Wind turbine blade aeroelasticity analysis method, system, equipment and medium

Abstract

The invention relates to the technical field of wind power generation, particularly provides a wind turbine blade aeroelasticity analysis method, system and equipment and a medium, and aims to solve the problem of aeroelasticity analysis of wind turbine blades. Therefore, the aeroelasticity analysis method for the wind turbine blade comprises the steps that the aerodynamic load of the blade is determined based on a pre-constructed aerodynamic model, and the aerodynamic model is constructed based on a vortex wake method of a lift line; based on a pre-constructed blade structure model and the aerodynamic load of the blade, determining structure response information of the blade; and analyzing the aeroelasticity of the blade based on the aerodynamic load and the structural response information of the blade. According to the method, the complex interaction between the unsteady aerodynamic load and the elastic deformation of the blade can be predicted, so that the influence of the aeroelastic effect on the power generation performance and fatigue life of the wind turbine is understood, and a reference is provided for reasonable design of the wind turbine blade.

Description

Technical Field

[0001] The present application relates to the technical field of wind power generation, and in particular to a method, system, electronic device and storage medium for analyzing aeroelasticity of wind turbine blades. Background Art

[0002] With the continuous advancement of technology and the pursuit of energy efficiency, the size of wind turbines has gradually increased, and the blades have become more slender. This design change is intended to capture more energy from the wind, thereby reducing the cost of wind power generation. However, this change has also brought a series of new challenges, especially the aeroelastic problem caused by the increased structural flexibility of the blades. The aeroelastic effect not only affects the overall performance and stability of the wind turbine, but also has a significant impact on the operating life of the wind turbine. Therefore, the aeroelastic problem of wind turbine blades has become one of the key issues that must be considered when designing wind turbine blades.

[0003] Accordingly, the art needs a new aeroelastic analysis solution for wind turbine blades to solve the above problems. Summary of the invention

[0004] In order to overcome the above-mentioned defects, the present application is proposed to solve or at least partially solve the aeroelastic analysis problem for wind turbine blades.

[0005] In a first aspect, a method for aeroelastic analysis of a wind turbine blade is provided, the method comprising: determining the aerodynamic load of the blade based on a pre-constructed aerodynamic model, wherein the aerodynamic model is constructed based on a vortex wake method of lift lines; determining structural response information of the blade based on a pre-constructed blade structural model and the aerodynamic load of the blade; and analyzing the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade.

[0006] In a technical solution of the above-mentioned aeroelastic analysis method for wind turbine blades, the aerodynamic load of the blade is determined based on a pre-constructed aerodynamic model, including: obtaining Fourier series expansion coefficients; determining the induced velocity of the attached vortex based on the Fourier series expansion coefficients; and determining the aerodynamic load of the blade based on the induced velocity of the attached vortex.

[0007] In a technical solution of the above-mentioned aeroelastic analysis method for wind turbine blades, the obtaining of Fourier series expansion coefficients includes: obtaining wind speed information, blade parameters, wind rotor information and arbitrary position information; determining an induced velocity calculation formula for an attached vortex based on the wind speed information, the blade parameters, the wind rotor information and the arbitrary position information; determining an induced angle of attack based on the induced velocity calculation formula for the attached vortex and the wind speed information; determining a geometric angle of attack based on the wind speed information, the blade parameters and the wind rotor information; determining an effective angle of attack based on the induced angle of attack, the geometric angle of attack, and the corresponding relationship between the induced angle of attack, the geometric angle of attack and the effective angle of attack; determining a lift coefficient based on the induced velocity calculation formula for the attached vortex; and determining Fourier series expansion coefficients based on the effective angle of attack and the lift coefficient.

[0008] In a technical solution of the above-mentioned aeroelastic analysis method for wind turbine blades, determining the induced velocity of the attached vortex based on the Fourier series expansion coefficient includes: determining the initial circulation of the attached vortex based on the Fourier series expansion coefficient; updating the effective angle of attack based on the initial circulation of the attached vortex; updating the Fourier series expansion coefficient based on the initial circulation of the attached vortex and the updated effective angle of attack; updating the initial circulation of the attached vortex based on the updated Fourier series expansion coefficient; determining the induced velocity of the attached vortex based on the updated initial circulation of the attached vortex and the calculation formula of the induced velocity of the attached vortex.

