheet can be fixed on the blade, thereby preventing the flexible sheet from moving in the span direction of the blade.

[0079] As an example, the tying rope may be a binding belt, a binding belt with a tightener, a rope, etc. One cross tying rope 210 may be provided, and two annular tying ropes 220 may be provided.

[0080] In some embodiments, the blade vibration suppression device further includes a bracket (not shown in the figure), which is located inside the wind-shaking concave surface 110 of the wind-blocking member 10, and is used to prop open the wind-blocking member 10 made of a flexible material. As an example, optionally, the bracket may be a plastic stick that can be elastically deformed, etc., to support the wind-blocking member 10. Since the wind-blocking member 10 itself also has a certain weight, it may not be able to be opened when the wind force is small, and therefore, it is difficult to play a vibration suppression role. According to some embodiments of the present application, by providing a bracket, the wind-blocking member 10 is kept in an open state, so that the vibration of the blade can be suppressed even when the wind force is small.

[0081] As an example, optionally, the bracket can be in an arc shape, so as to prop up the wind blocker 10 into a hemispherical shape; further, the bracket can be a foldable bracket, and when the blade vibration suppression device is not needed, the bracket is folded and the wind blocker 10 is not propped up, thereby saving space and facilitating transportation; when the blade vibration suppression device is needed, the bracket is propped up so that the bracket props up the wind blocker 10 into a hemispherical shape, thereby achieving the effect of suppressing blade vibration.

[0082] like Figures 1 to 9 As shown, a second aspect of the present disclosure provides a blade assembly, including 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 installed on the leading edge side 340 and / or the trailing edge side 330 of the blade 30 .

[0083] 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.

[0084] It is worth noting that if Figure 4 and Figure 5 As shown, the blade vibration suppression device can be arranged on the leading edge side 340 of the blade 30, in which case the air inlet opening faces the trailing edge side 330; Figure 1 , Figure 2 and Figure 3 As shown, the blade vibration suppression device can also be arranged on the trailing edge side 330 of the blade 30, in which case the air inlet opening faces the leading edge side 340; of course, as shown in FIG. Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, blade vibration suppression devices may also be provided on both the leading edge side 340 and the trailing edge side 330 of the blade 30 , so that the vibration suppression function can be exerted regardless of the direction from which the external wind blows.

[0085] Furthermore, the blade vibration suppression devices can be grouped according to their orientations. As an example, the blade vibration suppression devices arranged on the leading edge side 340 of the blade 30 are used as the first group of blade vibration suppression devices, and the blade vibration suppression devices arranged on the trailing edge side 330 of the blade 30 are used as the second group of blade vibration suppression devices. The number of the first group of blade vibration suppression devices and the second group of blade vibration suppression devices can be approximately the same, and they are alternately arranged in the span direction of the blade 30; alternatively, the number of the first group of blade vibration suppression devices is less than the number of the second group of blade vibration suppression devices, in which case they may not be arranged in an alternating manner.

[0086] Furthermore, at least a portion of the air inlet openings of the first group of blade vibration suppression devices and at least a portion of the air inlet openings of the second group of blade vibration suppression devices face each other. Specifically, the first group of blade vibration suppression devices and the second group of blade vibration suppression devices can be arranged overlappingly in the span direction of the blade 30, and the air inlet openings of the first group of blade vibration suppression devices and the air inlet openings of the second group of blade vibration suppression devices face each other; the first group of blade vibration suppression devices and the second group of blade vibration suppression devices can also be arranged partially overlappingly in the span direction of the blade 30, that is, a portion of the air inlet openings of the first group of blade vibration suppression devices and a portion of the air inlet openings of the second group of blade vibration suppression devices face each other.

[0087] 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 wind force acting on the wind blocking member 10, the greater the resistance generated, and the greater the increased damping of the blade system. Therefore, by providing the wind blocking member 10, the wind resistance can be efficiently utilized to increase the damping of the blade 30, thereby avoiding stall-induced flutter of the blade 30.

