Blade load assessment methods, electronic equipment and storage media

Abstract

This application relates to the field of wind turbine technology, specifically providing a blade load assessment method, electronic device, and storage medium, aiming to solve the problem of load assessment after wind turbine blades undergo elastic deformation. To this end, the blade load assessment method of this application includes: acquiring a pre-constructed aeroelastic model and a tip loss coefficient database; iteratively calculating and determining the final blade deformation based on the aeroelastic model and the tip loss coefficient database; and determining at least one of the aerodynamic load, centrifugal load, rotational load, and gravity load of the blade based on the final blade deformation. This application determines the final blade deformation through a pre-constructed aeroelastic model and tip loss coefficient database, accurately predicting the blade's deformation state, and calculating aerodynamic load, centrifugal load, rotational load, and gravity load based on the final blade deformation, providing high-precision data support for blade design and maintenance.

Description

Technical Field

[0001] This application relates to the field of wind turbine technology, specifically to a blade load assessment method, electronic equipment, and storage medium. Background Technology

[0002] Wind energy, as a clean energy source, plays a crucial role in the global energy structure transformation. However, with the increasing capacity of individual wind turbine units, the flexible deformation problem of ultra-long blades has become prominent: in the turbulent field of the near-ground boundary layer, the dynamic coupling of aerodynamic and elastic forces induces elastic deformation of the blades, leading to stall-induced vibration and flutter. This aeroelastic instability seriously affects the fatigue life of the blades and threatens the safe operation of the unit. Currently, there is an urgent need to develop a load assessment system that integrates aerodynamic-structural bidirectional coupling mechanisms and three-dimensional flow correction to solve the problem of accurate assessment of multi-physical loads in the design of ultra-long blades.

[0003] Accordingly, there is a need in the field for a new blade load assessment scheme to address the above problems. Summary of the Invention

[0004] In order to overcome the above-mentioned deficiencies, this application is made to solve or at least partially solve the technical problem of load assessment after wind turbine blades undergo elastic deformation.

[0005] In a first aspect, a blade load assessment method is provided, the method comprising: acquiring a pre-constructed aeroelastic model and a blade tip loss coefficient database; iteratively calculating and determining the final blade deformation based on the aeroelastic model and the blade tip loss coefficient database; and determining at least one of the aerodynamic load, centrifugal load, rotational load, and gravity load of the blade based on the final blade deformation.

[0006] In one technical solution of the above-mentioned blade load assessment method, determining the aerodynamic load of the blade based on the final blade deformation includes: determining the final aerodynamic force of the blade based on the final blade deformation using the aeroelastic model and the blade tip loss coefficient database; determining the axial aerodynamic force component and the tangential aerodynamic force component of the blade based on the final blade aerodynamic force component; and determining the aerodynamic load of the blade based on the axial aerodynamic force component and the tangential aerodynamic force component, wherein the aerodynamic load includes at least one of the total aerodynamic force, aerodynamic bending moment, and aerodynamic torque of the blade.

[0007] In one technical solution of the above-mentioned blade load assessment method, determining the aerodynamic load of the blade based on the axial and tangential aerodynamic components includes: obtaining the blade radius, the coordinate values ​​of the blade aerodynamic center, and the coordinate values ​​of the blade torsional center; determining the total aerodynamic force of the blade based on the blade radius, the axial and tangential aerodynamic components, wherein the total aerodynamic force includes the axial total aerodynamic force and the tangential total aerodynamic force; and / or determining the aerodynamic bending moment of the blade based on the preset reference point position, the blade radius, the axial and tangential aerodynamic components, wherein the aerodynamic bending moment includes the blade root flapping moment and the blade root oscillation moment; and / or determining the aerodynamic torque of the blade based on the coordinate values ​​of the blade aerodynamic center, the coordinate values ​​of the blade torsional center, the blade radius, the axial and tangential aerodynamic components.

[0008] In one technical solution of the above-mentioned blade load assessment method, determining at least one of centrifugal load, rotational load, and gravity load based on the final blade deformation includes: updating blade attribute parameters based on the final blade deformation; and determining at least one of centrifugal load, rotational load, and gravity load based on the updated blade attribute parameters.

[0009] In one technical solution of the above-mentioned blade load assessment method, the updated blade attribute parameters include the updated equivalent density of the wind turbine blade section, the equivalent area of ​​the wind turbine blade section, and the blade coordinate value; the step of determining the centrifugal load based on the updated blade attribute parameters includes: obtaining the wind turbine rotation speed; determining the lateral centrifugal force and the radial centrifugal force based on the wind turbine rotation speed, the equivalent density of the wind turbine blade section, the equivalent area of ​​the wind turbine blade section, and the blade coordinate value; and determining the centrifugal load of the blade based on the lateral centrifugal force and the radial centrifugal force, wherein the centrifugal load includes at least one of centrifugal tension, centrifugal shear force, centrifugal bending moment, and centrifugal torque, wherein the centrifugal bending moment includes the lateral centrifugal bending moment and the radial centrifugal bending moment.