[0009] In a technical solution of the above-mentioned aeroelastic analysis method for wind turbine blades, the aerodynamic load of the blade is determined based on the induced velocity of the attached vortex, including: iteratively calculating the effective angle of attack and the induced angle of attack based on the induced velocity of the attached vortex until the effective angle of attack and the induced angle of attack meet preset accuracy requirements; determining the final lift coefficient and the drag coefficient based on the effective angle of attack and the induced angle of attack that meet the preset accuracy requirements; determining the aerodynamic load of the blade based on the final lift coefficient and the drag coefficient, the aerodynamic load including axial thrust, torque and power.

[0010] In a technical solution of the above-mentioned wind turbine blade aeroelastic analysis method, the structural response information of the blade is determined based on a pre-constructed blade structure model and the aerodynamic load of the blade, including: taking the aerodynamic load of the blade as the input of the blade structure model, and determining the structural response information of the blade under the action of the aerodynamic load, wherein the blade structure model is constructed based on geometrically precise beam theory.

[0011] In a technical solution of the above-mentioned wind turbine blade aeroelastic analysis method, the aerodynamic elasticity of the blade is analyzed based on the aerodynamic load and structural response information of the blade, including: iteratively calculating the aerodynamic load and structural response information of the blade based on the aerodynamic model, the blade structural model, the structural response information of the blade and the aerodynamic load until the aerodynamic load and structural response information of the blade meet the preset convergence conditions; and analyzing the aerodynamic elasticity of the blade based on the aerodynamic load and structural response information of the blade that meet the preset convergence conditions.

[0012] In a second aspect, a wind turbine blade aeroelastic analysis system is provided, the system comprising: an aerodynamic load determination module, for determining the aerodynamic load of the blade based on a pre-constructed aerodynamic model, wherein the aerodynamic model is constructed based on a vortex wake method of lift lines; a structural response information determination module, for determining the structural response information of the blade based on a pre-constructed blade structural model and the aerodynamic load of the blade; and an analysis module, for analyzing the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade.

[0013] In a third aspect, an electronic device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method described in any one of the technical solutions of the above-mentioned wind turbine blade aeroelastic analysis method is implemented.

[0014] In a fourth aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, wherein the program codes are suitable for being loaded and run by a processor to execute the method described in any one of the technical solutions of the above-mentioned wind turbine blade aeroelastic analysis method.

[0015] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0016] The aeroelastic analysis method for wind turbine blades provided in the present application includes: determining the aerodynamic load of the blade based on a pre-constructed aerodynamic model, wherein the aerodynamic model is constructed based on the vortex wake method of lift lines; determining the structural response information of the blade based on the pre-constructed blade structure model and the aerodynamic load of the blade; and analyzing the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade. The present application constructs an aerodynamic model based on the vortex wake method of lift lines, and determines the aerodynamic load of the blade based on the aerodynamic model; then, in combination with the blade structure model and the aerodynamic load, the structural response information of the blade can be determined, and then the elastic deformation of the blade caused by the non-steady-state aerodynamic load and its interaction can be predicted. It can provide an in-depth understanding of the influence of the aeroelastic effect on the power generation performance and fatigue life of the wind turbine, and provide a reference for the reasonable design of wind turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The disclosure of the present application will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0018] Figure 1 is a schematic flow chart of the main steps of a method for analyzing aeroelasticity of a wind turbine blade according to an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of lift lines according to an embodiment of the present application;

[0020] Figure 3 is a schematic diagram of a rigid tail vortex and its coordinate system according to an embodiment of the present application;

[0021] Figure 4 is a schematic diagram of a beam deformation state according to an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of a prediction and correction data exchange method for coupling an aerodynamic model and a blade structure model according to an embodiment of the present application;

[0023] Figure 6 is a schematic diagram of the main structure of a wind turbine blade aeroelasticity analysis system according to an embodiment of the present application;

[0024] Figure 7 It is a schematic diagram of the main structure of an electronic device according to an embodiment of the present application.

[0025] Reference numerals:

[0026] 11: memory; 12: processor; 61: aerodynamic load determination module; 62: structural response information determination module; 63: analysis module. DETAILED DESCRIPTION

[0027] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0028] In the description of the present application, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, memory, and may also include software parts, such as program code, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware or a combination of the two. Computer-readable storage media include any suitable medium that can store program code, such as a disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B" and may include only A, only B or A and B. The singular terms "one" and "the" may also include plural forms.

