Method and device for aerodynamic design of blades of wind generating set

Abstract

The invention discloses a method and device for pneumatic design of a blade of a wind generating set. The method comprises the steps that a blade root coordinate system fixed to the root of the blade and a chord length coordinate system fixed to the pneumatic wing section of the blade are established; wherein the original point of the chord length coordinate system is the front edge of the chord length of the pneumatic airfoil section of the blade; the blade root coordinate system is translated to a coordinate system with the j point as the original point, and a first coordinate system is formed; translating the chord length coordinate system to a coordinate system taking the j point as an original point to form a second coordinate system; wherein the point j is any point on the axis of the blade; at the j point, the first coordinate system is sequentially rotated by a first angle, a second angle and a third angle according to a preset axial rotation sequence, and a second coordinate system is obtained; determining a conversion matrix from the first coordinate system to the second coordinate system; and determining the torque and thrust of a wind wheel of the wind generating set according to the conversion matrix. By adopting the embodiment of the invention, the accuracy of a calculation result can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of wind power generation, and particularly to a method and device for aerodynamic design of wind turbine blades. Background Art

[0002] The aerodynamic shape design of the blades of horizontal axis wind turbines (referred to as wind turbines for short) has been following the aerodynamic shape design method of the wings of fixed-wing aircraft. The key point is that the aerodynamic cross-section of the airfoil of the aircraft is parallel to its forward direction, that is, the normal line of the aerodynamic airfoil cross-section of the blade is perpendicular to the forward direction of the aircraft. Therefore, when designing the aerodynamic shape of the wind turbine blade, the aerodynamic airfoil cross-section of the blade is parallel to the tangent direction of the blade rotation at that location. After selecting the blade airfoil, only the chord length, thickness of the aerodynamic airfoil cross-section of the blade, and the rotation (pre-twist) and translation (pre-bending) of the aerodynamic airfoil cross-section of the blade in the plane are iteratively calculated and determined.

[0003] However, different from aircraft mainly moving in a high-speed straight line, modern wind turbine blades are flexible, slender, and curved structures that rotate in a three-dimensional wind field and can have a length exceeding 100 meters. For the blades designed by this method, the aerodynamic airfoil cross-section is not perpendicular to the axis of the curved blade and is not given. When performing aeroelastic dynamics calculations, an accurate deformation angle cannot be obtained for calculating the aerodynamic force of the wind turbine, and the aerodynamic force can only be applied to the blade structure in a direction perpendicular to the blade axis to calculate the response. That is, the existing design method only calculates the torque and thrust of the wind turbine rotor based on one azimuth angle of the aerodynamic airfoil cross-section of the blade, increasing the uncertainty of the load calculation. Especially for long and flexible blades where bending-torsion coupling and large deformations are becoming increasingly important, this method will lead to distorted calculation results. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a method and device for aerodynamic design of wind turbine blades, which are used to solve the technical problem in the prior art that the torque and thrust of the wind turbine rotor are calculated through one azimuth angle of the aerodynamic airfoil cross-section of the blade, resulting in distorted calculation results.

[0005] In a first aspect, the embodiments of the present application provide a method for aerodynamic design of wind turbine blades, including:

[0006] Establish a root coordinate system fixed at the blade root; wherein, the origin of the root coordinate system is the center of the circle where the blade root is connected to the pitch bearing;

[0007] Establish a chord length coordinate system fixed on the aerodynamic airfoil cross-section of the blade; wherein, the origin of the chord length coordinate system is the leading edge of the chord length of the aerodynamic airfoil cross-section of the blade.

[0008] Translate the root coordinate system of the blade to a coordinate system with point j as the origin to form a first coordinate system; and translate the chord length coordinate system to a coordinate system with point j as the origin to form a second coordinate system; where point j is any point on the blade axis.

[0009] At point j, rotate the first coordinate system by a first angle, a second angle, and a third angle in sequence according to a preset axial rotation order to obtain a second coordinate system; where the first angle is the first azimuth angle, the second angle is the second azimuth angle, and the third angle is the third azimuth angle.

[0010] Determine the transformation matrix from the first coordinate system to the second coordinate system according to the first azimuth angle, the second azimuth angle, and the third azimuth angle.

[0011] Determine the torque and thrust of the wind turbine rotor according to the preset wind speed, tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the blade chord length and thickness, and the transformation matrix, and evaluate the aerodynamic performance of the wind turbine rotor according to the torque and thrust; where the rotor includes multiple blades.

[0012] In a second aspect, an embodiment of the present application provides a device for the aerodynamic design of a wind turbine blade, including:

[0013] A processing module configured to establish a root coordinate system fixed to the blade root; where the origin of the root coordinate system is the center of the circle where the blade root is in contact with the pitch bearing; establish a chord length coordinate system fixed to the blade aerodynamic airfoil section; where the origin of the chord length coordinate system is the leading edge of the chord length of the blade aerodynamic airfoil section; translate the root coordinate system to a coordinate system with point j as the origin to form a first coordinate system; and translate the chord length coordinate system to a coordinate system with point j as the origin to form a second coordinate system; where point j is any point on the blade axis; at point j, rotate the first coordinate system by a first angle, a second angle, and a third angle in sequence according to a preset axial rotation order to obtain a second coordinate system; where the first angle is the first azimuth angle, the second angle is the second azimuth angle, and the third angle is the third azimuth angle; determine the transformation matrix from the first coordinate system to the second coordinate system according to the first azimuth angle, the second azimuth angle, and the third azimuth angle.

