Design method and design device for blade and pneumatic accessory of blade

Abstract

The invention provides a design method and a design device for a blade and a pneumatic accessory thereof. The design method comprises the steps that current design parameters of the pneumatic accessory are determined; pneumatic data of the blade are obtained, and pneumatic accessories with current design parameters are installed in the trailing edge area of the blade; calculating a wind speed-power curve and a wind speed-damping ratio curve of the current wind generating set according to the pneumatic data; and determining the current design parameter as a final design parameter of the pneumatic accessory in response to the situation that the power generation amount determined according to the wind speed-power curve is greater than or equal to a preset value and the pneumatic damping determined according to the wind speed-damping ratio curve does not have a negative value. The pneumatic accessory designed according to the design method can improve the generating capacity of a unit, greatly reduce vibration, improve the performance of the unit and prolong the service life of the unit.

Description

Technical Field

[0001] The present disclosure generally relates to the field of wind power, and more specifically, to a design method and a design device for a blade and its aerodynamic accessories. Background Art

[0002] The blades of a wind turbine (abbreviated as a unit, fan, etc.) are the main components of the fan to capture wind energy. The aerodynamic shape, airfoil and specific structure of the blades are the main factors that determine the aerodynamic performance of the blades. During the structural design of the blades, it is necessary to iteratively optimize the aerodynamic performance of the blades while meeting safety, noise, vibration and other requirements. However, when these requirements are met, the aerodynamic performance of the blades will not be optimal.

[0003] Generally, spoiler nets, vortex generators, flaps, etc. are installed on the blades to improve vibration, reduce stall, increase power generation, etc. However, with the continuous increase in the capacity of wind turbines and the diversification of wind turbine models, challenges are brought to the structural design and installation position determination of the aerodynamic accessories installed on the blades.

[0004] Currently, there is no clear optimization design method for aerodynamic attachments on wind turbine blades, and current wind turbines that include blades with aerodynamic attachments still have much room for improvement in terms of power generation, operating life or vibration reduction. Summary of the invention

[0005] One of the objects of exemplary embodiments of the present disclosure is to overcome at least one of the above-mentioned technical problems.

[0006] One of the purposes of exemplary embodiments of the present disclosure is to provide a method for designing a pneumatic accessory.

[0007] According to one aspect of the present disclosure, a method for designing an aerodynamic attachment of a blade includes: determining current design parameters of the aerodynamic attachment; acquiring aerodynamic data of the blade, wherein an aerodynamic attachment having the current design parameters is installed in a trailing edge region of the blade; calculating a wind speed-power curve and a wind speed-damping ratio curve of a current wind turbine generator set based on the aerodynamic data; and determining the current design parameters as final design parameters of the aerodynamic attachment in response to a power generation amount determined based on the wind speed-power curve being greater than or equal to a predetermined value and aerodynamic damping determined based on the wind speed-damping ratio curve not having a negative value.

[0008] According to a second aspect of the present disclosure, a design device for aerodynamic accessories of a blade includes: a design parameter adjustment module, which determines the current design parameters of the aerodynamic accessories; an aerodynamic data acquisition module, which acquires the aerodynamic data of the blade, wherein the trailing edge region of the blade is installed with aerodynamic accessories having the current design parameters; a curve calculation module, which calculates the wind speed-power curve and the wind speed-damping ratio curve of the current wind turbine generator set based on the aerodynamic data; and a design parameter determination module, which determines the current design parameters as the final design parameters of the aerodynamic accessories in response to the power generation determined according to the wind speed-power curve being greater than or equal to a predetermined value and the aerodynamic damping determined according to the wind speed-damping ratio curve not having a negative value.

[0009] According to a third aspect of the present disclosure, a computer-readable storage medium stores instructions or programs, which, when executed by a processor, prompt the processor to execute the above-mentioned design method.

[0010] According to a fourth aspect of the present disclosure, a design device for aerodynamic attachments of a blade includes a processor and a memory, wherein the memory stores instructions or programs, and when the instructions or programs are executed by the processor, the processor is prompted to execute the above-mentioned design method.

[0011] According to a fifth aspect of the present disclosure, there is provided a blade having a trailing edge region equipped with an aerodynamic attachment so that the pressure center of the airfoil corresponding to the installation position of the aerodynamic attachment moves toward the leading edge of the blade.

[0012] According to a sixth aspect of the present disclosure, a wind turbine generator set includes the above-mentioned blade.

[0013] The blade designed according to the design method of the embodiment of the present disclosure can move the pressure center of the airfoil corresponding to the installation position of the aerodynamic attachment toward the leading edge of the blade.

[0014] The blades according to the embodiments of the present disclosure can improve the power generation of the unit, eliminate large-amplitude vibrations, and increase the performance and service life of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects and features of the exemplary embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings which exemplarily illustrate the embodiments, in which:

[0016] Figure 1 is a schematic diagram of a blade airfoil according to an embodiment of the present disclosure;

[0017] Figure 2 1 is a schematic diagram showing the force of a fan blade element;

[0018] Figure 3 It is a schematic diagram showing the principle of pitch moment of a fan blade;

[0019] Figure 4is a graph showing the variation of the pitching moment coefficient with the angle of attack;

[0020] Figure 5 is a schematic diagram showing the calculation principle of the torsional deformation of the fan blade;

[0021] Figure 6 is a scatter diagram showing the distribution of the torsional deformation of the fan blade along the span direction;

[0022] Figure 7 is a scatter plot showing the decrease in the power curve of the wind turbine due to the torsional deformation of the blades;

[0023] Figure 8 is a graph showing the aerodynamic damping ratio of a blade as a function of wind speed;

[0024] Fig. 9 is a schematic diagram showing design parameters of a blade according to an embodiment of the present disclosure;

[0025] Fig.10 is a schematic diagram showing design parameters of a blade according to an embodiment of the present disclosure;