[0029] With the continuous advancement of technology and the pursuit of energy efficiency, the size of wind turbines has gradually increased, and the blades have become more slender. This design change is intended to capture more energy from the wind, thereby reducing the cost of wind power generation. However, this change has also brought a series of new challenges, especially the aeroelastic problem caused by the increased structural flexibility of the blades. The aeroelastic effect not only affects the overall performance and stability of the wind turbine, but also has a significant impact on the operating life of the wind turbine. Therefore, the aeroelastic problem of wind turbine blades has become one of the key issues that must be considered when designing wind turbine blades.

[0030] The aeroelastic analysis method for wind turbine blades provided in the present application includes: determining the aerodynamic load of the blade based on a pre-constructed aerodynamic model, wherein the aerodynamic model is constructed based on the vortex wake method of lift lines; determining the structural response information of the blade based on the pre-constructed blade structure model and the aerodynamic load of the blade; and analyzing the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade. The present application constructs an aerodynamic model based on the vortex wake method of lift lines, and determines the aerodynamic load of the blade based on the aerodynamic model; then, in combination with the blade structure model and the aerodynamic load, the structural response information of the blade can be determined, and then the elastic deformation of the blade caused by the non-steady-state aerodynamic load and its interaction can be predicted. It can provide an in-depth understanding of the influence of the aeroelastic effect on the power generation performance and fatigue life of the wind turbine, and provide a reference for the reasonable design of wind turbine blades.

[0031] See attached Figure 1 , Figure 1 FIG. 1 is a schematic flow chart of the main steps of a method for analyzing aeroelasticity of wind turbine blades according to an embodiment of the present application. Figure 1 As shown, the wind turbine blade aeroelastic analysis method in the embodiment of the present application mainly includes the following steps S101 to S103.

[0032] Step S101: determining the aerodynamic load of the blade based on a pre-constructed aerodynamic model, wherein the aerodynamic model is constructed based on a vortex wake method of lift lines.

[0033] In this embodiment, the aerodynamic model is constructed using the vortex wake method based on lift lines, taking into account the three-dimensional flow of the wind turbine blade flow field, and can accurately simulate the aerodynamic performance of large wind turbine blades. The vortex wake method can handle unsteady flow problems. The vortex wake method assumes that the blade and the wake are represented by a series of distributed vortices, and the shedding vortex at the trailing edge of the blade is replaced by the lift line or lift surface method. The induced velocity field of the vortex system is calculated according to the Biot-Savart law. The aerodynamic load of the blade can be predicted through the induced velocity.

[0034] like Figure 2 As shown in FIG. 1 , in the aerodynamic model, a concentrated line vortex whose vorticity varies along the span direction, i.e., an attached vortex, is used to simulate the vorticity distribution of the three-dimensional flow field of the wind turbine blade to represent the interaction between the blade and the flow field. The spiral tail vortex detached from the attached vortex flows downstream of the blade to infinity, forming an induced velocity field. This embodiment uses a rigid spiral tail vortex model to simulate the flow field of the wind turbine blade. The rigid spiral tail vortex and its coordinate system are shown in FIG. Figure 3 shown.

[0035] Step S102: Determine structural response information of the blade based on a pre-constructed blade structural model and the aerodynamic load of the blade.

[0036] In this embodiment, the blade structure model can simulate the displacement state of the blade before and after deformation and the precise relationship between strain and displacement.

[0037] Step S103: analyzing the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade.

[0038] Based on the method described in steps S101 to S103 above, the present application constructs an aerodynamic model based on the vortex wake method of lift lines, and determines the aerodynamic load of the blade based on the aerodynamic model; then, combining the blade structure model and the aerodynamic load, the structural response information of the blade can be determined, and then the elastic deformation of the blade caused by the unsteady aerodynamic load and its interaction can be predicted. The influence of the aeroelastic effect on the power generation performance and fatigue life of the wind turbine can be deeply understood, providing a reference for the reasonable design of wind turbine blades.

[0039] Steps S101 to S103 are further described below.

[0040] With respect to step S101, in one embodiment, determining the aerodynamic load of the blade based on a pre-constructed aerodynamic model includes: obtaining Fourier series expansion coefficients; determining the induced velocity of the attached vortex based on the Fourier series expansion coefficients; and determining the aerodynamic load of the blade based on the induced velocity of the attached vortex.

[0041] Specifically, the Fourier series expansion coefficient is the coefficient in the Fourier series expansion of the blade attached vortex ring, which is used to describe the distribution of the blade attached vortex ring. By solving the relevant linear equations, the Fourier series expansion coefficient is determined, and the induced velocity and aerodynamic load of the attached vortex are calculated.