[0014] A determination module configured to determine the torque and thrust of the wind turbine rotor according to the preset wind speed, tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the blade chord length and thickness, and the transformation matrix, and evaluate the aerodynamic performance of the wind turbine rotor according to the torque and thrust; where the rotor includes multiple blades.

[0015] In a third aspect, an embodiment of the present application provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the steps of the method according to any one of the above embodiments are implemented.

[0016] In a fourth aspect, an embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The feature is that when the processor executes the computer program, the steps of the method according to any one of the above embodiments are implemented.

[0017] An embodiment of the present application provides a method for the aerodynamic design of a wind turbine blade. By determining three azimuth angles of the aerodynamic airfoil section of the blade, and according to the three azimuth angles, determining the transformation matrix from the first coordinate system to the second coordinate system, and then according to the preset wind speed, tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the transformation matrix, determining the torque and thrust of the wind turbine rotor, and according to the torque and thrust, evaluating the aerodynamic performance of the wind turbine rotor; wherein the rotor includes a plurality of blades. That is, the embodiment of the present application considers the three azimuth angles of the aerodynamic airfoil section of the blade, and determines the torque and thrust of the wind turbine rotor according to these three azimuth angles, improving the accuracy of the calculation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic flowchart of a method for the aerodynamic design of a wind turbine blade provided by an embodiment of the present application;

[0019] Figure 2 It is a schematic structural diagram of a device for the aerodynamic design of a wind turbine blade provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Reference is made herein to the various solutions and features of the present application with reference to the drawings.

[0021] It should be understood that various modifications can be made to the embodiments applied herein. Therefore, the above description should not be regarded as a limitation, but only as an example of the embodiments. Those skilled in the art will think of other modifications within the scope and spirit of the present application.

[0022] The drawings included in the specification and constituting a part of the specification show the embodiments of the present application, and together with the general description of the present application given above and the detailed description of the embodiments given below, are used to explain the principles of the present application.

[0023] These and other features of the present application will become apparent from the following description of the preferred forms of the embodiments given by way of non-limiting examples with reference to the drawings.

[0024] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art can surely implement many other equivalent forms of the present application.

[0025] When combined with the accompanying drawings, the above and other aspects, features, and advantages of the present application will become more apparent in view of the following detailed description.

[0026] Specific embodiments of the present application will be described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments claimed are merely examples of the present application, which can be implemented in various ways. Well-known and / or repetitive functions and structures are not described in detail to avoid obscuring the present application with unnecessary or redundant details. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but are merely used as a basis and representative basis for the claims to teach those skilled in the art to use the present application in substantially any suitable detailed structure in a variety of ways.

[0027] This specification may use the phrases "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments", which may each refer to one or more of the same or different embodiments according to the present application.

[0028] A method for aerodynamic design of wind turbine blades according to an embodiment of the present application. Specifically, this method is applicable to the aerodynamic shape design of large horizontal-axis wind turbine blades. See Figure 1 As shown, a method for aerodynamic design of wind turbine blades provided by an embodiment of the present application includes:

[0029] S100, establishing a root coordinate system fixed at the blade root; wherein, the origin of the root coordinate system is the center of the circle where the blade root is connected to the pitch bearing;

[0030] S200, establishing a chord length coordinate system fixed at the aerodynamic airfoil section of the blade; wherein, the origin of the chord length coordinate system is the leading edge of the chord length of the aerodynamic airfoil section of the blade;

[0031] S300, translating the root coordinate system to a coordinate system with point j as the origin to form a first coordinate system; and translating the chord length coordinate system to a coordinate system with point j as the origin to form a second coordinate system; wherein, point j is an arbitrary point on the blade axis;

[0032] S400, at point j, rotating the first coordinate system successively by a first angle, a second angle, and a third angle in a preset axial rotation sequence to obtain a second coordinate system; wherein, the first angle is the first azimuth angle, the second angle is the second azimuth angle, and the third angle is the third azimuth angle;

[0033] S500. Determine the transformation matrix from the first coordinate system to the second coordinate system according to the first azimuth angle, the second azimuth angle, and the third azimuth angle.

[0034] S600. Determine the torque and thrust of the wind turbine rotor according to the preset wind speed, the tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil profile, the blade chord length and thickness, and the transformation matrix, and evaluate the aerodynamic performance of the wind turbine rotor according to the torque and thrust; wherein the rotor includes multiple blades.