[0010] In one technical solution of the above-mentioned blade load assessment method, the updated blade attribute parameters include the height of the blade's preset position from the hub center and the rotor radius; the step of determining the blade's rotational load based on the updated blade attribute parameters includes: acquiring the wind turbine speed, yaw speed, and linear mass density at the blade's radial position; and determining the blade's rotational load based on the wind turbine speed, the yaw speed, the linear mass density at the blade's radial position, the height of the blade's preset position from the hub center, and the rotor radius, wherein the rotational load includes the blade root bending moment.

[0011] In one technical solution of the above-mentioned blade load assessment method, the updated blade attribute parameters include the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate value; determining the gravity load of the blade based on the updated blade attribute parameters includes: obtaining the gravitational acceleration and the blade azimuth angle; determining the gravity distribution load in the blade flapping direction and the gravity distribution load in the blade oscillation direction based on the gravitational acceleration, the blade azimuth angle, the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate value; determining the gravity load of the blade based on the gravity distribution load in the blade flapping direction and the gravity distribution load in the blade oscillation direction, wherein the gravity load includes at least one of gravity pressure, gravity shear force, gravity bending moment, and gravity torque.

[0012] In one technical solution of the aforementioned blade load assessment method, the aeroelastic model includes an aerodynamic model constructed based on blade element momentum theory and a structural model constructed based on geometrically precise beam theory; the blade tip loss coefficient database includes multiple sets of deformation amplitudes and corresponding blade tip loss coefficients; the iterative calculation to determine the final blade deformation based on the aeroelastic model and the blade tip loss coefficient database includes: determining the initial aerodynamic force of the blade in its undeformed state based on the aerodynamic model; inputting the initial aerodynamic force into the structural model to determine the initial blade deformation; obtaining the blade tip loss coefficient corresponding to the initial blade deformation through linear interpolation based on the initial blade deformation and the blade tip loss coefficient database; updating the blade aerodynamic force based on the blade tip loss coefficient corresponding to the initial blade deformation; inputting the updated blade aerodynamic force into the structural model to determine the updated blade deformation; determining whether the difference between the updated blade deformation and the previous blade deformation is greater than or equal to a preset threshold; if so, continuing to update the blade deformation until the difference between the updated blade deformation and the previous blade deformation is less than the preset threshold; otherwise, using the updated blade deformation as the final blade deformation.

[0013] In a second aspect, an electronic device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program, which, when executed by the at least one processor, implements the method described in any of the above-described blade load assessment methods.

[0014] In a third aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, the program codes being adapted to be loaded and run by a processor to perform the method described in any of the above-described blade load assessment methods.

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

[0016] The blade load assessment method provided in this application includes: acquiring a pre-constructed aeroelastic model and a tip loss coefficient database; iteratively calculating and determining the final blade deformation based on the aeroelastic model and the tip loss coefficient database; and determining at least one of the aerodynamic load, centrifugal load, rotational load, and gravity load of the blade based on the final blade deformation. This application performs aerodynamic coupling analysis on the blade based on the aeroelastic model and the tip loss coefficient database to obtain the final blade deformation, and accurately calculates the aerodynamic load, centrifugal load, rotational load, and gravity load based on the final blade deformation. This provides high-precision data support for blade design and operation and maintenance, effectively ensuring the safety of wind turbine blades during operation and reducing personal and economic losses. Attached Figure Description

[0017] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Wherein:

[0018] Figure 1 This is a schematic flowchart of the main steps of a blade load assessment method according to an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of velocity composition and aerodynamic forces under leaf element rotation conditions according to an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of a blade deformation assessment process according to an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the blade azimuth angle according to an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the main structure of an electronic device according to an embodiment of this application.

[0023] Figure label:

[0024] 11: Memory; 12: Processor. Detailed Implementation

[0025] Some embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0026] In the description of this application, "module" and "processor" can include hardware, software, or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and may also include software components, such as program code, or a combination of software and hardware. A processor can be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. Computer-readable storage media includes any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, 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 terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0027] Wind energy, as a clean energy source, plays a crucial role in the global energy structure transformation. However, with the increasing capacity of individual wind turbine units, the flexible deformation problem of ultra-long blades has become prominent: in the turbulent field of the near-ground boundary layer, the dynamic coupling of aerodynamic and elastic forces can induce elastic deformation of the blades, leading to stall-induced vibration and flutter. This aeroelastic instability seriously affects the fatigue life of the blades and threatens the safe operation of the unit. Currently, there is an urgent need to develop a high-precision load assessment system that integrates aerodynamic-structural bidirectional coupling mechanisms and three-dimensional flow correction to solve the multi-physics load assessment problem in the design of ultra-long blades.

[0028] Therefore, the blade load assessment method provided in this application includes: acquiring a pre-constructed aeroelastic model and a blade tip loss coefficient database; iteratively calculating and determining the final blade deformation based on the aeroelastic model and the blade tip loss coefficient database; and determining at least one of the aerodynamic load, centrifugal load, rotational load, and gravity load of the blade based on the final blade deformation. This application performs aerodynamic coupling analysis on the blade based on the aeroelastic model and the blade tip loss coefficient database to determine the final blade deformation, and calculates the aerodynamic load, centrifugal load, rotational load, and gravity load based on the final blade deformation, providing high-precision data support for blade design and operation and maintenance, effectively ensuring the safety of wind turbine blades during operation, and reducing personal and economic losses.