[0042] The spiral wake theory calculates the induced velocity of the target point on the attached vortex based on the wake vortex, and then the distribution of the attached vortex circulation of the wind turbine blade can be obtained, and the aerodynamic load of the blade can be determined using the Kutta–Joukowski theorem.

[0043] According to the Biot-Savart law, the induced velocity can be expressed as:

[0044] Among them, W i is the induced velocity at the blade target point, Γ is the circulation of the attached vortex, l is the vector of the line vortex micro-segment pointing to the target point, ds is the line vortex micro-segment vector, and the shape of the rigid spiral tail vortex can be determined by the spatial position vector s, which can be expressed as: s=rcos(θ+θ k )i+rsin(θ+θ k )j+rθtan(φ)k (2)

[0045] Where r is the spanwise position of the blade where the attached vortex is shed; θ is the azimuth angle of the spiral tail vortex; θ k is the angle between the blade where the target point is located and the blade where the tail vortex starts; i, j, k are unit vectors, corresponding to the x, y, and z directions in the three-dimensional rectangular coordinate system, respectively; φ is the pitch angle of the spiral tail vortex, which is related to the incoming wind speed and the blade speed. φ can be expressed as:

[0046] Among them, w y It is the component of the induced velocity in the y direction, indicating the radial induced velocity component; U is equal to the incoming wind speed V0; Ω is the blade rotation speed.

[0047] In one embodiment, the obtaining of Fourier series expansion coefficients includes: obtaining wind speed information, blade parameters, wind rotor information and arbitrary position information; determining an induced velocity calculation formula for an attached vortex based on the wind speed information, the blade parameters, the wind rotor information and the arbitrary position information; determining an induced angle of attack based on the induced velocity calculation formula for the attached vortex and the wind speed information; determining a geometric angle of attack based on the wind speed information, the blade parameters and the wind rotor information; determining an effective angle of attack based on the induced angle of attack, the geometric angle of attack, and the corresponding relationship between the induced angle of attack, the geometric angle of attack and the effective angle of attack; determining a lift coefficient based on the induced velocity calculation formula for the attached vortex; and determining Fourier series expansion coefficients based on the effective angle of attack and the lift coefficient.

[0048] Specifically, the calculation formula for the induced velocity of the attached vortex is derived based on formula (1), formula (2), wind speed information, blade parameters, rotor information and arbitrary position information, where wind speed information refers to the incoming wind speed; blade parameters refer to blade speed, blade number, and blade serial number; rotor information refers to rotor cone angle and rotor radius; arbitrary position information refers to the spanwise position of the attached vortex where the attached vortex falls off and any spanwise position of the attached vortex. The calculation formula for the induced velocity of the attached vortex is as follows: R L =Rcosψ (5) N1=ξ 2 -ξξ′cos(θ+θ k ) (6) D2=λ0 2 +ξ′ 2 (9)

[0049] Among them, Wn is the induced velocity; Γ is the initial circulation of the attached vortex; R is the radius of the wind wheel; ξ=r / R, ξ'=r' / R, are dimensionless position parameters of the blade spanwise; r is the blade spanwise position where the attached vortex falls off; r' is any position of the attached vortex in the blade spanwise; λ0=V0 / (RΩ), V0=U, is the incoming wind speed; Ω is the blade speed; θ is the azimuth of the spiral tail vortex; θ k is the angle between the blade where the target point is located and the blade where the tail vortex starts; ψ is the wind wheel cone angle; N is the number of blades; K is the blade number where the target point is located.

[0050] Based on the calculation formula of the induced velocity of the attached vortex and the wind speed information, the calculation formula of the induced angle of attack is derived, where the wind speed information refers to the incoming wind speed. The calculation formula of the induced angle of attack is as follows:

[0051] Among them, α i is the induced angle of attack; V h V is the vibration speed of the blade in the swinging direction; b is the vibration speed of the blade in the swing direction.

[0052] Based on wind speed information, blade parameters and wind rotor information, the geometric angle of attack calculation formula is derived, where wind speed information refers to the incoming wind speed, blade parameters refer to the blade speed, and wind rotor information refers to the wind rotor radius. The geometric angle of attack calculation formula is as follows:

[0053] α g is the geometric angle of attack; β is the pitch angle.

