Aeroelastic analysis method, system and equipment for fan blade and medium

Abstract

The invention relates to the technical field of wind turbine generators, particularly provides an aeroelasticity analysis method, system and equipment of a fan blade and a medium, and aims to solve the aeroelasticity analysis problem of a flexible fan blade. Therefore, the aeroelasticity analysis method for the fan blade comprises the following steps: acquiring blade parameters and wind speed data of a to-be-analyzed blade; determining the aerodynamic load of the to-be-analyzed blade based on an aerodynamic model, the blade parameters and the wind speed data; based on the blade parameters and the aerodynamic load of the to-be-analyzed blade, determining the structural response of the to-be-analyzed blade; and carrying out aeroelasticity analysis on the to-be-analyzed blade based on the aerodynamic load and the structural response of the to-be-analyzed blade. The method is suitable for aeroelasticity analysis of the flexible blade of the wind turbine generator, and provides reliable reference for aeroelasticity stability evaluation of the flexible blade of the wind turbine generator.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbines, and in particular to an aeroelastic analysis method, system, equipment and medium for wind turbine blades. Background Art

[0002] As the most important structure of the entire wind turbine system, the aerodynamic characteristics of the blades are directly related to the output power of the wind turbine. With the increase in the capacity of a single wind turbine, the length of the blades continues to increase. Longer blades mean a larger swept area, which will cause a significant increase in the aerodynamic load on the wind turbine. In addition, the lightweight and flexible development trend of the blades makes the blades more prone to large geometric deformation. This deformation may make the aeroelastic problems of the wind turbine system more prominent and increase the risk of instability, thereby causing the blades to swing significantly and affecting the safe operation of the wind turbine.

[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 technical problem of aeroelastic analysis of flexible blades of wind turbines.

[0005] In a first aspect, a method for aeroelastic analysis of a wind turbine blade is provided, the method comprising: acquiring blade parameters and wind speed data of a blade to be analyzed; determining the aerodynamic load of the blade to be analyzed based on an aerodynamic model and the blade parameters and the wind speed data; determining the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load of the blade to be analyzed; and performing aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed.

[0006] In a technical solution of the above-mentioned aeroelastic analysis method of the wind turbine blade, the aerodynamic load of the blade to be analyzed is determined based on the aerodynamic model, the blade parameters and the wind speed data, including: determining the axial induction factor and the tangential induction factor based on the aerodynamic model, the blade parameters and the wind speed data; determining the aerodynamic load of the blade to be analyzed based on the determined axial induction factor and the tangential induction factor.

[0007] In a technical solution of the above-mentioned aeroelastic analysis method of a wind turbine blade, the blade to be analyzed includes a plurality of blade elements; the determining of the axial induction factor and the tangential induction factor based on the aerodynamic model, the blade parameters and the wind speed data includes: determining the incoming flow velocity based on the wind speed data and the blade parameters; determining the lift and drag on the blade element based on the incoming flow velocity; determining the normal force and tangential force acting on the blade element based on the lift and drag on the blade element; determining the thrust and torque on the micro-element ring at a preset distance based on the normal force and tangential force acting on the blade element; determining the thrust and torque acting on the micro-element ring at a preset distance based on the momentum theorem and the thrust and torque on the micro-element ring at a preset distance; determining the axial induction factor and the tangential induction factor based on the thrust and torque on the micro-element ring at a preset distance and the thrust and torque acting on the micro-element ring at the preset position.

[0008] In a technical solution of the above-mentioned aeroelastic analysis method of the fan blade, the aerodynamic load of the blade to be analyzed is determined based on the determined axial induction factor and tangential induction factor, including: based on the determined axial induction factor and tangential induction factor, the lift and drag acting on the blade element are integrated along the span direction of the blade to be analyzed to obtain the aerodynamic load of the blade to be analyzed.

[0009] In a technical solution of the above-mentioned aeroelastic analysis method of wind turbine blades, the structural response of the blade to be analyzed is determined based on the blade parameters and the aerodynamic load of the blade to be analyzed, including: obtaining the gravity load and inertia load of the blade to be analyzed; based on a pre-constructed blade nonlinear dynamic model, determining the structural response of the blade to be analyzed under the action of external loads, wherein the external loads include the gravity load, inertia load and aerodynamic load of the blade to be analyzed.