[0026] Fig.11 is a schematic diagram showing the installation positions of multiple parts of the aerodynamic attachment in the airfoil span direction according to an embodiment of the present disclosure;

[0027] Fig.12 is a schematic diagram showing the position of the pressure center and the aerodynamic pitching moment of the original airfoil;

[0028] Fig.13 is a schematic diagram showing the forward shift of the airfoil pressure center after the aerodynamic attachment is installed on the trailing edge of the blade;

[0029] Fig.14 is a graph of the pitch moment coefficient before and after the aerodynamic attachment device is installed on the trailing edge of the blade;

[0030] Fig.15 is a flow chart showing a method for designing a pneumatic attachment according to a first embodiment of the present disclosure;

[0031] Fig.16 is a flow chart illustrating a method for designing a pneumatic attachment according to a second embodiment of the present disclosure;

[0032] Fig.17 is a flow chart illustrating a method for designing a pneumatic attachment according to a third embodiment of the present disclosure;

[0033] Fig.18 is a graph showing the change of aerodynamic damping ratio with wind speed before and after the installation of aerodynamic accessories;

[0034] Fig.19 is a power curve after installing the pneumatic accessory according to an embodiment of the present disclosure;

[0035] Fig. 20 is a block diagram illustrating a design apparatus for a pneumatic attachment according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] The following detailed description is provided to help gain a comprehensive understanding of the methods, devices and / or systems described herein. However, the order of operations described herein is only an example and is not limited to those orders set forth herein, but may be equivalently replaced or changed except for operations that must occur or be performed in a specific order. In addition, for greater clarity and simplicity, the description of content known in the art will be omitted or simplified.

[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by a person of ordinary skill 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 a general dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0038] Unless otherwise specified, the same reference numerals generally refer to the same elements (e.g., components, steps, and methods). Reference numerals described in the previous embodiments may be omitted if they appear again in the subsequent embodiments. In addition, the technical features described in different or the same embodiments may be combined in any manner, as long as the combined embodiments or technical solutions are complete and can solve the technical problems of the present application or achieve the technical effects described or not described in the present application but can be determined based on the above complete technical solutions.

[0039] Torsional deformation of the blades in the negative direction can lead to a decrease in wind turbine performance and negative damping within a specific wind speed range (the aerodynamic damping ratio and aerodynamic damping coefficient are negative). The present invention controls the pitch moment coefficient by installing aerodynamic accessories on the blades, thereby compensating for the lost power generation and improving the aerodynamic damping of the blades at the operating wind speed (for example, the aerodynamic damping ratio).

[0040] The aerodynamic attachment of the present disclosure can be installed in the trailing edge area of ​​the blade, thereby enabling the pressure center of the airfoil corresponding to the aerodynamic attachment to be moved toward the leading edge, and the blade element has a "lifting head" tendency (increasing the angle of attack to compensate for the torsional deformation in the negative direction). The following is a brief explanation and description of the terms that may be involved in the present disclosure.

[0041] Pitch angle adjustment type wind turbine: During operation, when the output power is less than the rated power, the pitch angle remains unchanged at zero degrees without any adjustment; when the generator output power reaches the rated power, the adjustment system adjusts the pitch angle according to the change in output power to keep the generator output power at the rated power. At this time, the control system participates in the adjustment to form a closed-loop control.

[0042] Annual power generation: The total power generated by a wind turbine in one year, which is the integral of power × Weibull distribution × number of generating hours.

[0043] Blade in-plane direction: the direction of rotation of the fan blades.

[0044] Blade out-of-plane direction: the direction perpendicular to the plane of rotation of the fan blade.

[0045] Spanwise or spanwise direction: The direction from the blade root to the blade tip.

[0046] Blade airfoil: The aerodynamic profile of a blade section at a predetermined spanwise position.

[0047] Center of pressure: The position where the pitching moment formed by the aerodynamic distributed load is relative to zero, that is, the resultant force of lift and drag has no moment about this point.

[0048] Shear center: The position where distributed load does not produce torsional deformation, also known as the bending center.

[0049] Pressure surface: The side of an object's surface where the fluid has higher pressure. Usually, when the fluid flows through an object, due to the shape of the object's surface and the viscosity of the fluid, the fluid will encounter resistance, resulting in an area of ​​pressure distribution on the object's surface. On the pressure surface, the fluid's speed is slower and the pressure is higher.

[0050] Suction surface: Due to the shape of the surface and the viscosity of the fluid, the fluid will experience resistance, resulting in an area of ​​suction distribution on the surface of the object, usually associated with higher speeds and lower static pressure.

[0051] Chord Line: The straight line connecting the leading and trailing edges of a blade.

[0052] Skin: The composite reinforcement that maintains the blade's geometry, provides the aerodynamic shape and carries most of the shear loads.

[0053] Pitch axis: A straight line from the center point of the blade root pitch circle to the blade side, perpendicular to the blade pitch circle plane, with the direction from the blade root to the blade tip being positive.

[0054] Trailing Edge / Trailing Edge: The point at the rear end of the airfoil with the greatest curvature.

[0055] Leading Edge: The point at the front of the airfoil where the curvature is greatest.

[0056] Blade element: A cross section of the blade shape along the span direction.

[0057] Aerodynamic twist angle: The twist angle at any spanwise position of the blade refers to the difference between the local pitch angle and the blade tip pitch angle.

[0058] Pitch angle: generally refers to the angle between the rotor rotation plane and the airfoil chord line at any spanwise position of the blade.

[0059] Lift: The component of aerodynamic force perpendicular to the incoming flow velocity, which is positive when pointing toward the suction surface.

[0060] Drag: The component of aerodynamic force parallel to the incoming flow velocity, which is positive if it is in the same direction as the velocity.

[0061] Swinging direction: perpendicular to the direction of rotation of the wind wheel, with downwind direction being positive.

[0062] Oscillation direction: parallel to the direction of the wind wheel rotation plane, clockwise is positive.