[0035] Specifically, when designing the blade aerodynamically, first define the axis of the blade. The blade axis should be a space curve with continuous third-order derivatives. The angular relationship between the normal of the blade aerodynamic airfoil section at any point along the blade axis and the tangent of the blade axis at that point is given. The most convenient relationship is that the normal and the tangent overlap, that is, the blade aerodynamic airfoil section is perpendicular to the tangent of the blade axis, and the tangent of the blade axis is the normal of the blade aerodynamic airfoil section. In the subsequent iterative process of blade aerodynamic design and structural design, the direction of the aerodynamic force and the influence of blade deformation can be calculated based on this relationship. In this way, the final shape of the blade axis in space and the orientation of the blade aerodynamic airfoil section relative to the blade axis can define the spatial shape of the blade and can be accurately described. The calculation and application of the aerodynamic force can be accurately carried out according to the spatial azimuth angle of the blade aerodynamic airfoil section, eliminating the uncertainty brought by the original method.

[0036] To facilitate the description of this method, it can be assumed that when looking at the wind turbine from upwind, the blade rotates clockwise. First, define a root coordinate system (XYZ) fixed at the blade root. 叶根 . Modern wind turbines all adopt pitch control. The root of the pitch blade is connected to the pitch bearing, and the connection plane is circular. Without loss of generality, define the root coordinate system (XYZ) 叶根 whose origin is at the center of the circle where the blade root is connected to the pitch bearing. The root coordinate system (XYZ) 叶根 has its X-axis and Y-axis in the plane of the root connection circle. The positive direction of the X-axis faces downwind of the wind turbine. The root coordinate system (XYZ) 叶根 has its Z-axis perpendicular to the plane of the root connection circle, and the positive direction of the Z-axis is towards the blade tip. The root coordinate system (XYZ) 叶根 has its Y-axis forming a right-handed rectangular coordinate system with the X-axis and Z-axis.

[0037] A variety of mathematical methods can be used to describe the orientation of a space plane. Optionally, a common method in the wind power industry adopted in this application embodiment is to define a chord length coordinate system (XYZ) fixed on the blade aerodynamic airfoil section 弦长 , and then establish the relationship between this chord length coordinate system (XYZ) 弦长 and the root coordinate system (XYZ) 叶根 to determine the three-dimensional spatial shape of the entire blade.

[0038] Chord length coordinate system (XYZ) of the blade's aerodynamic airfoil section 弦长 The origin is at the leading edge of the chord length of the aerodynamic section. The chord length coordinate system (XYZ) 弦长 The Y-axis of the chord length coordinate system (XYZ) is along the chord line, and the positive direction of the Y-axis points to the trailing edge 弦长 The X-axis of the chord length coordinate system (XYZ) is also in the section plane, and the positive direction of the X-axis faces the low-pressure side of the airfoil 弦长 The Z-axis of the chord length coordinate system (XYZ) forms a right-handed rectangular coordinate system with the X-axis and Y-axis. The positive direction of the Z-axis points to the tip of the blade, and the Z-axis is the normal direction of the blade's aerodynamic airfoil section

[0039] The intersection coordinates of the blade axis and the blade's aerodynamic airfoil section are (x-axis, y-axis, 0) 弦长 This point is in the root coordinate system (XYZ) 叶根 The position in the root coordinate system (XYZ) can be given by the following formula (1) or formula (2). Therefore, after the blade axis is given, as long as the chord length coordinate system (XYZ) of the blade's aerodynamic airfoil section is determined 弦长 In the root coordinate system (XYZ) 叶根 The azimuth angle in the root coordinate system (XYZ), the chord length, and the thickness of the blade's aerodynamic airfoil section determine the aerodynamic shape of the blade. Without loss of generality, denote point j as an arbitrary point on the blade axis, and the blade's aerodynamic airfoil section at point j is the j-section. First, translate the root coordinate system (XYZ) 叶根 to the first coordinate system (XYZ) with point j as the origin j0 whose (XY) j0 plane is parallel to the root circle plane. Then, translate the chord length coordinate system (XYZ) 弦长 to the second coordinate system (XYZ) with point j as the origin j3 whose (XY) j3 plane is the same plane as the (XY) 弦长 plane and the j-section. That is, the first coordinate system (XYZ) j0 has the same direction as the root coordinate system (XYZ) 叶根 but different origins. The second coordinate system (XYZ) j3 has the same direction as the chord length coordinate system (XYZ) 弦长 but different origins. As long as the azimuth angle relationship between the second coordinate system (XYZ) j3 and the first coordinate system (XYZ) j0 is determined. The unit vector along the Z j3 axis is the unit normal vector of the blade's j-section. Therefore, as long as the direction cosines of the unit vector of the Z j3 axis in the (XYZ) j0 coordinate system, and the rotation angle of the j-section around the Z j3 axis are determined, the second coordinate system (XYZ) j3With the first coordinate system (XYZ) j0 Coordinate system azimuth relationship.