[0010] In a technical solution of the above-mentioned aeroelastic analysis method of wind turbine blades, the blade nonlinear dynamic model is constructed by the following steps: based on the blade parameters of the blade to be analyzed and the geometrically precise beam theory, the stiffness matrix, mass matrix and damping matrix of the blade to be analyzed are constructed; based on the stiffness matrix, mass matrix, damping matrix of the blade to be analyzed, as well as the linear momentum conservation equation, the relationship between the angular momentum change and the internal torque and the external torque, the blade nonlinear dynamic model is established.

[0011] In a technical solution of the above-mentioned aeroelastic analysis method of a wind turbine blade, the aeroelastic analysis of the blade to be analyzed is performed based on the aerodynamic load and the structural response of the blade to be analyzed, including: updating the aerodynamic load of the blade to be analyzed based on the structural response of the blade to be analyzed; determining a new structural response of the blade to be analyzed based on the updated aerodynamic load of the blade to be analyzed, and repeating the steps of updating the aerodynamic load of the blade to be analyzed and determining the new structural response of the blade to be analyzed until the updated aerodynamic load and the new structural response meet the preset convergence criteria; and analyzing the aeroelasticity of the blade based on the updated aerodynamic load and the new structural response to obtain an aeroelastic analysis result.

[0012] In a second aspect, an aeroelastic analysis system for wind turbine blades is provided, the system comprising: an acquisition module for acquiring blade parameters and wind speed data of a blade to be analyzed; an aerodynamic load determination module for determining the aerodynamic load of the blade to be analyzed based on an aerodynamic model, the blade parameters and the wind speed data; a structural response determination module for determining the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load of the blade to be analyzed; and an analysis module for performing aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed.

[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 aeroelastic analysis method of wind turbine blades is implemented.

[0014] In a fourth aspect, a computer-readable storage medium is provided, in which a plurality of program codes are stored, 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 aeroelastic analysis method for wind turbine blades.

[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 of wind turbine blades provided in the present application includes: obtaining blade parameters and wind speed data of the blade to be analyzed; determining the aerodynamic load of the blade to be analyzed based on the aerodynamic model and the blade parameters and the wind speed data; determining the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load on the blade; and performing aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed. The present application determines the aerodynamic load of the wind turbine blade based on the aerodynamic model, and determines the structural response of the blade to be analyzed based on the aerodynamic load on the blade. The aeroelastic analysis of the flexible blades of the wind turbine set is performed in combination with the aerodynamic load and structural response of the wind turbine blade, which can provide a reliable reference for the aeroelastic stability evaluation of the long flexible blades of the wind turbine set, and further understand the influence of the aeroelastic effect on the power generation performance and fatigue life of the wind turbine, guide the blade design, and thus improve the service life of the blade. 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 It is a schematic flow chart of the main steps of the aeroelastic analysis method of a wind turbine blade according to one embodiment of the present application;

[0019] Figure 2 is a schematic diagram of the velocity synthesis relationship and aerodynamic force under blade element rotation conditions according to an embodiment of the present application;

[0020] Figure 3 is a schematic diagram of a beam deformation state according to an embodiment of the present application;

[0021] Figure 4 is a schematic diagram of detailed steps of an aeroelastic analysis method for a wind turbine blade according to an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of the main structure of an aeroelastic analysis system for a wind turbine blade according to an embodiment of the present application;

[0023] Figure 6 It is a schematic diagram of the main structure of an electronic device according to an embodiment of the present application.

[0024] Reference numerals:

[0025] 11: memory; 12: processor; 51: acquisition module; 52: aerodynamic load determination module; 53: structural response determination module; 54: analysis module. DETAILED DESCRIPTION

[0026] 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.

[0027] 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.

[0028] See attached Figure 1 , Figure 1 FIG. 1 is a flow chart of the main steps of the aeroelastic analysis method of a fan blade according to an embodiment of the present application. Figure 1 As shown, the aeroelastic analysis method of a wind turbine blade in the embodiment of the present application mainly includes the following steps S101 to S104.

[0029] Step S101: Obtain blade parameters and wind speed data of the blade to be analyzed.

[0030] Step S102: determining the aerodynamic load of the blade to be analyzed based on the aerodynamic model, the blade parameters, and the wind speed data.

[0031] Step S103: determining the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic loads of the blade to be analyzed.

[0032] Step S104: performing an aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed.