[0063] Axial induction factor: A dimensionless coefficient that characterizes the magnitude of the velocity loss after the wind passes through the impeller.

[0064] Tangential induction factor: A dimensionless coefficient that characterizes the rotational speed obtained after the wind passes through the impeller.

[0065] Blade element momentum theory: momentum theory and force balance of two-dimensional airfoil, a method to solve the momentum equation which is closed.

[0066] Bending-torsion coupling: When the blade is in a deformed state, it is subjected to lateral loads, which produces torsion, thereby changing the angle of attack and reversely affecting the aerodynamic force. The aerodynamic force and structure are iterated through the variable of the angle of attack.

[0067] Wind rotor power: the part of wind energy passing through the wind rotor system per unit time that is converted into wind rotor kinetic energy by the wind rotor system.

[0068] Blade root coordinate system: a right-handed coordinate system consisting of the blade flapping-shimmy-pitch axis with the midpoint of the blade root pitch circle as the origin.

[0069] Main beam: The main load-bearing structure of the blade, which is made of fiber and matrix infusion to provide support for the cavity structure of the blade.

[0070] Clearance: The distance between a certain section of the blade and the tower wall when the blade is in a deformed state.

[0071] Pre-bending: When the blades are stationary, the neutral axis is in the swinging direction, away from the pitch axis. The purpose is to increase the tower clearance and reduce the risk of the blades colliding with the tower after deformation.

[0072] Chord length coordinate system: The coordinate origin is located at the aerodynamic center (25% chord length position), the Y-axis direction is from the leading edge to the trailing edge, and the X-axis is the normal direction of the chord length.

[0073] Leading edge coordinate system: The coordinate origin is located at the starting point of the leading edge, the Y-axis direction is from the leading edge to the trailing edge, and the X-axis is the normal direction of the chord length.

[0074] Trailing edge local coordinate system: On the suction surface of the airfoil, a local coordinate system is established, with the origin of the coordinate system located near the trailing edge of the suction surface, the Y axis pointing to the tangent direction of the arc length of the suction surface (the tangent direction of the curve from the trailing edge to the leading edge), and the X axis pointing to the normal direction of the curve from the trailing edge to the leading edge;

[0075] Pitch moment coefficient: The airfoil is fixed at the 25% chord length position, and a wind tunnel test is conducted. At the same time, the force on the airfoil is measured by a force balance. The relationship between the force and the incoming flow velocity, air density, and chord length can be described by the pitch moment coefficient. There is a a =0.5·ρc 2 C m V 2 (Where Ma is the pitching moment, ρ is the air density, c is the chord length, and V is the wind speed).

[0076] Vibration mode: The form in which a system vibrates, regardless of the magnitude of the vibration displacement.

[0077] Vibration node: also called mechanical vibration mode node. Mode node refers to the intersection node of the mode shape and the original shape of the structure at a certain natural frequency. The amplitude at the mode node is zero.

[0078] Space: The distance from the airfoil to the blade root in the length direction of the blade.

[0079] Damping ratio: Damping ratio refers to the ratio of the damping coefficient to the critical damping coefficient, which expresses the standardized damping size of the structure.

[0080] Self-excited vibration: The vibration caused by the internal fluid of a mechanical system changing from non-vibrational excitation to vibrational excitation. It corresponds to negative damping in the vibration differential equation.

[0081] Aerodynamic damping or aerodynamic damping ratio: The fluid hinders the structure and consumes energy. This aerodynamic parameter that affects the vibration of the structure is called aerodynamic damping or aerodynamic damping ratio.

[0082] Flutter: The bending-torsion coupled deformation of the blade produces self-excited vibration under the action of aerodynamic force. In this state, the aerodynamic damping of the blade is negative and the blade vibration diverges exponentially.

[0083] Figure 1 is a schematic diagram of a blade airfoil according to an embodiment of the present disclosure.

[0084] Figure 1FIG. 4 shows a cross-sectional view taken along the chord direction of the blade. The blade airfoil of the wind turbine generator set according to the embodiment of the present disclosure may be as follows: Figure 1 As shown, the relative positions of the leading edge 1, the trailing edge 2, the chord length 3, the pressure surface 5 and the suction surface 4 of the blade can be determined by the geometric dimensions of the airfoil.

[0085] The aerodynamic attachment according to the embodiment of the present disclosure can be installed in the trailing edge area of ​​the blade so that the pressure center of the airfoil corresponding to the installation position of the aerodynamic attachment moves toward the leading edge of the blade. Figures 2 to 13 This is described in detail.

[0086] Figure 2 It is a schematic diagram showing the force of the fan blade element. Figure 3 It is a schematic diagram showing the principle of pitch moment of the fan blade. Figure 4 is the pitch moment coefficient C m The curve graph of the change with the angle of attack, Figure 5 It is a schematic diagram showing the calculation principle of the torsional deformation of the fan blade. Figure 6 is a scatter plot showing the distribution of the torsional deformation of the fan blade along the span direction. Figure 7 It is a scatter plot showing the decrease in the power curve of the wind turbine due to the torsion deformation of the blades. Figure 8 is a graph showing the aerodynamic damping ratio of the blade as a function of wind speed, Fig. 9 is a schematic diagram showing design parameters of a blade according to an embodiment of the present disclosure, Fig.10 is a schematic diagram showing design parameters of a blade according to an embodiment of the present disclosure, Fig.11 Schematic diagram showing installation positions of multiple parts of an aerodynamic accessory in an airfoil span direction according to an embodiment of the present disclosure.