[0054] The effective angle of attack is determined based on the induced angle of attack, the geometric angle of attack, and the corresponding relationship between the induced angle of attack, the geometric angle of attack and the effective angle of attack, wherein the corresponding relationship between the induced angle of attack, the geometric angle of attack and the effective angle of attack is expressed as: α e =α i +α g (14)

[0055] Among them, α e is the effective angle of attack.

[0056] According to the Kutta–Joukowski theorem, the relationship between circulation and lift coefficient can be expressed as: Γ=0.5cWC L (15)

[0057] Where Γ is the initial circulation of the attached vortex; c is the chord length of the airfoil; W is the relative wind speed; C L is the lift coefficient.

[0058] In the small angle of attack range, such as the angle of attack in the range of 0 to 10 degrees, the lift coefficient and the effective angle of attack can be approximated as a linear relationship: C L =a0α e +b0 (16)

[0059] Among them, a0 is the slope; b0 is the intercept; α e is the effective angle of attack.

[0060] The relative wind speed W can be expressed as: W=W n / cos(α i ) (17)

[0061] Since the circulation term Γ in the induced velocity calculation formula is unknown, the circulation of the attached vortex is assumed to be a Fourier series, satisfying the boundary condition Γ(ξ)=Γ(1)=0. Since the section of the blade close to the center of the hub is cylindrical, its section lift coefficient is always 0 at any angle of attack, that is, the circulation is always 0. Then the circulation function is assumed to be:

[0062] Among them, A m It is the coefficient in the Fourier series expansion used to represent the circulation, which is used to describe the circulation distribution of the vortex ring; m is the harmonic number in the Fourier series expansion.

[0063] Then, the induced velocity and circulation function of the attached vortex are substituted into the relationship formula between circulation and lift coefficient (15) to obtain the lift coefficient.

[0064] Substituting the lift coefficient and the effective angle of attack into the relationship between circulation and lift coefficient (15), we obtain:

[0065] Determine the Fourier series expansion coefficient A based on formula (19): m The initial solution of .

[0066] In one embodiment, determining the induced velocity of the attached vortex based on the Fourier series expansion coefficients includes: determining the initial circulation of the attached vortex based on the Fourier series expansion coefficients; updating the effective angle of attack based on the initial circulation of the attached vortex; updating the Fourier series expansion coefficients based on the initial circulation of the attached vortex and the updated effective angle of attack; updating the initial circulation of the attached vortex based on the updated Fourier series expansion coefficients; determining the induced velocity of the attached vortex based on the updated initial circulation of the attached vortex and a calculation formula for the induced velocity of the attached vortex.

[0067] Specifically, the initial solution of the Fourier series expansion coefficient is substituted into the circulation function formula (18) to obtain the initial circulation of the attached vortex; the initial circulation of the attached vortex is substituted into formula (15) to obtain the lift coefficient, and the new effective angle of attack is obtained using the lift coefficient and formula (16) representing the linear relationship between the lift coefficient and the effective angle of attack; the new Fourier series expansion coefficient is solved according to the updated effective angle of attack and the initial circulation of the attached vortex.

[0068] Then, the updated Fourier series expansion coefficients are used to determine the initial circulation of the new attached vortex, that is, the circulation function; based on the updated initial circulation of the attached vortex and formula (4), the induced velocity of the attached vortex is determined.

[0069] In one embodiment, determining the aerodynamic load of the blade based on the induced velocity of the attached vortex includes: iteratively calculating the effective angle of attack and the induced angle of attack based on the induced velocity of the attached vortex until the effective angle of attack and the induced angle of attack meet preset accuracy requirements; determining a final lift coefficient and a drag coefficient based on the effective angle of attack and the induced angle of attack that meet the preset accuracy requirements; determining the aerodynamic load of the blade based on the final lift coefficient and the drag coefficient, the aerodynamic load including axial thrust, rotational torque and power.

[0070] Specifically, an iterative method is used to calculate new effective angle of attack and induced angle of attack through the above formula and the induced velocity of the attached vortex until the effective angle of attack and the induced angle of attack meet the preset numerical accuracy.

[0071] According to the specific airfoil of the blade, obtain the corresponding preset airfoil lift and drag coefficient data table, find the two angles of attack closest to the effective angle of attack in the data table through the determined effective angle of attack, determine the interval where the effective angle of attack is located, and then calculate the final lift coefficient and drag coefficient corresponding to the effective angle of attack through linear interpolation or polynomial interpolation and other methods.