[0033] Based on the methods described in steps S101 to S104 above, the present application determines the aerodynamic load of the wind turbine blade based on the aerodynamic model, and determines the structural response of the blade to be analyzed based on the aerodynamic load on the blade, and then analyzes the aerodynamic elasticity of the flexible blades of the wind turbine in combination with the aerodynamic load and structural response of the wind turbine blade, which can provide a reliable reference for the aerodynamic elastic stability evaluation of the flexible blades of the wind turbine.

[0034] The above steps S101 to S104 are further explained below.

[0035] With respect to step S101 , blade parameters and wind speed data of the blade to be analyzed are obtained.

[0036] Specifically, the blade parameters of the blade to be analyzed may be parameters such as the rotor speed, the geometric shape and material of the blade; the wind speed data may be a time series of wind speeds, including free stream velocity.

[0037] For step S102, the aerodynamic load of the blade to be analyzed is determined based on the aerodynamic model, the blade parameters, and the wind speed data, including: determining the axial induction factor and the tangential induction factor based on the aerodynamic model, the blade parameters, and the wind speed data; determining the aerodynamic load of the blade to be analyzed based on the determined axial induction factor and the tangential induction factor.

[0038] Specifically, an aerodynamic model is constructed based on the blade element momentum theory, which includes blade element theory and momentum theory. The blade element theory equates the blade to a series of annular segments, called "microelement rings". Microelement rings include several microelement segments, each of which is a blade element. By integrating the lift and drag acting on the blade element along the span direction, the aerodynamic load of the blade to be analyzed can be obtained, that is, the aerodynamic thrust and torque of the blade to be analyzed. Momentum theory can calculate the thrust and torque of the microelement ring at any radius position within the swept surface of the wind rotor.

[0039] The airflow will be disturbed when passing through the blades and the rotating plane of the wind wheel, and the axial and tangential velocities of the airflow will change. The axial induction factor a and the tangential induction factor b are introduced to reflect the degree of reduction in the tangential and axial speeds of the airflow when passing through the wind wheel. According to the obtained blade parameters and wind speed data of the blade to be analyzed, the axial induction factor and the tangential induction factor are first determined, and then the aerodynamic load of the blade to be analyzed is calculated based on the determined axial induction factor and tangential induction factor.

[0040] In one embodiment, the blade to be analyzed includes a plurality of blade elements; the determining of the axial induction factor and the tangential induction factor based on the aerodynamic model, the blade parameters and the wind speed data includes: determining the incoming flow velocity based on the wind speed data and the blade parameters; determining the lift and drag on the blade element based on the incoming flow velocity; determining the normal force and tangential force acting on the blade element based on the lift and drag on the blade element; determining the thrust and torque on the micro-element ring at a preset position based on the normal force and tangential force acting on the blade element; determining the thrust and torque acting on the micro-element ring at a preset position based on the momentum theorem and the thrust and torque on the micro-element ring at a preset position; determining the axial induction factor and the tangential induction factor based on the thrust and torque on the micro-element ring at a preset position and the thrust and torque acting on the micro-element ring at the preset position.

[0041] See attached Figure 2 , Figure 2 FIG. 1 is a schematic diagram of the velocity synthesis relationship and aerodynamic force under blade element rotation conditions according to an embodiment of the present application. Figure 2 As shown, the wind speed data includes the free flow velocity, and the blade parameters include the radius of the blade element at the blade position, the blade chord length, the number of blades, the blade diameter, and the wind rotor speed. Based on the free flow velocity and the axial induction factor, the axial induced velocity of the airflow is determined; the axial induced velocity of the airflow can be expressed as: v d =V(1-a)

[0042] Based on the wind wheel speed, the radius of the blade element at the blade position, and the tangential induction factor, the tangential induced velocity of the airflow is determined; the tangential induced velocity of the airflow can be expressed as: v t =Ωr(1+b)

[0043] Among them, v d is the axial induced velocity of the airflow, v t is the tangential induced velocity of the airflow, a is the axial induction factor, b is the tangential induction factor, V is the free flow velocity, Ω is the wind wheel speed, and r is the radius of the blade position where the current blade element is located.

[0044] Based on the axial induced velocity of the airflow and the tangential induced velocity of the airflow, the incoming flow velocity is determined; the incoming flow velocity can be expressed as:

[0045] Where W is the combined velocity of the incoming flow, V is the free incoming flow velocity, a is the axial induction factor, b is the tangential induction factor, and the relationship between a and b is b = 1-a. φ is the inflow angle; Ω is the wind wheel speed; r is the radius of the blade position where the current blade element is located.