[0029] See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of a blade load assessment method according to an embodiment of this application. Figure 1As shown, the blade load evaluation method in this application embodiment mainly includes the following steps S101 to S103.

[0030] Step S101: Obtain the pre-built aeroelastic model and blade tip loss coefficient database.

[0031] In this embodiment, the aeroelastic model includes an aerodynamic model and a structural model, and the blade tip loss coefficient database includes multiple sets of blade deformation amplitudes and corresponding blade tip loss coefficients.

[0032] Step S102: Based on the aeroelastic model and the blade tip loss coefficient database, iteratively calculate and determine the final blade deformation.

[0033] Step S103: Based on the final deformation of the blade, determine at least one of the aerodynamic load, centrifugal load, rotational load and gravity load of the blade.

[0034] In this embodiment, based on the final deformation of the blades, the aerodynamic loads generated by the airflow, the centrifugal loads generated by the rotational effect, the rotational loads caused by changes in wind direction or the actions of the control system, and the gravitational loads of the wind turbine in the gravitational field are evaluated.

[0035] Based on the methods described in steps S101 to S103 above, this application performs aerodynamic coupling analysis based on the aeroelastic model and the blade tip loss coefficient database to determine the final blade deformation. On this basis, it evaluates the various loads borne by the blade, such as aerodynamic loads, centrifugal loads, rotational loads, and gravity loads, providing high-precision data support for blade design. Through accurate load calculation and analysis, it can also detect potential safety hazards of blades or wind turbines in advance and take corresponding preventive measures to improve the overall operational safety and economy of wind turbines.

[0036] The following provides further explanation of steps S101 to S103.

[0037] For step S101, obtain the pre-built aeroelastic model and blade tip loss coefficient database.

[0038] Specifically, the aeroelastic model includes an aerodynamic model based on leaf element momentum theory (BEM) and a structural model based on geometrically precise beam theory (GEBT).

[0039] When constructing the aerodynamic model based on blade element momentum theory (BEM), the following assumptions are made: the wind turbine consists of an infinite number of blades, and the wind turbine can be simplified as a planar blade disk; the incoming flow is uniform and steady, i.e., air compressibility is not considered; the radial blade elements are independent of each other, there is no interaction between them, and the radial flow of flow field particles is ignored; the influence of wake-induced velocity is ignored.

[0040] Velocity composition relationship and aerodynamic forces under leaf element rotation conditions, such as Figure 2 As shown, the velocity composition relationship is expressed as:

[0041]

[0042] In the formula, φ is the inflow angle; V is the free flow velocity; Ω is the rotor speed; r is the radius at the blade position where the blade element is located; a is the axial induction factor; and b is the tangential induction factor.

[0043] The relationship between the inflow angle φ, the angle of attack α, and the pitch angle β is as follows:

[0044] α=φ-β

[0045] According to the theory of leaf elements, the lift force dF on a leaf element infinitesimal element is... l and resistance dF d The expression is:

[0046]

[0047] Where ρ is the air density; W is the composite relative wind speed at the location of the leaf element; C is the chord length; C L C is the airfoil lift coefficient; D This represents the airfoil drag coefficient.

[0048] Decomposing the lift and drag forces acting on the blade element into the plane of rotation of the wind turbine and in directions perpendicular to the plane of rotation, we obtain the normal force F acting on the blade element. n and tangential force F t .

[0049]

[0050] Among them, C n C is the normal force coefficient. t The tangential force coefficient can be expressed as:

[0051] C n =C L cosφ+C D sinφ

[0052] C t =C L sinφ-C D cosφ

[0053] The thrust and torque of the infinitesimal ring located at a distance r from the center of the wind turbine can be calculated using the following formula:

[0054]

[0055] In the formula, B represents the number of blades.

[0056] According to the momentum theorem and Prandtl's tip loss model, the thrust and torque acting on a micro-element ring of width dr at the radius r of the wind turbine are:

[0057] dT 动量 =4πρV 2 (1-a)arFdr

[0058] dM 动量 =4πρVΩ(1-a)br 3 Fdr

[0059] Where F is the tip loss correction factor, expressed as:

[0060] Using dT 叶素 =dT 动量 ,dM 叶素 =dM 动量 Thus, the axial induction factor and tangential induction factor can be obtained as follows:

[0061]

[0062] The steps for constructing a structural model based on Geometrically Precise Beam Theory (GEBT) include:

[0063] The nonlinear motion control equations of geometrically precise beam theory are as follows:

[0064]

[0065] In the formula, h and g are the linear momentum and angular momentum in the inertial coordinate system, respectively; F is the cross-sectional force of the beam; M is the moment of the beam; u is the linear displacement of a point on the reference line; x0 is the position vector of the point along the beam reference line; f and m are the distributed force and moment applied to the beam structure; the symbol F' represents the derivative of the relative time beam x1. Represents the derivative with respect to time. The tilde operator defines a skew-symmetric tensor corresponding to a given vector.