[0088] In some embodiments, the blade vibration suppression device is installed in the range of 85% to 95% in the span direction of the blade 30. That is, the installation range of the blade vibration suppression device is in the range of 85% to 95% 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, which can utilize the characteristics of the high drag coefficient in the range close to the blade tip 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 in the range of 85% to 95% 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.

[0089] In some embodiments, the blade vibration suppression device is installed in the area near the tip of the blade 30, and the distance between the wind blocking member 10 and the blade tip is greater than or equal to 2m and less than or equal to 10m. Within this range, on the one hand, the range within 2m on one side near the tip of the blade 30 can be avoided. Generally speaking, the inner chord length of the blade 30 2m from the tip is too small, which is not convenient for installing the blade vibration suppression device. Therefore, the blade vibration suppression device is installed on the blade 30 outside 2m from the tip and installed inward in sequence; on the other hand, based on the characteristics that wind resistance is positively correlated with wind speed, the blade vibration suppression device is installed within 10m near the tip of the blade, which can utilize the characteristics of the high drag coefficient in the range near the tip of the blade to solve the yard vibration problem caused by strong winds in the wind direction from the leading edge to the trailing edge and from the trailing edge to the leading edge, and at the same time consider the strength of each component to ensure that each component does not fail under strong wind conditions; in addition, the installation range is from 2m to 10m from the tip of the blade, which can also avoid interference with aerodynamic accessories installed on the blade 30, such as vortex generators.

[0090] In some embodiments, Figures 1 to 10 As shown, the wind blocking member 10 can cover at least a portion of the chord width of the blade 30, that is, overlap at least a portion of the blade, for example, covering 50% to 80% of the chord length of the blade 30. Within this range, the wind blocking member 10 covers a sufficient chord width of the blade 30 to solve the vibration problem of the yard 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, and can effectively suppress vibration, while the wind blocking member 10 will not cover too large a chord width of the blade 30 so that it is difficult to be blown up.

[0091] In some embodiments, Figure 2 , Figure 3 , Figure 5 , Figure 7 and Fig. 9 As shown, there are multiple blade vibration suppression devices, which are arranged at intervals along the span direction of the blade 30, and the distance between two adjacent blade vibration suppression devices is 20cm-50cm. This arrangement can avoid mutual interference between two adjacent blade vibration suppression devices, and will not be too far away to affect the vibration suppression effect.

[0092] Figure 1 The schematic diagram of a single blade vibration suppression device installed on the blade 30 is shown. Optionally, in actual application, 3 to 6 blade vibration suppression devices can be used, which are installed in sequence from 2 m away from the blade tip to the blade root, such as Figure 3 , Figure 5 , Figure 7 and Fig. 9 shown.

[0093] In some embodiments, the width of each wind blocking member 10 in the span direction of the blade 30 is 1m-4m. Within this range, it has a sufficient length to effectively suppress vibration, but does not cause excessive resistance due to the excessive width of a single wind blocking member 10 in the span direction of the blade 30, which may easily break the connecting member 20.

[0094] In some embodiments, the blade vibration suppression device is laid with a width of 8m to 10m in the span direction of the blade 30. Within this range, it has a sufficient length to effectively suppress vibration, but does not interfere with other components on the blade 30 due to the excessive width of the blade vibration suppression device in the span direction of the blade 30.

[0095] The dynamic working process of the blade vibration suppression device of the embodiment of the present application is described below in conjunction with the accompanying drawings. Figure 1 As shown, in the case of no wind or light wind, the wind blocking member 10 of the flexible material naturally droops, and the upper section is attached to the upper surface of the blade 30. Due to the fixation of the cross-binding rope 210, an inward closing is formed on the wind blocking member 10, and the lower section of the wind blocking member 10 is used as a whole by gravity and hangs below the lower surface of the blade 30.