[0040] Then, at point j, rotate the first coordinate system successively by a first angle, a second angle, and a third angle according to a preset axial rotation sequence to obtain a second coordinate system. Specifically, in some embodiments, three rotation angles can be selected to describe the rotation relationship from the first coordinate system (XYZ) j0 to the second coordinate system (XYZ) j3 First, let the first coordinate system (XYZ) j0 rotate around the negative X j0 axis by the first angle α j to obtain a new coordinate system (XYZ) j1 with the same origin, and the X j1 axis is the same as the X j0 axis. The Y j1 and Z j1 axes, and the Y j0 and Z j0 axes all differ by -α j angle. Then, let the coordinate system (XYZ) j1 rotate around the negative Y j1 axis by the second angle β j to obtain a new coordinate system (XYZ) j2 with the Y j2 axis the same as the Y j1 axis. The X j2 and Z j2 axes, and the X j1 and Z j1 axes all differ by -β j angle. Finally, let the coordinate system (XYZ) j2 rotate around the negative Z j2 axis by the third angle θ j to obtain the second coordinate system (XYZ) j3 with the Z j3 axis the same as the Z j2 axis. The X j3 and Y j3 axes, and the X j2 and Y j2 axes differ by -θ j angle. The (XY) j3 plane is the j-section of the blade at point j. In other embodiments, the orientation of the j-section can also be defined according to other axial rotation sequences. For example, rotate around Y j0 first and then around X j1 . The mathematical expressions will be different, but the final spatial orientation of the blade aerodynamic airfoil section and the aerodynamic shape of the blade are the same. This application does not limit which axial order to rotate. Among them, the first angle α jis the first azimuth angle, and the second angle β j is the second azimuth angle, and the third angle θ j is the third azimuth angle.

[0041] Then, according to the first azimuth angle, the second azimuth angle, and the third azimuth angle, determine the transformation matrix from the first coordinate system to the second coordinate system; according to the preset wind speed, the tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the blade chord length and thickness, and the transformation matrix, determine the torque and thrust of the wind turbine rotor, and evaluate the aerodynamic performance of the wind turbine rotor according to the torque and thrust; wherein the rotor includes a plurality of blades.

[0042] The embodiment of the present application provides a method for the aerodynamic design of a wind turbine blade. By determining three azimuth angles of the blade aerodynamic airfoil section, and according to the three azimuth angles, determining the transformation matrix from the first coordinate system to the second coordinate system, and then according to the preset wind speed, the tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the blade chord length and thickness, and the transformation matrix, determine the torque and thrust of the wind turbine rotor, and evaluate the aerodynamic performance of the wind turbine rotor according to the torque and thrust; wherein the rotor includes a plurality of blades. That is, the embodiment of the present application considers three azimuth angles of the blade aerodynamic airfoil section, and determines the torque and thrust of the wind turbine rotor according to these three azimuth angles, improving the accuracy of the calculation results.

[0043] In some embodiments, the process of determining the first azimuth angle and the second azimuth angle includes:

[0044] According to the preset function of the blade axis, determine the unit tangent vector of the blade axis;

[0045] According to the unit tangent vector, determine the first azimuth angle and the second azimuth angle of the blade aerodynamic airfoil section.

[0046] Specifically, the process of determining the unit tangent vector of the blade axis according to the preset function of the blade axis is as follows:

[0047] The preset function of the blade axis can have different expression forms. For example, the preset function of the blade axis can be expressed according to the following formula (1) or formula (2).

[0048] In the root coordinate system of the blade, the preset axis function of the blade can be expressed as a formula of a space curve:

[0049]

[0050] Alternatively, in the form of a parametric equation with the arc length s along the blade axis, the preset function of the blade axis is:

[0051]

[0052] Among them, in Formula (1), the starting point of the z - coordinate of the blade axis is at the center of the root circle of the blade, that is, the origin of the root coordinate system (XYZ) 叶根 of the root coordinate system (XYZ) 叶根 The origin of the root coordinate system (XYZ) can be at the center of the circle where the root of the blade is connected to the pitch bearing. z L is the length of the blade along the z - axis of the root coordinate system starting from the origin of the root coordinate system. (x, y, z) are the spatial coordinates on the blade axis corresponding to the z - coordinate in the root coordinate system. Formula (1) uses the z - coordinate as the independent variable, and x and y as the dependent variables, so functions of x and y need to be given.

[0053] In Formula (2), the starting point of the arc length of the blade axis is at the center of the root circle of the blade, that is, the origin of the root coordinate system (XYZ) 叶根 of the root coordinate system (XYZ) 叶根 The origin of the root coordinate system (XYZ) can be at the center of the circle where the root of the blade is connected to the pitch bearing. L s is the length of the blade along the axis. (x, y, z) are the spatial coordinates on the blade axis corresponding to the arc length s in the root coordinate system. Formula (2) uses the arc length s as the independent variable, and x, y, and z as the dependent variables, so functions of x, y, and z need to be given. (x L , y L , z L ) are the spatial coordinates corresponding to L s . The selected f(z), g(z) or f x (s), f y (s) and f z (s) are functions with continuous third - order derivatives, and the tangent and spatial curvature of the blade axis vary smoothly and continuously along the blade axis. In numerical calculations, they can be generated by numerical methods such as polynomial fitting.