[0066] The constitutive equations correlate velocity with momentum, and one-dimensional strain measurements with cross-sectional results:

[0067]

[0068] Where M and C are the 6×6 cross-sectional mass matrix and stiffness matrix, respectively; 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 Vector a is associated with a second-order tensor A, whose components are defined as follows:

[0069]

[0070] One-dimensional strain ε and curvature k are defined as follows:

[0071]

[0072] Where, k = axial[(RR0)'(RR0)] T ] is the cross-sectional curvature vector decomposed on the inertial basis; R is the rotation tensor of the current configuration, describing the rotation of the cross-section about the inertial axis; x'0 is the derivative of the position vector of the beam in the initial configuration; u' is the derivative of the displacement vector; R0 is the initial rotation tensor; l1 is the unit vector along the x1 direction in the inertial basis.

[0073] A CFD simulation method was used to construct a blade tip loss coefficient database. Specifically, for preset blade deformation ranges, such as 0%, 5%, 10%, 15%, and 20%, a corresponding blade geometric model was generated. CFD simulation calculations were performed on each blade geometric model to obtain aerodynamic data. The aerodynamic forces of the deformed blade were compared with those of the undeformed blade to obtain an additional blade tip loss coefficient. An additional blade tip loss coefficient F associated with the preset deformation range was defined. extra Using spline interpolation, the tip loss coefficient F under arbitrary deformation amplitude is obtained by interpolation based on data obtained from CFD simulation. extra A tip loss coefficient database containing multiple sets of deformation amplitudes and corresponding tip loss coefficients was constructed.

[0074] Regarding step S102, in one embodiment, the aeroelastic model includes an aerodynamic model constructed based on blade element momentum theory and a structural model constructed based on geometrically precise beam theory; the blade tip loss coefficient database includes multiple sets of deformation amplitudes and corresponding blade tip loss coefficients; the iterative calculation to determine the final blade deformation based on the aeroelastic model and the blade tip loss coefficient database includes: determining the initial aerodynamic force of the blade in its undeformed state based on the aerodynamic model; inputting the initial aerodynamic force into the structural model to determine the initial blade deformation; obtaining the blade tip loss coefficient corresponding to the initial blade deformation through linear interpolation based on the initial blade deformation and the blade tip loss coefficient database; updating the blade aerodynamic force based on the blade tip loss coefficient corresponding to the initial blade deformation; inputting the updated blade aerodynamic force into the structural model to determine the updated blade deformation; determining whether the difference between the updated blade deformation and the previous blade deformation is greater than or equal to a preset threshold; if so, continuing to update the blade deformation until the difference between the updated blade deformation and the previous blade deformation is less than the preset threshold; otherwise, using the updated blade deformation as the final blade deformation.

[0075] The steps for determining the final deformation of the blade are as follows: Figure 2 As shown.

[0076] Specifically, the initial aerodynamic force F1 of the blade in its undeformed state is calculated using an initial aerodynamic model. This initial aerodynamic force F1 is then converted into distributed forces and moments applied to the beam structure and input into the structural model to obtain the initial blade deformation w1 under the initial aerodynamic force. Deformation refers to the blade's deformation deflection. Then, based on the initial blade deformation w1 and combined with an additional tip loss coefficient database, the tip loss coefficient F corresponding to the initial deformation is interpolated to obtain the value. extra And based on the tip loss coefficient F corresponding to the initial deformation. extra The blade aerodynamic force is updated to F2. This updated aerodynamic force F2 is then re-input into the structural model to obtain the updated blade deformation w2. The updated blade deformation w2 is compared with the original blade deformation w2. If the difference exceeds a preset threshold, the iteration continues, updating the blade deformation w2 until the difference between the updated and original blade deformation w2 is less than the preset threshold. Through iteration, the final blade deformation w2 under actual operating conditions is obtained.

[0077] Regarding step S103, in one embodiment, determining the aerodynamic load of the blade based on the final blade deformation includes: determining the final aerodynamic force of the blade based on the final blade deformation using the aeroelastic model and the tip loss coefficient database; determining the axial aerodynamic force component and the tangential aerodynamic force component of the blade based on the final blade aerodynamic force component; and determining the aerodynamic load of the blade based on the axial aerodynamic force component and the tangential aerodynamic force component of the blade, wherein the aerodynamic load includes at least one of the total aerodynamic force, aerodynamic bending moment, and aerodynamic torque of the blade.