[0072] Then, according to the final lift coefficient and drag coefficient, the aerodynamic load of the blade is determined using the following formula, where the aerodynamic load includes axial thrust, rotational torque and power.

[0073] The calculation formula for axial thrust is:

[0074] The formula for calculating the torque is:

[0075] The power calculation formula is:

[0076] Where ρ is the air density and φ′ is the actual inflow angle.

[0077] The above is the description of step S101 , and the following is a further description of step S102 .

[0078] With respect to step S102, in one embodiment, determining the structural response information of the blade based on a pre-constructed blade structural model and the aerodynamic load of the blade includes: taking the aerodynamic load of the blade as an input of the blade structural model, and determining the structural response information of the blade under the action of the aerodynamic load, wherein the blade structural model is constructed based on geometrically precise beam theory.

[0079] Specifically, the wind turbine blade is simulated as a beam element, and the blade structure model of the blade is constructed based on the geometrically accurate beam theory. The geometrically accurate beam theory is a large deformation beam model that fully describes the displacement state of the beam before and after deformation, as well as the precise relationship between strain and displacement. The deformation state of the beam is as follows: Figure 4 As shown in the figure, no simplification is made to the displacement field and strain field during the derivation process. The aerodynamic load of the blade is used as the input of the blade structure model, and based on the corresponding structural parameters of the blade, such as stiffness and damping, the node degrees of freedom are numerically realized by Legendre spectrum finite element. The trapezoidal quadrature method is used to model the wind turbine blade with a single unit, and the Wiener-Milenkovic parameter is used to represent the three-dimensional rotation to obtain the linear displacement and angular displacement of each node of the blade. Secondly, the nonlinear motion control equation is solved by Newton's iteration method. After linearization, the generalized α time integrator is used to determine whether the nonlinear equation converges. If it converges, the iteration ends; otherwise, the iteration continues until the convergence standard is met.

[0080] The governing equations of the nonlinear motion of the geometrically accurate beam theory are:

[0081] Among them, h is linear momentum; g is angular momentum; t is time; F is the force on the cross section; M is the moment on the cross section; u is the one-dimensional displacement on the reference axis: x0 is the initial position vector of the point along the reference line; f is the distributed force applied to the beam; m is the distributed moment applied to the beam.

[0082] Based on the small strain assumption, the relationship between momentum and velocity, strain and cross-sectional force is:

[0083] Among them, M1 is the section mass; K is the stiffness matrix; ε is the one-dimensional strain; κ is the one-dimensional curvature; v is the linear velocity; ω is the angular velocity.

[0084] One-dimensional strain and curvature are defined as:

[0085] Among them, R is the rotation tensor; R0 is the initial rotation tensor; k is the curvature vector of the section; l1 is the unit vector along the s-axis; x'0 is the derivative of the initial position vector with respect to the s-axis, and u' is the derivative of the displacement vector with respect to the s-axis.

[0086] The nonlinear governing motion equations of the beam are solved by the Newton-Raphson method, and the incremental equations are discretized using the Legendre spectral finite element method. In linear analysis, the displacement is assumed to be infinitesimal, so the object's configuration remains unchanged, but under large deformations, it is necessary to establish equations with the reference configuration as the known configuration. If the governing equations of the approximate solution obtained by linearization are derived, the stress and strain can be referenced to the known configuration. First, the nonlinear motion governing equations need to be linearized. The linearized form of the nonlinear motion governing equations is as follows:

[0087] in, is the unit mass matrix; is the rotation matrix; is the stiffness matrix; is the generalized element acceleration, is the generalized speed, is the generalized node displacement array increment; Apply loads externally; is the unit force.

[0088] The geometrically accurate beam theory considers the cross-sectional rotation and torsion degrees of freedom, where the three-dimensional rotation can be represented by the Wiener-Milenkovic parameters, which can be expressed as:

[0089] in, is the rotation angle, and n is the unit vector of the rotation axis.

[0090] The above is the description of step S102 , and the following is a further description of step S103 .

[0091] For step S103, in one embodiment, the aerodynamic elasticity of the blade is analyzed based on the aerodynamic load and structural response information of the blade, including: iteratively calculating the aerodynamic load and structural response information of the blade based on the aerodynamic model, the blade structural model, the structural response information of the blade and the aerodynamic load until the aerodynamic load and structural response information of the blade meet the preset convergence conditions; and analyzing the aerodynamic elasticity of the blade based on the aerodynamic load and structural response information of the blade that meet the preset convergence conditions.