[0054] Next, based on Formula (1) and Formula (2), the preset blade axis is expressed by the position vector as follows in Formula (3):

[0055] r(z) = f(z)i + g(z)m + zk

[0056] r(s) = f x (s)i + f y (s)m + f z (s)k Formula (3)

[0057] Among them, i, m, and k are the basis vectors of the root coordinate system. The position vector r points from the origin of the root coordinate system to an arbitrary point on the blade axis. The tangent vector on the blade axis can be expressed as follows in Formula (4):

[0058] r′(z) = f′(z)i + g′(z)m + k

[0059] r′(s) = f x ′(s)i + f y ′(s)m + f z ′(s)k Equation (4)

[0060] where r′(z) is the derivative of r(z), f′(z) is the derivative of f(z), g′(z) is the derivative of g(z), r′(s) is the derivative of r(s), f x ′(s) is the derivative of f x (s), f y ′(s) is the derivative of f y (s), f z ′(s) is the derivative of f z (s).

[0061] Any point on the blade axis is denoted as point j. z j and s j are the corresponding Z - axis coordinate and arc length. The unit tangent vector t of the blade axis at this point j j can be calculated from the above formula as follows, Equations (5) and (6):

[0062]

[0063] According to the coordinate rotation transformation relationship of the three - dimensional rectangular coordinate system in space, the coordinate transformation between the second coordinate system (XYZ) j3 and the first coordinate system (XYZ) j0 can be expressed as follows, Equation (7):

[0064]

[0065] where and are the coordinates of a spatial point j in the first coordinate system (XYZ) j0 and the second coordinate system (XYZ) j3 respectively. The [T] matrix is the coordinate transformation matrix from the first coordinate system (XYZ) j0 to the second coordinate system (XYZ) j3 , that is, [T] is the transformation matrix in this application, and can also be called the projection matrix. [T] T is the transpose matrix of the transformation matrix [T]. The unit normal vector of the j - section is The unit normal vector n of the j - section of the blade can be obtained from Equation (7) j in the first coordinate system (XYZ) j0 and the root coordinate system (XYZ) 叶根 and is expressed as follows, Equation (9):

[0066] n j = -sinβ j i + cosβ j sinα j m + cosβ j cosα j k formula (9)

[0067] The unit normal vector of the j - section of the blade only contains the first angle α j and the second angle β j These two angles are related to the selected rotation sequence. If the rotation about the Z - axis is done first, it will increase the complexity of formula (9).

[0068] The following details the determination process of the first azimuth angle (the first angle α j ) and the second azimuth angle (the second angle β j ).

[0069] Continuing with the above example, in some embodiments, according to the unit tangent vector, the first azimuth angle and the second azimuth angle of the blade aerodynamic airfoil section are determined, including:

[0070] According to the unit tangent vector and the first component, the second component and the third component in the preset root coordinate system of the blade, determine the unit normal vector of the blade aerodynamic airfoil section;

[0071] According to the unit normal vector and the relationship between the unit normal vector and the first azimuth angle and the second azimuth angle of the blade aerodynamic airfoil section, determine the first azimuth angle and the second azimuth angle of the blade aerodynamic airfoil section.

[0072] In some embodiments, according to the unit tangent vector and the first component, the second component and the third component in the preset root coordinate system of the blade, determining the unit normal vector of the blade aerodynamic airfoil section includes:

[0073] Determine the difference vector according to the first component, the second component and the third component in the preset root coordinate system of the blade;

[0074] Determine the unit normal vector of the blade aerodynamic airfoil section according to the difference vector and the unit tangent vector.

[0075] Specifically, first define the relationship between the unit normal vector n j of the blade aerodynamic airfoil section and the unit tangent vector t j of the blade axis, which is used to calculate the torque and thrust of the wind turbine rotor.

[0076] The relationship between the unit normal vector n j of the blade aerodynamic airfoil section and the unit tangent vector t j of the blade axis can be represented by the difference vector c jis expressed as the following formula (10):

[0077] c j = t j - n j = c x (z j )i + c y (z j )m + c z (z j )k Formula (10)

[0078] wherein, in formula (10), c x (z j ), c y (z j ) and c z (z j ) are the components of c j in the blade root coordinate system. Combining formulas (5) and (9), the first component c x (z j ), the second component c y (z j ) and the third component c z (z j ) in the blade root coordinates are obtained as the following formula (11):

[0079]

[0080] Formulas (10) and (11) give the expression of the relationship between the unit normal vector n j of the blade aerodynamic airfoil section and the unit tangent vector t j of the blade axis. c x (z j ), c y (z j ) and c z (z j ) can be determined according to the design optimization index for design. For example, referring to the average deformation angle of the blade during large deformation, etc. n j , t j and c j form an equilateral triangle with t j and n j as the waists. The angle between n j and t j can be restricted to not be greater than a given angle δ j . Then, when selecting c x (z j ), c y (z j ) and c z (z j) When the following conditions are met, the formula (12) must be satisfied:

[0081]

[0082] When performing iterative design calculations, the first azimuth angle α can be estimated from formula (11) first j and the second azimuth angle β j , as obtained from formula (13):

[0083]

[0084] where f′(z j ) is the derivative of f(z) at point j, and g′(z j ) is the derivative of g(z) at point j.