[0078] Specifically, based on the final blade deformation and combined with a tip loss coefficient database, the tip loss coefficient corresponding to the final blade deformation is determined by interpolation. Then, the tip loss correction factor in the aerodynamic model is corrected based on the tip loss coefficient corresponding to the final blade deformation, thus obtaining the final aerodynamic force of the blade after correcting for tip loss. Specifically: considering the influence of blade deformation, the airfoil section at the blade tip deviates from the wind turbine plane, causing a change in the projected area during calculation. The angle between the tangent of the blade at a distance r from the blade root after deformation and the original blade is set as γ. The aerodynamic force dFa caused by the synthesized relative wind speed W acting on a blade element of length dr after deformation can be decomposed into a normal force dF. n and tangential force dF t Then the expressions for the normal force and tangential force of the deformed section are:

[0079]

[0080] The thrust acting on the circular ring dr in the wind turbine plane is expressed as:

[0081]

[0082] The torque acting on the circular ring dr in the wind turbine plane is expressed as:

[0083]

[0084] The total thrust of the wind turbine is:

[0085]

[0086] The total torque of the wind turbine is:

[0087]

[0088] Using the leaf element momentum theory and the Gauss-Seidel iterative method, the final inflow angle φ and lift coefficient C are obtained. L and drag coefficient C D Specifically:

[0089] The axial induction factor a and the tangential induction factor b are solved iteratively, with the following iterative steps:

[0090] Step S1: Assume that the initial values ​​of the axial induction factor a and the tangential induction factor b are 0.

[0091] Step S2: Based on the initial values ​​of the axial induction factor a and the tangential induction factor b, calculate the inflow angle φ:

[0092]

[0093] Step S3: Calculate the angle of attack α based on the inflow angle φ.

[0094] Step S4: Obtain the lift coefficient C of the blade element based on the airfoil aerodynamic characteristic curve. L and drag coefficient C D .

[0095] Step S5: Lift coefficient C based on leaf element L and drag coefficient C D Calculate the normal force coefficient C of the leaf element. n and tangential force coefficient C t .

[0096] Step S6: Normal force coefficient C based on leaf element n and tangential force coefficient C t Calculate the new values ​​of axial induction factor a and tangential induction factor b:

[0097]

[0098] In the formula, σ is the realism, which refers to the ratio of the blade cross-sectional area to the swept area of ​​the wind turbine, σ=BC / (2πr).

[0099] Step S7: Calculate the difference between the new values ​​of the axial induction factor a and the tangential induction factor b and the initial values. Determine whether the difference is less than the preset error threshold (generally 0.001). If so, proceed to step S8; otherwise, use the new values ​​of the axial induction factor a and the tangential induction factor b as the initial values, return to step S2, and continue iterating.

[0100] Step S8: Iteration terminates.

[0101] Based on the determined axial induction factor a and tangential induction factor b, the inflow angle and angle of attack are calculated to obtain the lift coefficient C. L and drag coefficient C D .

[0102] Based on the determined lift coefficient C L and drag coefficient C D Considering the final deformation of the blade, the normal and tangential forces acting on the blade element are calculated. These forces constitute the final aerodynamic forces of the blade, and the calculation formulas are as follows:

[0103]

[0104] The normal and tangential forces acting on the blade element are decomposed into axial and tangential components to determine the axial aerodynamic component q of the blade. x and tangential aerodynamic component q y :

[0105]

[0106] Then, based on the axial aerodynamic component q x and tangential aerodynamic component q y The total aerodynamic force, aerodynamic bending moment, and aerodynamic torque of the blade are determined.

[0107] In one embodiment, determining the aerodynamic load of the blade based on the axial and tangential aerodynamic components includes: acquiring the blade radius, the coordinate values ​​of the blade aerodynamic center, and the coordinate values ​​of the blade torsional center; determining the total aerodynamic force of the blade based on the blade radius, the axial and tangential aerodynamic components, the total aerodynamic force including the axial total aerodynamic force and the tangential total aerodynamic force; and / or determining the aerodynamic bending moment of the blade based on the position of a preset reference point, the blade radius, the axial and tangential aerodynamic components, the aerodynamic bending moment including the blade root flapping moment and the blade root oscillation moment; and / or determining the aerodynamic torque of the blade based on the coordinate values ​​of the blade aerodynamic center, the coordinate values ​​of the blade torsional center, the blade radius, the axial and tangential aerodynamic components.

[0108] Specifically, based on the blade radius R and the axial aerodynamic component q of the blade... x and tangential aerodynamic component q y The total aerodynamic force of the blade is determined using the following formula:

[0109]

[0110] That is, the normal and tangential forces (i.e., axial and tangential aerodynamic components) acting on each leaf element are integrated along the span of the blade (from the root to the tip) to obtain the total axial aerodynamic force Q. x and tangential total aerodynamic force Q y .

[0111] Based on the preset reference point position, blade radius, and the axial and tangential aerodynamic components of the blade, the aerodynamic bending moment of the blade is determined using the following formula:

[0112]

[0113] In the formula, M x For the direction torque of leaf root waving, M y The torque in the direction of blade root oscillation is given by r0, which is the preset reference point position (usually the distance from the blade root to the rotation center), and r is the distance from the current blade element to the blade root. (r0-r) refers to the radial distance from the rotation center to the current blade element position.

[0114] Based on the coordinates of the blade's aerodynamic center, the coordinates of the blade's torsional center, the blade radius, and the axial and tangential aerodynamic components of the blade, the aerodynamic torque of the blade is determined using the following formula:

[0115]

[0116] In the formula, M ka R is the aerodynamic torque; (xp, yp) is the coordinate value of the aerodynamic center of the blade, which refers to the coordinate value of the aerodynamic center of the blade in the overall cross-sectional coordinate system; (xc, yc) is the coordinate value of the torsional center of the blade, which refers to the coordinate value of the torsional center of the blade in the overall cross-sectional coordinate system.