[0046] The relationship between the inflow angle φ, the angle of attack α and the pitch angle β is: α=φ-β

[0047] The blade to be analyzed includes multiple blade elements, and the lift force dF of each blade element is l and resistance dF d It can be expressed as:

[0048] Where ρ is the air density, W is the combined velocity of the incoming flow, c is the chord length, C L is the airfoil lift coefficient, C D is the airfoil drag coefficient, and r is the radius of the blade at the current blade element.

[0049] The lift and drag acting on the blade element are decomposed into the direction of the wind rotor rotation plane and the direction perpendicular to the wind rotor rotation plane, and the normal force F acting on the blade element is obtained. n and the tangential force F t , normal force F n Also called axial thrust, tangential force F t Multiplying by the radius r gives the torque.

[0050] The normal force F acting on the blade element n The calculation formula is:

[0051] Among them, dF l is the lift force, dF d For resistance, ρ is air density, W is the combined velocity of the incoming flow, c is the blade chord length, C n is the normal force coefficient, and r is the radius of the blade where the current blade element is located.

[0052] Normal force coefficient C n It can be expressed as: C n =C L cosφ+C D sinφ

[0053] The tangential force F acting on the blade element t The calculation formula is:

[0054] Among them, dF l is the lift force, dF d For resistance, ρ is the air density, W is the combined velocity of the incoming flow, c is the chord length, C t is the tangential force coefficient, and r is the radius of the blade where the current blade element is located.

[0055] Tangential force coefficient Ct It can be expressed as: C t =C L sinφ-C D cosφ

[0056] Based on the determined normal force and tangential force acting on the blade element, the following formula is used to determine the thrust and torque of the micro-element ring at the preset position:

[0057] Among them, dT 叶素 is the thrust of the microelement ring at the preset position, dM 叶素 is the torque of the microelement ring at the preset position, B is the number of blades, ρ is the air density, W is the combined velocity of the incoming flow, c is the blade chord length, C n is the normal force coefficient, C t is the tangential force coefficient, and r is the radius at the preset position, that is, the radius of the blade position where the current blade element is located.

[0058] Based on the momentum theorem and the thrust and torque on the micro-ring at the preset position, the thrust and torque acting on the micro-ring at the preset position are determined. The calculation formula is as follows: dT 动量 =4πρrV 2 (1-a)adr dM 动量 =4πρr 3 VΩ(1-a)bdr

[0059] Among them, dT 动量 is the thrust acting on the microelement ring at the preset position, dM 动量 is the torque acting on the micro-element ring at the preset position, ρ is the air density, V is the free flow velocity, a is the axial induction factor, b is the tangential induction factor, and r is the radius at the preset position, that is, the blade position where the current blade element is located.

[0060] Based on the thrust and torque on the micro-element ring at the preset position, and the thrust and torque acting on the micro-element ring at the preset position, dT 叶素 =dT 动量 , dM 叶素 =dM 动量 , after sorting, we can get:

[0061] Initialize the axial induction factor a to 0, determine the inflow angle φ, substitute all the above formulas to determine the next new axial induction factor, compare the new axial induction factor a with the axial induction factor a of the previous iteration, if the difference between the two meets the preset threshold, it is considered to be converged, and the axial induction factor a and the tangential induction factor b are determined, otherwise repeat the above process.

[0062] In one embodiment, determining the aerodynamic load of the blade to be analyzed based on the determined axial induction factor and tangential induction factor includes: integrating the lift and drag exerted on the blade element along the span direction of the blade to be analyzed based on the determined axial induction factor and tangential induction factor to obtain the aerodynamic load of the blade to be analyzed.

[0063] Specifically, the aerodynamic load of the blade to be analyzed includes the thrust and torque of the blade to be analyzed. Based on the determined axial induction factor and tangential induction factor, the lift and drag of the blade element are integrated along the span direction of the blade to be analyzed to obtain the aerodynamic load of the blade to be analyzed. The calculation formula is as follows:

[0064] Where T is the thrust of the blade to be analyzed, M is the torque of the blade to be analyzed, and R h is the hub diameter of the wind wheel, R is the blade diameter, ρ is the air density, V is the free flow velocity, Ω is the wind wheel speed, a is the axial induction factor, b is the tangential induction factor, and r is the radius at the preset position, that is, the radius of the blade position where the current blade element is located.

[0065] For step S103, the determining the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load of the blade to be analyzed includes: acquiring the gravity load and the inertia load of the blade to be analyzed; and determining the structural response of the blade to be analyzed under the action of external loads based on a pre-constructed blade nonlinear dynamic model, wherein the external loads include the gravity load, inertia load and aerodynamic load of the blade to be analyzed.