[0087] like Figure 2 As shown, according to an embodiment of the present disclosure, a blade element at a predetermined position along the span direction of a blade of a wind turbine generator set generates an inflow angle γ under the action of wind speed V, and its magnitude can be expressed by the following formula (1):

[0088] γ=arctan[V(1-a) / Ωr(1+b)] (1)

[0089] Where a and b are the axial and tangential induction factors, respectively, and Ω is the blade speed. At the same time, the inflow angle γ can be expressed by the following formula (2):

[0090] γ=θ p +θ a +φ+α (2)

[0091] Among them, θ p is the pitch angle, θ arepresents the aerodynamic twist angle, φ is the torsional deformation, and α is the angle of attack of the blade element. According to the blade element momentum theory, at an angle of attack of α, the blade element generates lift dL and drag dD, and its projection forces in the X-axis and Y-axis directions are dF a and dF t .

[0092] like Figure 3 As shown in the figure, the lift and drag of the blade element at the angle of attack α are F L and F D , whose resultant force is vector F sum , the resultant force acts on the pressure center of the airfoil, and its projection on the chord length coordinate system is the normal force F a and the tangential force F t . Lift F L , resistance F D and the normal force F a , tangential force F t There is a relationship shown in the following formula (3):

[0093]

[0094] Since the aerodynamic center is located at 25% of the chord length, assume that the distance from the airfoil pressure center to the aerodynamic center in the leading edge coordinate system is d y , pitching moment M a for:

[0095]

[0096] Among them, C m is the pitch moment coefficient, through C m As the angle of attack changes, we can get d y , and then d y Add 25% × c to obtain the absolute position of the center of pressure in the leading edge coordinate system.

[0097] d y =-M a / (cosα·F L +sinα·F D ) (5)

[0098] like Figure 4 As shown in the figure, for the blades of a wind turbine, the angle of attack of the operating section ranges from -5° to 15°. In this operating section, the pitch moment coefficient C m For negative values, the center of pressure is located after 25% of the chord length.

[0099] After determining the pressure center position of each section under specific working conditions, the aerodynamic torque generated by the i+1th section on the ith section is:

[0100] like Figure 5 As shown, its size is determined by the pressure center position of the i+1th section and the shear center position of the ith section, and its value can be determined by the following formula (6):

[0101]

[0102] For the blades of wind turbines, there are Therefore, the blades produce a downward deformation (i.e., they deform in the direction of reducing the angle of attack).

[0103] The distribution of the torsional deformation of each section of the blade along the span direction is as follows: Figure 6 As shown in the figure, under normal working conditions, the torsional deformation of each section of the blade shows a decreasing trend in the span direction, and the torsional deformation of the blade tip is close to -6°. The torsional deformation in the negative direction causes each airfoil to deviate from the optimal lift-drag ratio, seriously affecting the aerodynamic performance of the blade.

[0104] In addition, if Figure 7 As shown, when the pressure center of the airfoil of a wind turbine blade is located in front of the shear center of its previous cross-sectional position (closer to the leading edge), it produces a nose-down deformation, which reduces the angle of attack and causes the blade to deviate from the established aerodynamic design point, resulting in a lower power curve and a loss of power generation.

[0105] Furthermore, if Figure 8 As shown in the figure, when the wind turbine blades have a low head deformation, the impeller system will have self-excited vibration in a certain wind speed range, which can be described by the parameter of aerodynamic damping ratio (aerodynamic damping). When the curve of aerodynamic damping changing with wind speed is lower than 0, the wind turbine has an unstable wind speed range. The blades operate in this wind speed range with a large vibration amplitude, and are easily damaged by the structure.

[0106] However, if Fig. 9 As shown, the trailing edge area of ​​the airfoil is AA, and the trailing edge point of the airfoil is O 1 , along the suction surface, O 1 Mobile 2 Distance to point O 2 , with O 2 Establish the local coordinate system of the trailing edge as the coordinate origin, where X L The positive direction is O 1 to 2 Tangent to the curve, Y L The positive direction is O 1 to 2 The normal of the curve. 2 Point is the origin, install pneumatic accessories and X L The axis is at an angle β (i.e., the installation angle), the thickness of the pneumatic attachment is t, and the width of the pneumatic attachment is l1 Adding aerodynamic accessories to the airfoil surface can change the pressure distribution on the airfoil pressure and suction surfaces, making the lift coefficient C l or C L Drop, drag coefficient C d or C D Ascent, pitch moment coefficient C m Increase.

[0107] like Fig.10 As shown, the length of the blade is L, and the distance from the starting installation position of the pneumatic attachment to the blade root is L 1 The distance between the terminal installation position of the pneumatic accessories and the blade root is L 2 The length of the pneumatic attachment is d (which can be obtained by d = L 2 -L 1 Approximate calculations).

[0108] The thickness t of the aerodynamic attachment, the chord length c of the blade, the length L of the blade, and the distance L from the starting position of the aerodynamic attachment along the span of the blade to the blade root 1 , installation angle β of pneumatic accessories, width l of pneumatic accessories 1 , the length l of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge region in the cross section in the chord direction of the blade 2 , the distance L from the end position of the aerodynamic attachment installed along the span direction of the blade to the blade root 2 At least one of the following equations (7) to (12) may be satisfied:

[0109]

[0110]

[0111] l 1 ∈[0.5%×c,5%×c] (9)

[0112] l 2 ∈[0,10%×c] (10)

[0113] β∈[90°,185°] (11)

[0114] t∈[0.1cm,1.5cm] (12)

[0115] When the above conditions are met, both aerodynamic damping and power generation can be improved. Specifically, when L 1 and L 2 When the above conditions are met, vibration can be significantly reduced, and when the installation angle β meets the above conditions, aerodynamic damping can be significantly improved.

[0116] Although Fig. 9The pneumatic accessories are shown in the figure as being installed on the pressure surface, but the pneumatic accessories can also be installed on the suction surface, that is, the pneumatic accessories according to the embodiments of the present disclosure can be installed on at least one of the suction surface and the pressure surface of the trailing edge area of ​​the blade. The relevant parameters of the pneumatic accessories installed on the pressure surface are similar to those of the pneumatic accessories installed on the suction surface, and will not be repeated here. The pneumatic accessories are installed on both the pressure surface and the suction surface at the same time, and the pressure center is controlled by the different sizes and the starting installation positions. The specific installation positions (O 2 ) can be obtained through l 2 Sure.