[0085] When the unit normal vector n of the blade aerodynamic airfoil section j overlaps with the unit tangent vector t of the blade axis j , c j (z j ) = 0, z j ∈[0, z L , that is, as formula (14):

[0086] c x (z j ) = c y (z j ) = c z (z j ) = 0, z j ∈[0, z L Formula (14)

[0087] That is, the preset first component c x (z j ), the second component c y (z j ), and the third component c z (z j ) are all 0. When the first component c x (z j ), the second component c y (z j ), and the third component c z (z j ) are all 0, the obtained first azimuth angle α j and the second azimuth angle β j are changed to formula (15) through formula (13), as follows:

[0088]

[0089] Then, set the third angle θj , generally, the third angle θ j represents the pre-twist angle of the blade aerodynamic section, which needs to be determined together with the chord length and thickness during the aerodynamic iterative calculation. Therefore, it is most convenient to place it at the end. That is to say, the third angle θ j can be obtained through existing iterative calculation methods, which will not be elaborated in this application. In the existing design methods, only based on one azimuth angle of the blade aerodynamic airfoil section (i.e., the third angle θ j ), calculating the torque and thrust of the wind turbine rotor will lead to the problem of distorted calculation results.

[0090] However, in this application, through three azimuth angles, namely the first angle α j , the second angle β j and the third angle θ j , calculating the torque and thrust of the wind turbine rotor improves the accuracy of the calculation results. Among them, the third azimuth angle (i.e., the third angle θ j ) is obtained through existing methods, and this application will not elaborate.

[0091] After calculating the transformation matrix [T] according to formula (8), the subsequent aerodynamic iterative calculation can be carried out.

[0092] As can be seen from the above description, under the condition of satisfying formula (12), the first component c x (z j ), the second component c y (z j ) and the third component c z (z j ) in the preset root coordinate system.

[0093] Then, according to the first component c x (z j ), the second component c y (z j ) and the third component c z (z j ), using the above formula (10), determine the difference vector c j .

[0094] Then, according to the difference vector c j and the unit tangent vector t j , using the above formula (10), determine the unit normal vector n j of the blade aerodynamic airfoil section.

[0095] Then, according to the unit normal vector n j , and the unit normal vector n jThe relationship with the first azimuth angle and the second azimuth angle of the blade aerodynamic airfoil section, that is, using formula (9) and combining with the above formula (5), formula (11) can be obtained. According to formula (11), formula (13) can be obtained, and then the first azimuth angle α of the blade aerodynamic airfoil section can be obtained. j and the second azimuth angle β j .

[0096] Then, the third azimuth angle θ is obtained according to the existing calculation method. j .

[0097] Then, according to the first azimuth angle α j , the second azimuth angle β j and the third azimuth angle θ j , the transformation matrix [T] from the first coordinate system to the second coordinate system is determined using formula (8).

[0098] Through the above description, the characteristics of this design method can be seen as follows:

[0099] (1) The first azimuth angle α j and the second azimuth angle β j of the blade aerodynamic airfoil section are completely determined by the unit tangent of the blade axis. The third azimuth angle θ j is determined by the existing aerodynamic iterative calculation.

[0100] (2) The blade aerodynamic airfoil section is perpendicular to the axis of the blade, and the aerodynamic force system can be directly applied to the beam element model established according to the blade axis.

[0101] (3) When considering the influence of large blade deformation, the deformed blade aerodynamic airfoil section should still be perpendicular to the axis (tangent) of the beam element. This brings convenience to the calculation considering the influence of large blade deformation.

[0102] (4) When calculating the load considering the influence of large deformation of long and flexible blades, the deformed blade axis can be calculated first, and the corresponding first azimuth angle α j and the second azimuth angle β j can be obtained. Then, the torsional angle of the large deformation of the blade is added to the third azimuth angle θ j , and the influence of the bending and torsion deformation of the blade on the azimuth change of the blade aerodynamic airfoil section can be accurately described.

[0103] In some embodiments, according to the preset wind speed, tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the transformation matrix, the torque and thrust of the wind turbine rotor are determined, including:

[0104] Determine the wind speed relative to the blade aerodynamic airfoil section at the preset wind speed in the second coordinate system according to the preset wind speed and the transformation matrix;

[0105] Determine the torque and thrust of the wind turbine rotor based on the preset wind speed in the second coordinate system relative to the wind speed of the blade airfoil section, the preset tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the transformation matrix.

[0106] In some embodiments, determining the wind speed in the second coordinate system relative to the wind speed of the blade airfoil section based on the preset wind speed and the transformation matrix includes:

[0107] Determine the wind speed in the root coordinate system relative to the wind speed of the blade airfoil section based on the preset wind speed;

[0108] Perform coordinate transformation through the transformation matrix based on the wind speed in the root coordinate system relative to the wind speed of the blade airfoil section to obtain the wind speed in the second coordinate system relative to the wind speed of the blade airfoil section.