[0066] Specifically, gravity load and inertia load are mainly static load and dynamic load caused by gravity, vibration, rotation and earthquake. Both inertia load and gravity load are loads generated by mass. The gravity load acting on the blade will generate bending moment in the blade swing direction. When the wind wheel rotates, the bending moment in the blade swing direction changes periodically with the change of the blade azimuth angle. The following formula can be used to obtain the gravity load of the blade:

[0067] or, F g=m blade g

[0068] Among them, F g is the gravity load, m i is the mass of the i-th leaf element of the leaf to be analyzed, g is the gravity coefficient, m blade is the mass of the blade to be analyzed.

[0069] The inertial load mainly depends on the angular velocity, radius and blade unit mass of the wind rotor. C The calculation is done using the following formula:

[0070] Among them, F C is the inertia load, m i is the mass of the i-th leaf element of the leaf to be analyzed, r i is the radius of the i-th blade element, and Ω is the wind wheel speed.

[0071] The determined gravity load, inertia load and aerodynamic load of the blade to be analyzed are taken as external loads, and the stiffness matrix, mass matrix and damping matrix of the blade to be analyzed are calculated; the structural response of the blade to be analyzed under the action of the external load is calculated through the pre-constructed blade nonlinear dynamic model.

[0072] In one embodiment, the nonlinear dynamic model of the blade is constructed by the following steps: based on the blade parameters of the blade to be analyzed and the geometrically precise beam theory, the stiffness matrix, mass matrix and damping matrix of the blade to be analyzed are constructed; based on the stiffness matrix, mass matrix, damping matrix of the blade to be analyzed, as well as the linear momentum conservation equation, the relationship between the angular momentum change and the internal torque and the external torque, the nonlinear dynamic model of the blade is established.

[0073] Geometrically accurate beam theory is based on the Reissner beam theory and also uses the flat section assumption, but does not use the small rotation approximation. It describes the cross-sectional motion under large deformations more accurately through the three-dimensional finite rotation theory. Through a three-dimensional cross-sectional analysis, all coupling effects of the six degrees of freedom, including tension, shear, torsion, bending, torsional warping, in-plane warping, etc., can be covered by geometrically accurate beam theory. "Geometrically accurate" means that no approximation is made in the formula for the initial geometry and the deformed geometry.

[0074] Specifically, the blade to be analyzed is simplified into a beam unit. Based on the blade parameters and external loads of the blade to be analyzed, the degree of freedom of each node is calculated by the Legendre spectral finite element method, and the trapezoidal quadrature method is used to model the wind turbine blade to be analyzed using a single beam unit. The Wiener-Milenkovic parameter is used to represent the three-dimensional rotation, and the displacement information of each node of the blade to be analyzed is obtained. The displacement information includes linear displacement and angular displacement. Then, the nonlinear motion control equation is solved by Newton-Raphson. After linearization, the generalized α time integrator (Generalizedαmethod) is used for time integration. After each iteration, check whether the nonlinear equation converges. If converged, the iteration ends; otherwise, the iteration continues until the convergence criterion is met.

[0075] See attached Figure 3 , Figure 3 FIG. 1 is a schematic diagram of a beam deformation state according to an embodiment of the present application. Figure 3 As shown in the figure, the blade nonlinear dynamic model is constructed by the following steps:

[0076] The governing equations of nonlinear motion for geometrically accurate beam theory are as follows:

[0077] The first formula above is the linear momentum conservation equation of the beam, which describes the linear motion change of the beam under the action of external force. Among them, h is the linear momentum in the inertial coordinate system, It represents the rate of change of momentum h with time, the symbol F represents the cross-sectional force of the beam, F' is the rate of change of the cross-sectional force F of the beam along the axis s of the beam, and f is the distributed force applied to the beam structure.

[0078] The second formula above describes the relationship between the change in angular momentum of the beam and the internal and external moments. g is the angular momentum in the inertial coordinate system, is the rate of change of angular momentum with time; u represents the linear displacement of a point on the reference line, which refers to the displacement of the beam after being subjected to force; M represents the cross-sectional moment of the beam, M' is the rate of change of the bending moment M along the s direction of the beam axis; x0 represents the position vector of the reference point along the beam, the superscript "(·)" represents the derivative with respect to time, the right superscript "(')" represents the derivative with respect to the s axis, and the superscript Indicates that this is a cross product matrix, mainly used to describe the rotation effect.