[0117] As an example, the pneumatic attachment may not adopt an integral configuration, for example, a segmented multi-segment configuration, and the pneumatic attachment installation angle, initial installation position, attachment length, and thickness between each segment may be designed separately. In other words, the pneumatic attachment may include a plurality of pneumatic parts spaced apart from each other along the span direction.

[0118] For details, please refer to Fig.11 The lengths of the two adjacent aerodynamic parts are d 1 and d 2 , the installation interval between two adjacent pneumatic parts is Δd, which can satisfy d = d 1 +d 2 +Δd. The length d and the spacing (installation interval) Δd of the aerodynamic accessories along the blade span direction may satisfy Δd<1 / 5d.

[0119] The pneumatic attachment and the mounting surface of the pneumatic attachment on the blade (for example, the pressure surface and / or the suction surface) have a chamfer, and the chamfer design can enhance the effect of the pneumatic attachment on improving the blade performance. The pneumatic attachment may not adopt a straight geometric configuration, but may adopt an arc-shaped geometric configuration with a certain curvature.

[0120] Furthermore, the cross section of the aerodynamic attachment in the chordwise direction of the blade according to the embodiment of the present disclosure may have a rectangular shape, but this is merely an example and the cross section of the aerodynamic attachment in the chordwise direction of the blade is not particularly limited.

[0121] The material of the pneumatic attachment according to the embodiment of the present disclosure may include at least one of aluminum alloy, carbon fiber and fiberglass. As an example, the material of the pneumatic attachment may not be plastic, but aluminum alloy, carbon fiber, fiberglass or a metal material such as structural steel. In addition, during installation, the pneumatic attachment may be fixed to the blade by bolts. Compared with installing the pneumatic attachment by a bonding process, fixing the pneumatic attachment by bolts can more firmly fix the pneumatic attachment.

[0122] Fig.12 is a schematic diagram showing the position of the pressure center and the aerodynamic pitching moment of the original airfoil. Fig.13is a schematic diagram showing the forward shift of the airfoil pressure center after the aerodynamic attachment is installed on the trailing edge of the blade. Fig.14 is a graph of the pitch moment coefficient before and after the aerodynamic attachment device is installed on the trailing edge of the blade.

[0123] like Fig.12 As shown, before the aerodynamic attachment of the present invention is installed, the center of action of the aerodynamic load on the original airfoil surface is located behind the shear center of the airfoil, that is, closer to the trailing edge of the blade. At this time, the aerodynamic load generates an aerodynamic moment relative to the shear center that causes the leading edge of the blade to sink.

[0124] like Fig.13 As shown, after the aerodynamic attachment of the present invention is installed, the aerodynamic load distribution on the airfoil surface is properly adjusted. At this time, the pressure center of the airfoil is located at the upwind position of the shear center, that is, closer to the leading edge of the blade. The aerodynamic load generates an aerodynamic moment relative to the shear center that causes the leading edge of the blade to rise.

[0125] like Fig.14 As shown, after installing the pneumatic attachment of the present invention, the pitch moment coefficient is significantly increased within the operating angle of attack range of the blade, that is, the pressure center moves toward the leading edge. The design method of the pneumatic attachment of the present invention is described in detail below.

[0126] Fig.15 is a flow chart illustrating a method for designing a pneumatic attachment according to a first embodiment of the present disclosure.

[0127] Reference Fig.15 , the design method of a pneumatic accessory according to an embodiment of the present disclosure may include step S1510, step S1520, step S1530 and step S1540.

[0128] In step S1510, the current design parameters of the pneumatic attachment are determined. The design parameters of the pneumatic attachment may be as described above, for example, the length d of the pneumatic attachment, the thickness t of the pneumatic attachment, the distance L from the starting position of the pneumatic attachment to the blade root along the span direction of the blade, 1 , installation angle β of pneumatic accessories, width l of pneumatic accessories 1 , the length l of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge region in the cross section in the chord direction of the blade 2 , the distance L from the end position of the aerodynamic attachment installed along the span direction of the blade to the blade root 2 At least one of .

[0129] In step S1520, aerodynamic data of the blade is obtained, where the aerodynamic data is aerodynamic data when aerodynamic accessories with current design parameters are installed in the trailing edge area of ​​the blade, and the aerodynamic data may include lift coefficient, drag coefficient, wind speed, air density, pitch moment coefficient, etc. For example, the aerodynamic data may include at least one of the lift coefficient, drag coefficient, and pitch moment coefficient.

[0130] In step S1530, the wind speed-power curve and the wind speed-damping ratio curve of the current wind turbine generator set are calculated according to the aerodynamic data.

[0131] The wind speed-power curve and the wind speed-damping ratio curve can be calculated by existing methods. For example, the power at a predetermined wind speed can be calculated by the following formula (13), thereby obtaining a power curve.

[0132]

[0133] Among them, a, b are the axial induction factor and tangential induction factor respectively, V is the wind speed, r is the distance from the spanwise section of the blade to the center of the hub, R is the distance from the center of the hub to the tip of the blade, ρ is the air density, A is the swept area of ​​the impeller, λ is the tip speed ratio, and its expression is:

[0134]

[0135] Among them, Ω is the angular velocity of the wind turbine, R is the rotation radius of the wind wheel, and V is the wind speed.

[0136] In addition, the induced axial induction factor a and the tangential induction factor b can be obtained by solving the nonlinear equations shown in equations (15) and (16):

[0137]

[0138]

[0139] Among them, C t , C n are the axial thrust coefficient and the normal thrust coefficient respectively, σ is the impeller solidity, γ is the inflow angle, C t and C n It can be specifically determined by the following equations (17) to (20).