[0117] In one embodiment, determining at least one of centrifugal load, rotational load, and gravity load based on the final blade deformation includes: updating blade attribute parameters based on the final blade deformation; and determining at least one of centrifugal load, rotational load, and gravity load based on the updated blade attribute parameters.

[0118] Specifically, blade deformation can affect its property parameters, which can include cross-sectional properties and geometric layout parameters such as blade radius, cross-sectional equivalent density, and cross-sectional equivalent area. Changes in these parameters directly impact the accuracy of load calculations. Therefore, it is necessary to determine the centrifugal load, rotational load, and gravity load based on the updated blade property parameters to ensure accurate load assessment.

[0119] In one embodiment, the updated blade attribute parameters include the updated equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate values; determining the centrifugal load based on the updated blade attribute parameters includes: obtaining the wind turbine rotational speed; determining the lateral centrifugal force and the radial centrifugal force based on the wind turbine rotational speed, the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate values; determining the centrifugal load of the blade based on the lateral centrifugal force and the radial centrifugal force, wherein the centrifugal load includes at least one of centrifugal tension, centrifugal shear force, centrifugal bending moment, and centrifugal torque, wherein the centrifugal bending moment includes the lateral centrifugal bending moment and the radial centrifugal bending moment.

[0120] Specifically, lateral centrifugal force refers to the force exerted by the centrifugal force on the blade section due to the deviation of the center of gravity from the axis of rotation (y). G =0) caused by the transverse (flailing direction) centrifugal force. The radial centrifugal force is the centrifugal force along the plane of rotation (flailing direction) caused by the blade rotation radius (r).

[0121] Based on the wind turbine rotational speed, the equivalent density of the wind turbine blade cross-section, the equivalent area of ​​the wind turbine blade cross-section, and the blade coordinate values, the lateral centrifugal force and radial centrifugal force per unit length are determined using the following formulas:

[0122] q yp =ρ0Ω 2 F0y G

[0123] q RP =ρ0Ω 2 F0r

[0124] In the formula, q yp For the lateral centrifugal force, q RP The radial centrifugal force is ρ0, the equivalent density of the wind turbine blade section is Ω, the wind turbine rotational speed is F0, and the equivalent area of ​​the wind turbine blade section is y. G is the coordinate value of the blade in the global coordinate system; r is the distance from the leaf root to the cross-section.

[0125] Integrating the radial centrifugal force along the current cross-section r of the blade to the blade tip yields the centrifugal tension P. RP The calculation formula is as follows:

[0126]

[0127] In the formula, r1 is the integral variable (ranging from the current section r to the blade tip R), and R refers to the blade length.

[0128] Integrating the transverse centrifugal force along the current cross section r of the blade to the blade tip yields the centrifugal shear force Q. RP The calculation formula is as follows:

[0129]

[0130] The transverse centrifugal bending moment M is determined based on the transverse centrifugal force and the radial centrifugal force, respectively. xp and radial centrifugal bending moment M yp The calculation formula is as follows:

[0131]

[0132] In the formula, x G (r) represents the coordinate of the centroid at the current section r in the x-direction, x G (r1) represents the coordinates of the centroid at the integration position r1 in the x-direction, and y-direction... G (r) represents the coordinate of section r in the y-direction, y G (r1) is the coordinate of the centroid at section r1 in the y direction.

[0133] The centrifugal torque M is determined based on the lateral centrifugal force and the radial centrifugal force. kp The calculation formula is as follows:

[0134]

[0135] In one embodiment, the updated blade attribute parameters include the height of the blade's preset position from the hub center and the rotor radius; determining the blade's rotational load based on the updated blade attribute parameters includes: acquiring the wind turbine rotational speed, yaw speed, and linear mass density at the blade's radial position; determining the blade's rotational load based on the wind turbine rotational speed, the yaw speed, the linear mass density at the blade's radial position, the height of the blade's preset position from the hub center, and the rotor radius, wherein the rotational load includes the blade root bending moment.

[0136] Specifically, when a wind turbine yaws, the blades are subjected to a rotational load perpendicular to the plane of rotation. Taking the blade's predetermined position (point A) as the research object, assuming the rotor yaws clockwise, and considering the inertial forces acting on the blades, the expression for the blade root bending moment can be obtained as follows:

[0137]

[0138] In the formula, M YR is the blade root bending moment; R is the rotor radius; Ω is the wind turbine rotational speed; Ωˊ is the yaw speed; z is the height of the blade at the preset position (point A) from the hub center; r is the integral variable, referring to the distance from the current blade element to the blade root; m(r) is the linear mass density (kg / m) at the radial position r of the blade; ξ is the angle between the preset position of the blade (point A) and the direction perpendicular to the ground; I B The root moment of inertia (kg·m) 2 The contribution of blade mass distribution to the rotation effect is expressed as:

[0139]

[0140] In one embodiment, the updated blade attribute parameters include the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate value; determining the gravity load of the blade based on the updated blade attribute parameters includes: obtaining gravitational acceleration and blade azimuth angle; determining the gravity distribution load in the blade flapping direction and the gravity distribution load in the blade oscillation direction based on the gravitational acceleration, the blade azimuth angle, the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate value; determining the gravity load of the blade based on the gravity distribution load in the blade flapping direction and the gravity distribution load in the blade oscillation direction, wherein the gravity load includes at least one of gravity pressure, gravity shear force, gravity bending moment, and gravity torque.