[0079] The constitutive equations relate velocity to momentum and one-dimensional strain to cross-sectional results, yielding:

[0080] Where M is the 6×6 section mass matrix; C is the 6×6 section stiffness matrix; ε is the one-dimensional strain, k is the curvature; ω is the angular velocity vector defined by the rotation tensor R, where ω = axial (RR T ).

[0081] The vector a is associated with a second-order tensor A, whose components are defined as:

[0082] The one-dimensional strain ε and curvature k can be expressed as:

[0083] Where K is the cross-sectional curvature vector decomposed on the basis of inertia, K = axial[(RR0)'(RR0) T ], R is the current rotation tensor, R0 is the initial rotation tensor, (RR0) T is the transposed matrix of (RR0), l1 is the unit vector along the s-axis in the inertial basis, 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.

[0084] The above equations together constitute a mathematical description of the geometrically accurate beam elastic problem. Based on the above equations and the blade parameters of the blade to be analyzed, the stiffness matrix, mass matrix and damping matrix of the blade to be analyzed are determined.

[0085] The nonlinear dynamic model of the blade can be expressed as: Ma+Gv+Kq=F

[0086] Among them, M is the mass matrix, G is the damping matrix, K is the stiffness matrix; a is the generalized element acceleration, v is the generalized velocity, q is the generalized displacement array, and F is the external load.

[0087] The blade nonlinear dynamic model needs to be solved by the Newton-Raphson method, and the incremental equations are discretized using the Legendre spectrum finite element method. The linearized form of the blade nonlinear dynamic model is as follows:

[0088] in, is the unit mass matrix, is the element damping matrix, is the element stiffness matrix; is the generalized element acceleration, is the generalized speed, is the generalized node displacement array increment; Represents externally applied load; Expressed as unit force.

[0089] When solving the nonlinear dynamic equations of wind turbine blades, a generalized alpha time integrator is used to calculate the time integral. In each time step, the nonlinear equations need to be solved, and the calculation in the current time step is considered to have converged only when the difference between the solutions of two adjacent time steps is less than the preset convergence tolerance.

[0090] The geometrically accurate beam theory uses the energy stopping criterion as a method of judging convergence. It determines whether the convergence criterion has been reached by comparing the internal energy increment at each iteration with the initial internal energy increment. This criterion provides a measure of when the displacements and forces are close to their equilibrium values. The internal energy increment refers to the change in the energy stored in the structure during each iteration. The initial internal energy increment refers to the internal energy increment calculated at the first iteration. |ΔU (i)T ( t+Δt R- t+Δt F (i-1) )|≤|ε E [ΔU (1)T ( t+Δ R- t F)]|

[0091] Where ΔU is the increment of the displacement vector; R is the externally applied node load vector; F is the node force vector corresponding to the internal unit stress; ε E is the preset energy tolerance; the superscript on the left side of the variable indicates the time variable, indicating that it is in dynamic analysis; the superscript on the right side indicates the number of iterations of the Newton-Raphson method.

[0092] The three-dimensional rotation of the geometrically accurate beam theory is expressed using Wiener-Milenkovic parameters and can be expressed as:

[0093] in, is the rotation angle, and n is the unit vector of the rotation axis.

[0094] Based on the assumption that there are p+1 nodes in the beam element, the internal linear displacement u and angular displacement θ of the beam element are interpolated by the following formulas:

[0095] Among them, h k (ξ) is the shape function of the kth node, u k is the linear displacement of the kth node, θ k is the angular displacement of the kth node. ξ is the local coordinate of the element, which is used to describe the position inside the element.

[0096] With respect to step S104, the aerodynamic load and the structural response of the blade to be analyzed are used to perform an aeroelastic analysis on the blade to be analyzed, including: updating the aerodynamic load of the blade to be analyzed based on the structural response of the blade to be analyzed; determining a new structural response of the blade to be analyzed based on the updated aerodynamic load of the blade to be analyzed, and repeating the steps of updating the aerodynamic load of the blade to be analyzed and determining the new structural response of the blade to be analyzed until the updated aerodynamic load and the new structural response meet a preset convergence criterion; and analyzing the aeroelasticity of the blade based on the updated aerodynamic load and the new structural response to obtain an aeroelastic analysis result.