[0140] C n =C l cosγ+C d sinγ (17)

[0141] C t =C l sinγ-C d cosγ (18)

[0142]

[0143] The inflow angle γ can be calculated by the above formula (1), c is the blade chord length, C l , C d are the lift coefficient and drag coefficient of the blade element, which can be found out by calculating the blade element power angle α, and B refers to the number of blades.

[0144] α=γ-θ p -θ a +θ s (20)

[0145] Among them, θ a is the aerodynamic twist angle of the blade element, θ p is the pitch angle, θ s is the torsional deformation of the blade element cross section, and all three can be determined in advance.

[0146] The wind speed-damping ratio curve (i.e., the curve in which the aerodynamic damping changes with wind speed) can be determined by the following equations (21) to (27).

[0147]

[0148]

[0149]

[0150]

[0151] In equations (21) to (24), W is the incoming flow received by the blade element, which can be expressed by Determine, where V is the wind speed, Ω is the rotation speed of the wind wheel, and r is the rotation radius of the wind wheel.

[0152] The aerodynamic damping of the impeller as a whole can be determined by equations (25) to (27).

[0153]

[0154]

[0155]

[0156] The real part of formula (27) is the aerodynamic damping of the impeller as a whole, C a is the aerodynamic damping matrix, λ is the eigenvalue and can be obtained by solving equation (26), I is the unit matrix, K is the stiffness matrix, M is the damping matrix, and C sis the structural damping, where the stiffness matrix K, damping matrix M and structural damping Cs are known quantities that can be determined by finite element calculation.

[0157] The above method of calculating the power and aerodynamic damping at a predetermined wind speed is only an example, and the above calculation formula may be simplified, approximated, etc., or other methods may be used for calculation.

[0158] In step S1540, in response to the power generation determined according to the wind speed-power curve being greater than or equal to a predetermined value and the aerodynamic damping determined according to the wind speed-damping ratio curve not having a negative value, the current design parameters are determined as final design parameters of the aerodynamic attachment.

[0159] Taking the annual power generation as an example, the power generation can be calculated based on the product of the duration (hours) of each wind speed segment in a year and the power at the corresponding wind speed. In addition, the aerodynamic damping (aerodynamic damping ratio) of a predetermined wind speed interval (e.g., the full wind speed segment) can be determined based on the wind speed-damping ratio curve. If the aerodynamic damping in the wind speed interval does not have a negative value, the current design parameters can be determined as the final design parameters of the pneumatic attachment.

[0160] Fig.16 is a flow chart illustrating a method for designing a pneumatic attachment according to a second embodiment of the present disclosure.

[0161] In the parameter design process of pneumatic accessories, it is necessary to constantly adjust the design parameters of pneumatic accessories. Fig.16 In addition to steps S1510 to S1540, the design method according to an embodiment of the present disclosure may further include step S1550.

[0162] In step S1550, in response to the power generation determined according to the wind speed-power curve being less than a predetermined value or the aerodynamic damping determined according to the wind speed-damping ratio curve having a negative value, current design parameters of the aerodynamic accessories are adjusted and the adjusted design parameters are used as current design parameters.

[0163] The design parameters can be adjusted continuously until the aerodynamic damping and power generation both meet the design requirements. When adjusting the design parameters, a part of the design parameters can be adjusted and fixed first, and then other design parameters can be adjusted until the aerodynamic damping and power generation both meet the design requirements.

[0164] The predetermined value here may be a predetermined power generation threshold. When adjusting the design parameters of the pneumatic attachment, a part of the design parameters of the pneumatic attachment may be adjusted first to make the pneumatic damping meet the design requirements, and then other design parameters may be adjusted to make the power generation meet the requirements.

[0165] Fig.17 is a flow chart illustrating a method for designing a pneumatic attachment according to a third embodiment of the present disclosure.

[0166] In response to the power generation determined according to the wind speed-power curve being less than a predetermined value or the aerodynamic damping determined according to the wind speed-damping curve ratio having a negative value, the current design parameters of the pneumatic accessories are adjusted, and the step of using the adjusted design parameters as the current design parameters may include step S1551 and step S1552.

[0167] In step S1551 , in response to the aerodynamic damping determined according to the wind speed-damping ratio curve having a negative value, the installation angle β of the aerodynamic attachment is adjusted so that the aerodynamic damping does not have a negative value.

[0168] In step S1552, in response to the aerodynamic damping not having a negative value and the power generation determined according to the wind speed-power curve being less than a predetermined value, the length d of the aerodynamic attachment, the distance L from the starting position of the aerodynamic attachment to the blade root along the span direction of the blade are adjusted. 1 , Width of pneumatic attachments l 1 , the length l of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge region in the cross section in the chord direction of the blade 2 At least one of .

[0169] When adjusting d, L 1 , l 1 , l 2 When you need to adjust d, L 1 and l 2 , and finally adjust the width l of the pneumatic attachment 1 As a result, the power generation and aerodynamic damping can reach the design requirements more quickly.

[0170] Specifically, the design method of the pneumatic attachment according to the embodiment of the present disclosure may further include initially determining the length d of the pneumatic attachment and the distance L from the starting position of the pneumatic attachment to the blade root along the span direction of the blade according to the vibration mode of the blade when the pneumatic attachment is not installed. 1 For example, the aerodynamic attachment may be installed at a position where the vibration amplitude of the blade is the largest, for example, from the middle of the blade to the tip.

[0171] Fig.18 is a graph showing the change of aerodynamic damping ratio with wind speed before and after the installation of aerodynamic accessories. Fig.19 is a power curve after installing the pneumatic accessories according to the embodiment of the present disclosure.

[0172] After installing the pneumatic accessories disclosed in the present invention, the calculation results of the pneumatic damping of the fan at all wind speeds are as follows: Fig.18 As shown. Fig.18 It can be seen that the pneumatic accessories according to the embodiments of the present disclosure achieve the goal of no negative aerodynamic damping in all wind speed ranges by adjusting the aerodynamic load distribution, thereby fundamentally solving the aforementioned problem of blade in-plane vibration caused by negative aerodynamic damping.