[0092] Specifically, the aeroelastic model of the flexible blade is established through data transfer between the aerodynamic model and the blade structure model. The final lift coefficient and drag coefficient of the blade are obtained using the aerodynamic model, and then the aerodynamic loads such as the blade axial thrust and torque are obtained based on the final lift coefficient and drag coefficient.

[0093] In each time step, the aerodynamic load of the blade is input into the blade structural model, and the structural response information such as deformation, stress and strain of the blade is solved. The structural response information is fed back to the aerodynamic model, and the lift surface calculation grid is regenerated according to the deformation of the blade. The geometry and boundary conditions of the aerodynamic model are updated, the wake vortex and attachment vortex distribution are solved and updated, and the new aerodynamic load caused by the deformation is recalculated. The steps of aerodynamic analysis and structural dynamics analysis are repeated for multiple iterations. In each time step, the aerodynamic load and structural response information are updated until both converge.

[0094] Since the structural response is solved in an implicit format, the data coupling within each time step needs to adopt a prediction-correction method. The prediction-correction data exchange method of the aerodynamic model of the aeroelastic model and the blade structure model coupling is as follows: Figure 5 shown.

[0095] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present application, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted schemes are equivalent to the technical schemes described in this application, and therefore will also fall within the scope of protection of this application.

[0096] It is understood by those skilled in the art that all or part of the processes in the method for implementing the above-mentioned embodiment of the present application can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0097] See attached Figure 6 , Figure 6 is a schematic diagram of the main structure of a wind turbine blade aeroelastic analysis system according to an embodiment of the present application; Figure 6As shown, another aspect of the present application also provides an aeroelastic analysis system for wind turbine blades. The aeroelastic analysis system for wind turbine blades in the embodiment of the present application mainly includes an aerodynamic load determination module 61, a structural response information determination module 62 and an analysis module 63. In some embodiments, one or more of the aerodynamic load determination module 61, the structural response information determination module 62 and the analysis module 63 can be combined into one module. In some embodiments, the aerodynamic load determination module 61 can be configured to determine the aerodynamic load of the blade based on a pre-constructed aerodynamic model, wherein the aerodynamic model is constructed based on the vortex wake method of the lift line. The structural response information determination module 62 can be configured to determine the structural response information of the blade based on a pre-constructed blade structural model and the aerodynamic load of the blade. The analysis module 63 can be configured to analyze the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade. In one embodiment, the description of the specific implementation function can be referred to the description of steps S101-step S103.

[0098] The above-mentioned wind turbine blade aeroelastic analysis system is used to perform Figure 1 The embodiment of the aeroelastic analysis method for wind turbine blades shown in the figure has similar technical principles, technical problems solved and technical effects produced. Technicians in this technical field can clearly understand that for the convenience and conciseness of description, the specific working process and related instructions of the aeroelastic analysis system for wind turbine blades can refer to the contents described in the embodiment of the aeroelastic analysis method for wind turbine blades, and will not be repeated here.

[0099] Another aspect of the present application provides an electronic device.

[0100] See attached Figure 7 , Figure 7 In the figure, it is exemplarily shown that the memory 11 and the processor 12 are connected in communication via a bus. In an embodiment of an electronic device according to the present application, the electronic device may include at least one processor; and a memory connected in communication with the at least one processor; wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the aeroelastic analysis method of a wind turbine blade described in any of the above embodiments is implemented.

[0101] Another aspect of the present application also provides a computer-readable storage medium.

[0102] In an embodiment of a computer-readable storage medium according to the present application, the computer-readable storage medium may be configured to store a program for executing the aeroelastic analysis method of a wind turbine blade in the above-mentioned method embodiment, and the program may be loaded and run by a processor to implement the above-mentioned aeroelastic analysis method of a wind turbine blade. For ease of explanation, only the parts related to the embodiment of the present application are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present application. The computer-readable storage medium may be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiment of the present application is a non-temporary computer-readable storage medium.

[0103] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A method for aeroelastic analysis of wind turbine blades, characterized in that: The method comprises: Determining the aerodynamic load of the blade based on a pre-built aerodynamic model, wherein the aerodynamic model is built based on a vortex wake method of lift lines; Determining structural response information of the blade based on a pre-built blade structural model and aerodynamic loads of the blade; The aeroelasticity of the blade is analyzed based on the aerodynamic load and structural response information of the blade.