[0097] Specifically, within a time step, after determining the aerodynamic load of the blade to be analyzed, the gravity load and inertia load of the blade to be analyzed are determined, and the aerodynamic load, gravity load and inertia load are used as the external loads on the blade to be analyzed. The mass matrix, damping matrix and stiffness matrix are constructed based on the blade parameters of the blade to be analyzed, such as material stiffness, inertia and damping, and based on the established blade nonlinear dynamic model, the structural response of the blade to be analyzed under the action of the external load is solved by the Newton-Raphson method, and then the structural response of the blade to be analyzed is fed back to the aerodynamic model. The lift coefficient and drag coefficient are re-determined according to the local free flow velocity and angle of attack after the deformation of the blade structure to be analyzed, and the calculation of the next time step is performed after the aerodynamic shape of the blade to be analyzed is updated.

[0098] This application couples the aerodynamic model of wind turbine blades based on blade element momentum theory and the nonlinear dynamic model of blades with nonlinear and large deflection deformation based on geometrically precise beam theory to construct an aeroelastic analysis method suitable for large flexible blades, which can provide a reliable reference for the aeroelastic stability evaluation of flexible blades of wind turbines.

[0099] See attached Figure 4 , Figure 4 Detailed step flow diagram of a method for aeroelastic analysis of a fan blade according to an embodiment of the present application. In this embodiment, the method for aeroelastic analysis of a fan blade includes the following steps:

[0100] Step S401: Start.

[0101] Step S402: Obtain blade parameters and wind speed data of the blade to be analyzed.

[0102] Step S403: Determine the aerodynamic load of the blade to be analyzed based on the aerodynamic model, blade parameters, and wind speed data.

[0103] Step S404: Obtain gravity load and inertia load.

[0104] Step S405: Based on the blade parameters of the blade to be analyzed and the geometrically accurate beam theory, a stiffness matrix, a mass matrix and a damping matrix of the blade to be analyzed are constructed.

[0105] Step S406: constructing a blade nonlinear dynamic model.

[0106] Step S407: Use Newton-Raphson time domain advancement method to solve the blade structure response to be analyzed.

[0107] Step S408: Determine whether convergence has occurred. If so, execute step S409; if not, execute step S410.

[0108] Step S409: Determine whether the simulation time has been reached, if so, execute step S413; if not, execute step S412.

[0109] Step S410: Re-determine the node displacement and rotation angle.

[0110] Step S411: updating each matrix in the blade nonlinear dynamics model.

[0111] Step S412: Update speed.

[0112] Step S413: Output the result.

[0113] Step S414: End.

[0114] 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.

[0115] 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, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0116] See attached Figure 5 , Figure 5 FIG. 1 is a schematic diagram of the main structure of an aeroelastic analysis system for a fan blade according to an embodiment of the present application. Figure 5 As shown, another aspect of the present application also provides an aeroelastic analysis system for a wind turbine blade. The aeroelastic analysis system for a wind turbine blade in the embodiment of the present invention mainly includes an acquisition module 51, an aerodynamic load determination module 52, a structural response determination module 53 and an analysis module 54. In some embodiments, one or more of the acquisition module 51, the aerodynamic load determination module 52, the structural response determination module 53 and the analysis module 54 can be combined into one module. In some embodiments, the acquisition module 51 can be configured to acquire blade parameters and wind speed data of the blade to be analyzed. The aerodynamic load determination module 52 can be configured to determine the aerodynamic load of the blade to be analyzed based on the aerodynamic model and the blade parameters and the wind speed data. The structural response determination module 53 can be configured to determine the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load of the blade to be analyzed. The analysis module 54 can be configured to perform aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed. In one embodiment, the description of the specific implementation function can be referred to the description of steps S101-step S104.

[0117] The above-mentioned aeroelastic analysis system of wind turbine blades is used to perform Figure 1 The embodiment of the aeroelastic analysis method for wind blades shown in the figure has similar technical principles, technical problems solved and technical effects produced. Those skilled in the art 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 blades can refer to the contents described in the embodiment of the aeroelastic analysis method for wind blades, which will not be repeated here.

[0118] Another aspect of the present application provides an electronic device.

[0119] See attached Figure 6 , Figure 6 exemplarily shows 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 the wind turbine blade described in any of the above embodiments is implemented.

[0120] Another aspect of the present application also provides a computer-readable storage medium.

[0121] 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 of 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.