[0173] In addition, after the aerodynamic attachment of the present disclosure is installed, the position of the pressure center in the airfoil is changed. The torsional deformation of the blade in the direction of decreasing the angle of attack is effectively controlled, and the power curve after the aerodynamic attachment is installed is improved and closer to the ideal power curve (power curve without considering any deformation), such as Fig.19 As shown, the power curve has been optimized and the power generation has been improved by about 1%.

[0174] Fig. 20 is a block diagram illustrating a design apparatus for a pneumatic attachment according to an embodiment of the present disclosure.

[0175] The design device 2000 of a pneumatic attachment according to an embodiment of the present disclosure may include a design parameter adjustment module 2010 , a pneumatic data acquisition module 2020 , a curve calculation module 2030 , and a design parameter determination module 2040 .

[0176] The design parameter adjustment module 2010 can determine the current design parameters of the pneumatic accessory. As described above, the current design parameters may include d, L 1 , l 1 , l 2 , at least one of β.

[0177] The aerodynamic data acquisition module 2020 can acquire the aerodynamic data of the blades equipped with aerodynamic accessories. The aerodynamic data of the blades can be obtained by calculating using existing calculation methods, which will not be described in detail here.

[0178] The curve calculation module 2030 may calculate the wind speed-power curve and the wind speed-damping ratio curve of the current wind turbine generator set according to the aerodynamic data. The specific calculation method may be as described above.

[0179] The design parameter determination module 2040 may determine the current design parameters as final design parameters of the pneumatic attachment in response to the power generation determined according to the wind speed-power curve being greater than or equal to a predetermined value and the aerodynamic damping determined according to the wind speed-damping ratio curve not having a negative value.

[0180] The design parameter adjustment module 2010 may adjust the installation angle β of the pneumatic attachment so that the aerodynamic damping does not have a negative value in response to the aerodynamic damping determined according to the wind speed-damping ratio curve having a negative value. In addition, the design parameter adjustment module 2010 may also adjust the length d of the pneumatic attachment, the distance L from the starting position of the pneumatic attachment to the blade root along the span direction of the blade in response to the aerodynamic damping not having a negative value and the power generation determined according to the wind speed-power curve being less than a predetermined value. 1 , Width of pneumatic attachments l 1 , the length l of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge region in the cross section in the chord direction of the blade 2 At least one of .

[0181] When adjusting d, L 1 , l 1 , l 2 When d and L are adjusted 1 and l 2 , and finally adjust the width l of the pneumatic attachment 1 As a result, the power generation and aerodynamic damping can reach the design requirements more quickly.

[0182] The design method according to the embodiment of the present disclosure can be executed by a processor and can be written as a corresponding computer program or code. The design method, device, etc. according to the embodiment of the present disclosure have been described above with reference to the accompanying drawings. However, it should be understood that the devices and modules shown in the accompanying drawings can be configured as software, hardware, firmware or any combination of the above items to perform specific functions. For example, these systems and modules may correspond to dedicated integrated circuits, pure software codes, or modules that combine software and hardware. In addition, one or more functions implemented by these devices and modules may also be uniformly executed by components in physical entity devices (for example, processors, clients, servers, etc.).

[0183] The instructions stored in the above-mentioned computer-readable storage medium can be executed in an environment deployed in computer devices such as a client, a host, a proxy device, a server, etc. It should be noted that the instructions can also be used to execute additional steps in addition to the above-mentioned steps or to perform more specific processing when executing the above-mentioned steps. The contents of these additional steps and further processing have been mentioned in the description of relevant modules, methods and devices with reference to the accompanying drawings, so they will not be repeated here to avoid repetition.

[0184] It should be noted that the control method and control device according to the embodiments of the present disclosure can completely rely on the operation of computer programs or instructions to realize the corresponding functions, that is, each device corresponds to each step in the functional architecture of the computer program, so that the entire system is called through a special software package (for example, lib library) to realize the corresponding function.

[0185] On the other hand, when the device or system is implemented in software, firmware, middleware or microcode, the program code or code segment for performing the corresponding operation can be stored in a computer-readable medium such as a storage medium, so that at least one processor or at least one computing device can perform the corresponding operation by reading and running the corresponding program code or code segment. In addition, the computer-readable medium or storage medium can cause the processor to execute the above-mentioned design method when the computer program is executed by the processor.

[0186] For example, according to an exemplary embodiment of the present disclosure, a computer device including a readable medium storing computer program instructions may be provided, wherein when the instructions are executed by at least one computing device, the at least one computing device is prompted to perform at least one of the above steps.

[0187] According to an embodiment of the present disclosure, a computer-readable storage medium is provided, which stores instructions or programs. When the instructions or programs are executed by a processor, the processor is prompted to execute the above-mentioned design method.

[0188] Computer-readable storage media include non-transitory computer-readable storage media, for example, magnetic media such as floppy disks and tapes, optical media (including compact disks (CD) ROMs and DVD ROMs), magneto-optical media such as floppy disks, hardware devices such as ROMs, RAMs, and flash memories designed to store and execute program commands. The program commands include language codes executable by a computer using an interpreter and machine language codes generated by a compiler. The above-mentioned hardware devices can be implemented by one or more software modules for performing the operations of the various embodiments of the present disclosure.

[0189] According to an embodiment of the present disclosure, a design device for aerodynamic accessories of a blade is provided, the design device comprising a processor and a memory, the memory storing instructions or programs, which, when executed by the processor, prompt the processor to execute the above-mentioned design method.

[0190] According to an embodiment of the present disclosure, a wind turbine generator set is provided, and the wind turbine generator set includes the above-mentioned blade.

[0191] The blade designed according to the design method of the embodiment of the present disclosure can move the pressure center of the airfoil corresponding to the installation position of the aerodynamic attachment toward the leading edge of the blade.