2. The aeroelastic analysis method for wind turbine blades according to claim 1, characterized in that: The method of determining the aerodynamic load of the blade based on the pre-built aerodynamic model comprises: Get the Fourier series expansion coefficients; determining the induced velocity of the attached vortex based on the Fourier series expansion coefficients; Based on the induced velocity of the attached vortex, the aerodynamic load of the blade is determined.

3. The aeroelastic analysis method for wind turbine blades according to claim 2, characterized in that: The obtaining of Fourier series expansion coefficients comprises: Obtain wind speed information, blade parameters, wind rotor information and any position information; Determine a calculation formula for the induced velocity of the attached vortex based on the wind speed information, the blade parameters, the wind wheel information and the arbitrary position information; Determining an induced angle of attack based on a calculation formula for the induced velocity of the attached vortex and the wind speed information; Determining a geometric angle of attack based on the wind speed information, the blade parameters and the wind rotor information; Determining an effective angle of attack based on the induced angle of attack, the geometric angle of attack, and a corresponding relationship between the induced angle of attack, the geometric angle of attack, and the effective angle of attack; Determining the lift coefficient based on the calculation formula of the induced velocity of the attached vortex; Based on the effective angle of attack and the lift coefficient, Fourier series expansion coefficients are determined.

4. The aeroelastic analysis method for wind turbine blades according to claim 3, characterized in that: The step of determining the induced velocity of the attached vortex based on the Fourier series expansion coefficient comprises: Determining the initial circulation of the attached vortex based on the Fourier series expansion coefficient; updating the effective angle of attack based on the initial circulation of the attached vortex; updating the Fourier series expansion coefficients based on the initial circulation of the attached vortex and the updated effective angle of attack; Based on the updated Fourier series expansion coefficients, updating the initial circulation of the attached vortex; The induced velocity of the attached vortex is determined based on the updated initial circulation of the attached vortex and the calculation formula of the induced velocity of the attached vortex.

5. The aeroelastic analysis method for wind turbine blades according to claim 4, characterized in that: The step of determining the aerodynamic load of the blade based on the induced velocity of the attached vortex comprises: Iteratively calculating the effective angle of attack and the induced angle of attack based on the induced speed of the attached vortex until the effective angle of attack and the induced angle of attack meet preset accuracy requirements; Determining a final lift coefficient and a drag coefficient based on the effective angle of attack and the induced angle of attack that meet the preset accuracy requirements; Based on the final lift coefficient and the drag coefficient, the aerodynamic load of the blade is determined, and the aerodynamic load includes axial thrust, rotational moment and power.

6. The aeroelastic analysis method of wind turbine blades according to claim 1, characterized in that: The determining of the structural response information of the blade based on the pre-built blade structural model and the aerodynamic load of the blade includes: The aerodynamic load of the blade is used as an input of the blade structure model to determine the structural response information of the blade under the action of the aerodynamic load, wherein the blade structure model is constructed based on geometrically accurate beam theory.

7. The aeroelastic analysis method for wind turbine blades according to claim 6, characterized in that: The aeroelastic analysis of the blade based on the aerodynamic load and structural response information of the blade includes: Based on the aerodynamic model, the blade structure model, the structural response information of the blade and the aerodynamic load, iteratively calculate the aerodynamic load and the structural response information of the blade until the aerodynamic load and the structural response information of the blade meet a preset convergence condition; The aeroelasticity of the blade is analyzed based on the aerodynamic load and structural response information of the blade that meets the preset convergence conditions.

8. A wind turbine blade aeroelastic analysis system, characterized in that: The system comprises: an aerodynamic load determination module, used to determine the aerodynamic load of the blade based on a pre-built aerodynamic model, wherein the aerodynamic model is built based on a vortex wake method of lift lines; A structural response information determination module, used to determine the structural response information of the blade based on a pre-built blade structural model and the aerodynamic load of the blade; The analysis module is used to analyze the aeroelasticity of the blade based on the aerodynamic load and structural response information of the blade.

9. An electronic device comprising at least one processor and at least one memory, wherein the memory is suitable for storing a plurality of program codes, wherein: The program code is suitable for being loaded and run by the processor to execute the wind turbine blade aeroelastic analysis method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a plurality of program codes, characterized in that: The program code is suitable for being loaded and run by a processor to execute the wind turbine blade aeroelastic analysis method according to any one of claims 1 to 7.

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