[0122] 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 fan blades, characterized in that: The method comprises: Obtain blade parameters and wind speed data of the blade to be analyzed; Determining the aerodynamic load of the blade to be analyzed based on the aerodynamic model, the blade parameters, and the wind speed data; Determining a structural response of the blade to be analyzed based on the blade parameters and the aerodynamic loads of the blade to be analyzed; Based on the aerodynamic load and the structural response of the blade to be analyzed, an aeroelastic analysis is performed on the blade to be analyzed.

2. The aeroelastic analysis method of a fan blade according to claim 1, characterized in that: The step of determining the aerodynamic load of the blade to be analyzed based on the aerodynamic model, the blade parameters, and the wind speed data comprises: Determine an axial induction factor and a tangential induction factor based on an aerodynamic model, the blade parameters, and the wind speed data; Based on the determined axial induction factor and tangential induction factor, the aerodynamic load of the blade to be analyzed is determined.

3. The aeroelastic analysis method of a fan blade according to claim 2, characterized in that: The blade to be analyzed includes a plurality of blade elements; the determining of the axial induction factor and the tangential induction factor based on the aerodynamic model, the blade parameters, and the wind speed data includes: Determining an incoming flow velocity based on the wind speed data and the blade parameters; Determining the lift and drag on the blade element based on the incoming flow velocity; Determining the normal force and the tangential force acting on the blade element based on the lift and the drag on the blade element; Based on the normal force and tangential force acting on the blade element, determining the thrust and torque exerted on the micro-element ring at a preset distance; Based on the momentum theorem and the thrust and torque exerted on the micro-element ring at the preset distance position, determine the thrust and torque acting on the micro-element ring at the preset distance position; The axial induction factor and the tangential induction factor are determined based on the thrust and torque applied to the micro-element ring at the preset distance position and the thrust and torque acting on the micro-element ring at the preset distance position.

4. The aeroelastic analysis method of a fan blade according to claim 3, characterized in that: The step of determining the aerodynamic load of the blade to be analyzed based on the determined axial induction factor and tangential induction factor comprises: Based on the determined axial induction factor and tangential induction factor, the lift and drag acting on the blade element are integrated along the span direction of the blade to be analyzed to obtain the aerodynamic load of the blade to be analyzed.

5. The aeroelastic analysis method of a fan blade according to claim 1, characterized in that: The determining the structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load of the blade to be analyzed comprises: Obtain the gravity load and inertia load of the blade to be analyzed; Based on a pre-constructed nonlinear dynamic model of the blade, a structural response of the blade to be analyzed under an external load is determined, wherein the external load includes a gravity load, an inertia load and an aerodynamic load of the blade to be analyzed.

6. The aeroelastic analysis method of a fan blade according to claim 5, characterized in that: The blade nonlinear dynamics model is constructed by the following steps: Based on the blade parameters of the blade to be analyzed and the geometrically accurate beam theory, a stiffness matrix, a mass matrix and a damping matrix of the blade to be analyzed are constructed; Based on the stiffness matrix, mass matrix, damping matrix of the blade to be analyzed, as well as the linear momentum conservation equation, the relationship between the angular momentum change and the internal torque and the external torque, a nonlinear dynamic model of the blade is established.

7. The aeroelastic analysis method of a fan blade according to claim 5, characterized in that: The step of performing aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed comprises: Based on the structural response of the blade to be analyzed, updating the aerodynamic load of the blade to be analyzed; Determining a new structural response of the blade to be analyzed based on the updated aerodynamic load of the blade to be analyzed, and repeatedly performing the steps of updating the aerodynamic load of the blade to be analyzed and determining the new structural response of the blade to be analyzed until the updated aerodynamic load and the new structural response meet a preset convergence criterion; The aeroelasticity of the blade is analyzed based on the updated aerodynamic load and the new structural response to obtain an aeroelasticity analysis result.

8. An aeroelastic analysis system for fan blades, characterized in that: The system comprises: An acquisition module, used to acquire blade parameters and wind speed data of the blade to be analyzed; An aerodynamic load determination module, used to determine the aerodynamic load of the blade to be analyzed based on an aerodynamic model, the blade parameters, and the wind speed data; A structural response determination module, configured to determine a structural response of the blade to be analyzed based on the blade parameters and the aerodynamic load of the blade to be analyzed; An analysis module is used to perform aeroelastic analysis on the blade to be analyzed based on the aerodynamic load and the structural response of the blade to be analyzed.

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 aeroelastic analysis method for a wind turbine blade 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 aeroelastic analysis method for a wind turbine blade according to any one of claims 1 to 7.

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