[0109] In some embodiments, determining the torque and thrust of the wind turbine rotor based on the wind speed in the second coordinate system relative to the wind speed of the blade airfoil section, the preset tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the transformation matrix includes:

[0110] Determine the induction factor based on the wind speed in the second coordinate system relative to the wind speed of the blade airfoil section, the preset tip speed ratio and pitch angle of the wind turbine;

[0111] Determine the actual wind speed and aerodynamic force components of the blade airfoil section based on the induction factor, the preset shape function of the blade airfoil, the chord length and thickness of the blade;

[0112] Perform coordinate transformation through the transpose matrix of the transformation matrix, and accumulate the aerodynamic force components of the blade airfoil section after transforming to the root coordinate system to obtain the torque and thrust of the wind turbine rotor.

[0113] The following details the process of obtaining the torque and thrust of the wind turbine rotor after determining the transformation matrix [T] from the first coordinate system to the second coordinate system, and evaluating the aerodynamic performance of the wind turbine rotor based on the torque and thrust.

[0114] First, determine the wind speed in the root coordinate system relative to the wind speed of the blade airfoil section based on the preset wind speed, that is, determine the wind speed in the first coordinate system relative to the wind speed of the blade airfoil section. The root coordinate system has the same direction as the first coordinate system but different origins.

[0115] Then, according to the preset wind speed relative to the blade airfoil section, coordinate system transformation is performed through the transformation matrix [T] to obtain the wind speed relative to the blade airfoil section in the second coordinate system under the preset wind speed.

[0116] Then, according to the wind speed relative to the blade airfoil section in the second coordinate system, the preset tip speed ratio and pitch angle of the wind turbine, the induction factor is determined; according to the induction factor, as well as the shape function of the preset blade airfoil, the chord length and thickness of the blade, the actual wind speed and aerodynamic force components at the blade airfoil section are determined.

[0117] Then, through the transpose matrix [T] of the transformation matrix T coordinate system transformation is performed to accumulate the aerodynamic force components of each point at the blade airfoil section after transforming them to the hub coordinate system, obtaining the torque and thrust of the wind turbine rotor, and according to the torque and thrust, the aerodynamic performance of the wind turbine rotor is evaluated; wherein the rotor includes a plurality of blades. Optionally, the rotor may include three blades.

[0118] If the aerodynamic performance of the wind turbine rotor does not meet the preset conditions, then return to the previous steps, readjust the preset parameters, and recalculate, that is, perform aerodynamic iterative calculation. For example, if the aerodynamic performance of the wind turbine rotor does not meet the preset conditions, if the blade axis is inappropriate, then it can return to the function of resetting the blade axis in the previous steps, that is, reset the blade axis. If the chord length of the blade is inappropriate, then it can return to the previous steps to reset the chord length of the blade, etc., until the aerodynamic performance of the wind turbine rotor meets the preset conditions.

[0119] If the aerodynamic performance of the wind turbine rotor meets the preset conditions, it is determined that the aerodynamic design of the wind turbine blade is completed.

[0120] Based on the same inventive concept, as shown in Figure 2 this application embodiment provides a device for the aerodynamic design of a wind turbine blade, including:

[0121] The processing module 100 is configured to establish a root coordinate system fixed at the blade root; wherein, the origin of the root coordinate system is the center of the circle where the blade root is connected to the pitch bearing; establish a chord length coordinate system fixed on the aerodynamic airfoil section of the blade; wherein, the origin of the chord length coordinate system is the leading edge of the chord length of the aerodynamic airfoil section of the blade; translate the root coordinate system to a coordinate system with point j as the origin to form a first coordinate system; and translate the chord length coordinate system to a coordinate system with point j as the origin to form a second coordinate system; wherein, point j is any point on the blade axis; at point j, rotate the first coordinate system in a preset axial rotation sequence by a first angle, a second angle, and a third angle to obtain the second coordinate system; wherein, the first angle is the first azimuth angle, the second angle is the second azimuth angle, and the third angle is the third azimuth angle; determine the transformation matrix from the first coordinate system to the second coordinate system according to the first azimuth angle, the second azimuth angle, and the third azimuth angle.

[0122] The determination module 200 is configured to determine the torque and thrust of the wind turbine of the wind power generation unit according to the preset wind speed, the tip speed ratio and the pitch angle of the wind power generation unit, the shape function of the blade airfoil, the blade chord length and thickness, and the transformation matrix, and evaluate the aerodynamic performance of the wind turbine of the wind power generation unit according to the torque and thrust; wherein the wind turbine includes a plurality of blades.

[0123] Based on the same inventive concept, an embodiment of the present application provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the steps of the method described in any of the above embodiments are implemented.

[0124] Based on the same inventive concept, an embodiment of the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The characteristic is that when the processor executes the computer program, the steps of the method described in any of the above embodiments are implemented.