[0192] The blades according to the embodiments of the present disclosure can improve the power generation of the unit, eliminate large-amplitude vibrations, and increase the performance and service life of the unit.

[0193] Although some exemplary embodiments of the present disclosure have been shown and described, it will be understood by those skilled in the art that modifications may be made to these embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents; for example, the technical features of different embodiments may be combined.

Claims

1. A method for designing a pneumatic attachment of a blade, characterized in that: The design method comprises: Determine current design parameters for pneumatic accessories; Acquiring aerodynamic data of a blade, wherein the aerodynamic attachment having current design parameters is installed in the trailing edge region of the blade; Calculate the wind speed-power curve and wind speed-damping ratio curve of the current wind turbine generator set according to the aerodynamic data; In response to the power generation determined according to the wind speed-power curve being greater than or equal to a predetermined value and the aerodynamic damping determined according to the wind speed-damping ratio curve not having a negative value, current design parameters are determined as final design parameters of the aerodynamic attachment.

2. The method for designing aerodynamic attachments of a blade according to claim 1, characterized in that: The design method further comprises: In response to the power generation determined according to the wind speed-power curve being less than the predetermined value or the aerodynamic damping determined according to the wind speed-damping ratio curve having a negative value, current design parameters of the aerodynamic accessory are adjusted and the adjusted design parameters are used as current design parameters.

3. The method for designing aerodynamic attachments of a blade according to claim 2, characterized in that: The design parameters include: at least one of the length d of the aerodynamic attachment, the distance L1 from the starting position where the aerodynamic attachment is installed along the span direction of the blade to the blade root, the installation angle β of the aerodynamic attachment, the width l1 of the aerodynamic attachment, and the length l2 of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge area in the cross section in the chord direction of the blade.

4. The method for designing aerodynamic attachments of a blade according to claim 3, characterized in that: In response to the power generation determined according to the wind speed-power curve being less than the predetermined value or the aerodynamic damping determined according to the wind speed-damping ratio curve having a negative value, the step of adjusting the current design parameters of the aerodynamic attachment comprises: In response to the aerodynamic damping determined according to the wind speed-damping ratio curve having a negative value, adjusting the installation angle β of the aerodynamic attachment so that the aerodynamic damping does not have a negative value; In response to the aerodynamic damping not having a negative value and the power generation determined according to the wind speed-power curve being less than the predetermined value, at least one of the length d of the aerodynamic attachment, the distance L1 from the starting position where the aerodynamic attachment is installed along the span direction of the blade to the blade root, the width l1 of the aerodynamic attachment, and the length l2 of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge area in the cross section in the chordwise direction of the blade is adjusted.

5. The method for designing aerodynamic attachments of a blade according to claim 3, characterized in that: The design method further comprises: initially determining the length d of the pneumatic attachment and the distance L1 from the starting position where the pneumatic attachment is installed along the span direction of the blade to the blade root according to the vibration mode of the blade when the pneumatic attachment is not installed.

6. The method for designing aerodynamic attachments of a blade according to any one of claims 1 to 5, characterized in that: The aerodynamic data includes at least one of a lift coefficient, a drag coefficient, and a pitching moment coefficient.

7. A design device for aerodynamic attachments of a blade, characterized in that: The design device comprises: A design parameter adjustment module to determine the current design parameters of the pneumatic accessories; an aerodynamic data acquisition module, for acquiring aerodynamic data of a blade, wherein the aerodynamic attachment having current design parameters is installed in the trailing edge region of the blade; A curve calculation module calculates the wind speed-power curve and the wind speed-damping ratio curve of the current wind turbine generator set according to the aerodynamic data; The design parameter determination module determines the current design parameters as the final design parameters of the pneumatic accessory in response to the power generation determined according to the wind speed-power curve being greater than or equal to a predetermined value and the aerodynamic damping determined according to the wind speed-damping ratio curve not having a negative value.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions or programs, which, when executed by a processor, cause the processor to execute the design method according to any one of claims 1 to 6.

9. A design device for aerodynamic attachments of a blade, characterized in that: The design device comprises a processor and a memory, wherein the memory stores instructions or programs, and when the instructions or programs are executed by the processor, the processor is prompted to execute the design method according to any one of claims 1 to 6.

10. A blade, characterized in that: An aerodynamic attachment is installed in the trailing edge area of ​​the blade so that the pressure center of the airfoil corresponding to the installation position of the aerodynamic attachment moves toward the leading edge of the blade.

11. The blade according to claim 10, characterized in that The thickness t of the aerodynamic attachment, the chord length c of the blade, the length L of the blade, the distance L1 from the starting position of the aerodynamic attachment to the blade root along the span direction of the blade, the installation angle β of the aerodynamic attachment, the width l1 of the aerodynamic attachment, the length l2 of the curve between the installation position of the aerodynamic attachment and the end of the trailing edge region in the cross section of the chord direction of the blade, and the distance L2 from the end position of the aerodynamic attachment to the blade root along the span direction of the blade meet at least one of the following conditions: l1∈[0.5%×c,5%×c]; l2∈[0,10％×c]； β∈[90°,185°]； t∈[0.1cm,1.5cm].

12. The blade according to claim 10 or 11, characterized in that The aerodynamic attachment is mounted on at least one of the suction surface and the pressure surface of the trailing edge region of the blade, and the aerodynamic attachment includes a plurality of aerodynamic parts spaced apart from each other in a span direction.

13. The blade according to claim 10 or 11, characterized in that The aerodynamic attachment has a chamfer between a mounting surface of the aerodynamic attachment on the blade.

14. The blade according to claim 10 or 11, characterized in that The aerodynamic attachment has a rectangular shape in a cross section along a chordwise direction of the blade.

15. The blade according to claim 10 or 11, characterized in that The material of the pneumatic accessories includes at least one of aluminum alloy, carbon fiber and fiberglass.

16. A wind turbine generator set, characterized in that: Comprising a blade according to any one of claims 10 to 15.

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