[0141] Specifically, the blade azimuth angle is as follows: Figure 4 As shown, based on gravitational acceleration, blade azimuth angle, equivalent density of wind turbine blade cross-section, equivalent area of ​​wind turbine blade cross-section, and blade coordinate values, the gravitational load distributed in the blade flapping direction and the gravitational load distributed in the blade oscillation direction are determined respectively. The calculation formulas are as follows:

[0142]

[0143] q yw =-ρ0f0g cosψ

[0144] q Rw =-ρ0F0g sinψ

[0145] In the formula, q yw q represents the gravity load distributed in the direction of blade flapping. Rw The load distributed by gravity in the direction of blade oscillation is given by ρ0, where ρ is the equivalent density of the wind turbine blade cross section; F0 is the equivalent area of ​​the wind turbine blade cross section; ρ i The density of each section; F i Ψ represents the cross-sectional area of ​​each part; g represents the acceleration due to gravity; and Ψ represents the blade azimuth angle.

[0146] Gravitational pressure, also known as gravitational tension, is the pressure or tension generated by gravity along its axis. The gravitational pressure P is determined by integrating the distributed gravitational load along the current section to the blade tip in the direction of blade wobbling. Rw The calculation formula is as follows:

[0147]

[0148] In the formula, r1 is the integration variable, representing the radial position of any point on the blade; r is the lower limit of integration (current section); R is the blade length, and during integration calculation, all positions (variables) from r to R are traversed; sinΨ refers to the direction of projection onto the structural axis (radial).

[0149] For the gravity-distributed load in the blade flapping direction, integrate from the current section to the blade tip to determine the gravity shear force Q. yw The calculation formula is as follows:

[0150]

[0151] In the formula, cosΨ refers to the projection onto the transverse direction perpendicular to the axis, i.e., the shearing effect caused by gravity.

[0152] Based on the distance between the radial position r1 of any point on the blade and the current section r, and the gravity distribution load in the blade flapping direction, determine the gravity bending moment M. xw The calculation formula is as follows:

[0153]

[0154] In the formula, cosΨ indicates that the bending moment is generated by the transverse component (cos).

[0155] Based on the coordinate difference between the transverse coordinate of the centroid of the infinitesimal segment and the transverse coordinate of the reference axis, and the gravity distribution load, the gravitational torque M is determined. kw The calculation formula is as follows:

[0156]

[0157] In the formula, X G X is the horizontal coordinate of the centroid of the infinitesimal segment; C is the lateral coordinate of the reference axis (e.g., the center of rotation); r1 is the integration variable, representing the radial position of any point on the blade; r is the lower limit of integration (current section), which is a fixed value; R is the blade length.

[0158] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effect of this application, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted solutions are equivalent to the technical solutions described in this application and therefore will also fall within the protection scope of this application.

[0159] Those skilled in the art will understand that all or part of the processes in the method of the above-described embodiment can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include any entity or device capable of carrying the computer program code, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0160] Another aspect of this application provides an electronic device.

[0161] In one embodiment of an electronic device according to this application, the electronic device may include at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program, which, when executed by the at least one processor, implements the method described in any of the above embodiments. The electronic device described in this application may include driving equipment, intelligent vehicles, robots, and other devices. See appendix. Figure 5 , Figure 5 The image exemplarily illustrates a communication connection between memory 11 and processor 12 via a bus.

[0162] In some embodiments of this application, the electronic device may further include at least one sensor for sensing information. The sensor is communicatively connected to any type of processor mentioned in this application. The electronic device described in this application may be, but is not limited to, mobile phones, tablets, desktop computers, laptops, handheld computers, notebook computers, in-vehicle devices, ultra-mobile personal computers (UMPCs), netbooks, personal digital assistants (PDAs), augmented reality (AR) devices, virtual reality (VR) devices, etc., and this application does not limit the scope of the embodiments.

[0163] Another aspect of this application provides a computer-readable storage medium.

[0164] In one embodiment of a computer-readable storage medium according to this application, the computer-readable storage medium can be configured to store a program that performs the blade load evaluation method of the above-described method embodiments. This program can be loaded and run by a processor to implement the blade load evaluation method. For ease of explanation, only the parts related to the embodiments of this application are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of this application. The computer-readable storage medium can be a storage device comprising various electronic devices. Optionally, in the embodiments of this application, the computer-readable storage medium is a non-transitory computer-readable storage medium.

[0165] The technical solution of this application has been described above with reference to one embodiment shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this 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 all fall within the scope of protection of this application.