[0096] Take the case where the air inlet opening of the wind blocker 10 faces the leading edge 340 of the blade 30 as an example. When a certain wind speed is reached, such as 8m / s or above, and the wind direction is from the leading edge to the trailing edge or at a certain angle, such as less than 45°, the wind blocker 10 (such as a canvas bag) will be blown into a hemispherical curved surface due to the pressure difference resistance. At the same time, the wind passing through the blade 30 will form turbulent vortices due to separation, causing the upper and lower sides of the blade 30 to shake. 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 wind blocker 10, that is, a spanwise force component. At this time, Figure 1 The annular binding rope 220 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 shown.

[0097] 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.

[0098] It is understandable that the embodiment in which the air inlet opening of the air blocking member 10 faces the trailing edge side 330 of the blade 30 is similar to the above-mentioned embodiment in which the air inlet opening of the air blocking member 10 faces the leading edge side 340 of the blade 30, and will not be described in detail here.

[0099] like Fig.12 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 direction includes a certain angle between the leading edge and the trailing edge, and a certain angle between the trailing edge and the leading edge. Fig.11 As shown, Fig.11 The middle figure (a) is the original data collected by the acceleration sensor, and the figure below (b) is the vibration result after the original collected data is reset to zero. According to the figure, 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 of this embodiment.

[0100] 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.

[0101] Fig.13 It is a stall-induced flutter model with a single vibration direction. In this simplified model, the airfoil vibrates in a single degree of freedom along the direction perpendicular to the incoming flow.

[0102] 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.

[0103] 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 that excites the blade flutter.

[0104] 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. Fig.14 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 Fx and F0 in the vibration direction x can be expressed by the following equations (2) and (3), respectively:

[0105]

[0106]

[0107] in,

[0108]

[0109] 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).

[0110] F x ≈F0-ηx Formula (4)

[0111]

[0112] Among them, in the above formula (2), formula (3), formula (4), formula (5), the meaning of each parameter is as follows:

[0113] η-equivalent damping coefficient;

[0114] F x - Aerodynamic resultant force in unsteady state;

[0115] F0-aerodynamic force in steady state;

[0116] x- vibration direction;

[0117] ρ - air density;

[0118] c-chord length;

[0119] W-the combined speed of the downflow wind speed and the vibration wind speed in the unsteady state;

[0120] W0-incoming flow velocity in steady state;

[0121] C L - lift coefficient;

[0122] C D - drag coefficient;

[0123] α-angle of attack in unsteady state;

[0124] α0 - angle of attack in steady state;

[0125] φ - inflow angle in unsteady state;

[0126] φ0-inflow angle in steady state;

[0127] θ-angle between vibration direction and reference line;

[0128] C′ L - the gradient of the lift coefficient with respect to the angle of attack;

[0129] C′ D - Gradient of the drag coefficient with respect to the angle of attack.

[0130] 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.

[0131] 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.

[0132] The expression of formula (5) can also be used to analyze Fig.13 The single vibration direction stall-induced flutter model shown in the figure. Under this model, since the vibration direction of the blade section is perpendicular to the incoming flow direction,

[0133] 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 DWhen , the system is unstable. In this case, C D The 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.

[0134] 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.

[0135] Fig.15 and Fig.16 The velocity field result of the two-dimensional CFD (Computational Fluid Dynamics) simulation of the present invention is shown as follows. The existence of the vibration suppression device aggravates 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. Since 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.

[0136] 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.

[0137] Fig.17 and Fig.18 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, Fig.17 The 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; Fig.18 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.

[0138] 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.

[0139] According to another aspect of the present invention, a wind turbine generator set having the above-mentioned vibration suppression device or blade assembly is also provided.

[0140] 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, characterized in that: The blade vibration suppression device comprises a wind blocking member (10) and a connecting member (20). The connecting member (20) is used to connect the wind blocking member (10) to a blade (30) of a wind power generation group. One side of the wind blocking member (10) is formed as a wind-absorbing concave surface (110). When the wind-absorbing concave surface (110) is a windward surface, the damping of the blade (30) can be increased, thereby suppressing the vibration of the blade (30).

2. The blade vibration suppression device according to claim 1, characterized in that: The connecting member (20) connects the wind blocking member (10) to the blade (30), so that a gap exists between the wind blocking member (10) and the outer surface of the blade (30) in a working state, thereby increasing the damping of the blade (30) without changing the aerodynamic shape of the blade (30).