[0125] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A method for the aerodynamic design of wind turbine blades, characterized in that, Including: Establishing a root coordinate system fixed at the blade root; wherein, the origin of the root coordinate system is the center of the circle where the blade root is connected to the pitch bearing; Establishing a chord length coordinate system fixed on the aerodynamic airfoil section of the blade; wherein, the origin of the chord length coordinate system is the leading edge of the chord length of the aerodynamic airfoil section of the blade; Translating the root coordinate system to a coordinate system with point j as the origin to form a first coordinate system; and translating the chord length coordinate system to a coordinate system with point j as the origin to form a second coordinate system; wherein, point j is any point on the blade axis; At point j, rotating the first coordinate system by a first angle, a second angle, and a third angle in sequence according to a preset axial rotation order to obtain the second coordinate system; wherein, the first angle is the first azimuth angle, the second angle is the second azimuth angle, and the third angle is the third azimuth angle; Determining a transformation matrix from the first coordinate system to the second coordinate system according to the first azimuth angle, the second azimuth angle, and the third azimuth angle; Determining the torque and thrust of the wind turbine rotor according to a preset wind speed, the tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the transformation matrix, and evaluating the aerodynamic performance of the wind turbine rotor according to the torque and thrust; wherein the rotor includes a plurality of blades.

2. The method according to claim 1, wherein The determination process of the first azimuth angle and the second azimuth angle includes: Determining the unit tangent vector of the blade axis according to a preset function of the blade axis; Determining the first azimuth angle and the second azimuth angle of the aerodynamic airfoil section of the blade according to the unit tangent vector.

3. The method according to claim 2, wherein Determining the first azimuth angle and the second azimuth angle of the aerodynamic airfoil section of the blade according to the unit tangent vector includes: Determining the unit normal vector of the aerodynamic airfoil section of the blade according to the unit tangent vector and the first component, second component, and third component in the preset root coordinate system; Determining the first azimuth angle and the second azimuth angle of the aerodynamic airfoil section of the blade according to the unit normal vector and the relationship between the unit normal vector and the first azimuth angle and the second azimuth angle of the aerodynamic airfoil section of the blade.

4. The method according to claim 3, wherein Determining the unit normal vector of the aerodynamic airfoil section of the blade according to the unit tangent vector and the first component, second component, and third component in the preset root coordinate system includes: Determining a difference vector according to the first component, second component, and third component in the preset root coordinate system; Determining the unit normal vector of the aerodynamic airfoil section of the blade according to the difference vector and the unit tangent vector.

5. The method according to claim 1, characterized in that Determining the torque and thrust of the wind turbine rotor according to a preset wind speed, the tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the transformation matrix includes: Determining the wind speed relative to the aerodynamic airfoil section of the blade of a preset wind speed in the second coordinate system according to the preset wind speed and the transformation matrix; Determine the torque and thrust of the wind turbine rotor according to the preset wind speed relative to the airfoil section of the blade in the second coordinate system, the preset tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the conversion matrix.

6. The method according to claim 5, wherein Determine the preset wind speed relative to the airfoil section of the blade in the second coordinate system according to the preset wind speed and the conversion matrix, including: Determine the preset wind speed relative to the airfoil section of the blade in the root coordinate system according to the preset wind speed; Perform coordinate transformation through the conversion matrix according to the preset wind speed relative to the airfoil section of the blade to obtain the preset wind speed relative to the airfoil section of the blade in the second coordinate system.

7. The method according to claim 5, wherein Determine the torque and thrust of the wind turbine rotor according to the preset wind speed relative to the airfoil section of the blade in the second coordinate system, the preset tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the chord length and thickness of the blade, and the conversion matrix, including: Determine the induction factor according to the preset wind speed relative to the airfoil section of the blade in the second coordinate system, the preset tip speed ratio and pitch angle of the wind turbine; Determine the actual wind speed and aerodynamic force components of the blade airfoil section according to the induction factor, the preset shape function of the blade airfoil, the chord length and thickness of the blade; Perform coordinate transformation through the transpose matrix of the conversion matrix, and accumulate the aerodynamic force components of the blade airfoil section after transforming them to the root coordinate system to obtain the torque and thrust of the wind turbine rotor.

8. A device for the aerodynamic design of wind turbine blades, characterized in that, Including: A processing module configured to establish a root coordinate system fixed at the blade root; wherein, the origin of the root coordinate system is the center of the circle where the blade root is connected to the pitch bearing; establish a chord length coordinate system fixed on the blade airfoil section; wherein, the origin of the chord length coordinate system is the leading edge of the chord length of the blade airfoil section; translate the root coordinate system to a coordinate system with point j as the origin to form a first coordinate system; and translate the chord length coordinate system to a coordinate system with point j as the origin to form a second coordinate system; wherein, point j is an arbitrary point on the blade axis; at point j, rotate the first coordinate system in a preset axial rotation sequence by a first angle, a second angle, and a third angle to obtain the second coordinate system; wherein, the first angle is the first azimuth angle, the second angle is the second azimuth angle, and the third angle is the third azimuth angle; determine the conversion matrix from the first coordinate system to the second coordinate system according to the first azimuth angle, the second azimuth angle, and the third azimuth angle; A determination module configured to determine the torque and thrust of the wind turbine rotor according to the preset wind speed, the tip speed ratio and pitch angle of the wind turbine, the shape function of the blade airfoil, the blade chord length and thickness, and the conversion matrix, and evaluate the aerodynamic performance of the wind turbine rotor according to the torque and thrust; wherein the rotor includes multiple blades.

9. A computer-readable storage medium, characterized in that, Computer program instructions are stored on the computer-readable storage medium, and when the computer program instructions are executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

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