3. The blade vibration suppression device according to claim 1, characterized in that: The connecting member (20) is capable of connecting the wind blocking member (10) to the blade (30) and positioning the wind-absorbing concave surface (110) on the suction side (310) of the blade (30), so as to reduce the velocity of the airflow flowing through the suction side (310) of the blade (30).

4. The blade vibration suppression device according to claim 3, characterized in that: The wind-raising concave surface (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.

5. The blade vibration suppression device according to claim 1, characterized in that: After passing through the blades (30), the external airflow enters the ventilating concave surface (110), so that a negative pressure area is formed on the side of the ventilating concave surface (110) facing away from the blades.

6. The blade vibration suppression device according to claim 1, characterized in that: There are a plurality of wind blocking members, which can be arranged at intervals along the span direction of the blade (30).

7. The blade vibration suppression device according to claim 1, characterized in that: The wind blocking member is provided with a plurality of ventilation holes (120) for adjusting the wind resistance of the wind blocking member (10).

8. The blade vibration suppression device according to any one of claims 1 to 7, characterized in that: The wind blocking member (10) is made of a flexible material.

9. The blade vibration suppression device according to claim 8, characterized in that: The wind blocking member (10) is a flexible sheet, and the connecting member (20) is a binding rope, which is fixedly connected to the flexible sheet and can fix the flexible sheet on the blade (30) and enable the flexible sheet to form a bag with an air inlet opening on the surface of the blade (30). Under the action of external airflow, the flexible sheet can be expanded.

10. The blade vibration suppression device according to claim 9, characterized in that: The binding ropes include cross binding ropes (210) and annular binding ropes (220); the flexible sheet is roughly square, and its two ends are respectively wrapped around the pressure side (320) and the suction side (310) of the blade (30); two corners of the flexible sheet are located on the pressure side (320) of the blade (30), and the other two corners are located on the suction side (310) of the blade (30); on each side of the pressure side (320) and the suction side (310), the cross binding ropes (210) bring the two corners of the flexible sheet closer to each other, thereby forming an air inlet opening between the two corners of the flexible sheet; the annular binding ropes (220) are connected to the two side edges of the middle part of the flexible sheet, and are wrapped around the circumference of the blade (30) to prevent the flexible sheet from moving in the extension direction of the blade (30).

11. The blade vibration suppression device according to claim 8, characterized in that: The blade vibration suppression device also includes a bracket, which is located inside the wind-absorbing concave surface (110) of the wind-blocking member (10) and is used to open the wind-blocking member made of a flexible material.

12. A blade assembly, comprising a blade (30), characterized in that: The blade assembly further comprises a blade vibration suppression device as claimed in any one of claims 1 to 11, wherein the blade vibration suppression device is installed on the leading edge side (340) and / or the trailing edge side (330) of the blade (30).

13. The blade assembly according to claim 12, wherein: The blade vibration suppression device is installed within a range of 85% to 95% in the span direction of the blade (30).

14. The blade assembly according to claim 12, wherein: The blade vibration suppression device is installed at one end close to the blade tip of the blade (30), and the distance between the wind blocking member (10) and the blade tip is greater than or equal to 2 m and less than or equal to 10 m.

15. The blade assembly according to claim 12, characterized in that The wind blocking member (10) overlaps the blade portion and can cover 50% to 80% of the chord-wise width of the blade (30).

16. The blade assembly according to claim 12, characterized in that There are a plurality of blade vibration suppression devices, which are arranged at intervals along the span direction of the blade (30), and the distance between two adjacent blade vibration suppression devices is 20 cm-50 cm; and / or The width of each wind blocking member in the span direction of the blade (30) is 1m-4m; and / or The laying width of the blade vibration suppression device in the span direction of the blade (30) is 8m to 10m.

17. A wind turbine generator set, characterized in that: The wind turbine generator set comprises the blade assembly according to any one of claims 12-16.

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