Claims

1. A method for evaluating blade load, characterized in that, The method includes: Obtain a pre-constructed aeroelastic model and a blade tip loss coefficient database; wherein, the aeroelastic model includes an aerodynamic model constructed based on blade element momentum theory and a structural model constructed based on geometrically accurate beam theory; the blade tip loss coefficient database includes multiple sets of deformation amplitudes and corresponding blade tip loss coefficients; Based on the aeroelastic model and the blade tip loss coefficient database, the final blade deformation is determined by iterative calculation. Based on the final deformation of the blade, determine at least one of the aerodynamic load, centrifugal load, rotational load, and gravity load of the blade; The step of iteratively calculating and determining the final blade deformation based on the aeroelastic model and the tip loss coefficient database includes: determining the initial aerodynamic force of the blade in its undeformed state based on the aerodynamic model; inputting the initial aerodynamic force into the structural model to determine the initial blade deformation; obtaining the tip loss coefficient corresponding to the initial blade deformation through linear interpolation based on the initial blade deformation and the tip loss coefficient database; updating the blade aerodynamic force based on the tip loss coefficient corresponding to the initial blade deformation; inputting the updated blade aerodynamic force into the structural model to determine the updated blade deformation; determining whether the difference between the updated blade deformation and the previous blade deformation is greater than or equal to a preset threshold; if so, continuing to update the blade deformation until the difference between the updated blade deformation and the previous blade deformation is less than the preset threshold; otherwise, using the updated blade deformation as the final blade deformation.

2. The blade load assessment method according to claim 1, characterized in that, The determination of the aerodynamic load on the blade based on the final deformation of the blade includes: Based on the final blade deformation, the final aerodynamic force of the blade is determined using the aeroelastic model and the blade tip loss coefficient database. Based on the final aerodynamic force of the blade, the axial aerodynamic force component and the tangential aerodynamic force component of the blade are determined. Based on the axial and tangential aerodynamic components of the blade, the aerodynamic load of the blade is determined, and the aerodynamic load includes at least one of the total aerodynamic force, aerodynamic bending moment, and aerodynamic torque of the blade.

3. The blade load assessment method according to claim 2, characterized in that, The determination of the aerodynamic load on the blade based on the axial and tangential aerodynamic components includes: Obtain the blade radius, the coordinates of the blade aerodynamic center, and the blade torsion center; Based on the blade radius, the axial aerodynamic components, and the tangential aerodynamic components of the blade, the total aerodynamic force of the blade is determined, the total aerodynamic force including the axial total aerodynamic force and the tangential total aerodynamic force; and / or, Based on the preset reference point position, the blade radius, and the axial and tangential aerodynamic components of the blade, the aerodynamic bending moment of the blade is determined, wherein the aerodynamic bending moment includes the blade root flapping moment and the blade root flaring moment; and / or, The aerodynamic torque of the blade is determined based on the coordinates of the blade's aerodynamic center, the blade's torsional center, the blade's radius, and the blade's axial and tangential aerodynamic components.

4. The blade load assessment method according to claim 1, characterized in that, The determination of at least one of centrifugal load, rotational load, and gravity load based on the final deformation of the blade includes: Update the blade attribute parameters based on the final blade deformation. Based on the updated blade property parameters, determine at least one of the centrifugal load, rotational load, and gravity load.

5. The blade load assessment method according to claim 4, characterized in that, The updated blade attribute parameters include the updated wind turbine blade cross-sectional equivalent density, wind turbine blade cross-sectional equivalent area, and blade coordinate values; The determination of centrifugal force load based on the updated blade attribute parameters includes: Obtain the wind turbine rotation speed; Based on the wind turbine rotation speed, the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate value, the lateral centrifugal force and the radial centrifugal force are determined. Based on the lateral centrifugal force and the radial centrifugal force, the centrifugal load of the blade is determined. The centrifugal load includes at least one of centrifugal tension, centrifugal shear force, centrifugal bending moment, and centrifugal torque, wherein the centrifugal bending moment includes lateral centrifugal bending moment and radial centrifugal bending moment.

6. The blade load assessment method according to claim 4, characterized in that, The updated blade attribute parameters include the height of the preset blade position from the hub center and the rotor radius; The determination of the rotational load of the blade based on the updated blade attribute parameters includes: Obtain the linear mass density of wind turbine rotational speed, yaw speed, and blade radial position; Based on the wind turbine rotational speed, the yaw speed, the linear mass density of the blade radial position, the height of the blade's preset position from the hub center, and the wind turbine radius, the rotational load of the blade is determined, and the rotational load includes the blade root bending moment.

7. The blade load assessment method according to claim 4, characterized in that, The updated blade attribute parameters include the wind turbine blade cross-sectional equivalent density, the wind turbine blade cross-sectional equivalent area, and the blade coordinate values; The determination of the blade's gravity load based on the updated blade attribute parameters includes: Obtain gravitational acceleration and blade azimuth angle; Based on the gravitational acceleration, the blade azimuth angle, the equivalent density of the wind turbine blade cross section, the equivalent area of ​​the wind turbine blade cross section, and the blade coordinate value, the gravitational load distribution in the blade flapping direction and the gravitational load distribution in the blade oscillation direction are determined respectively. The gravity load of the blade is determined based on the gravity distribution load in the blade flapping direction and the gravity distribution load in the blade oscillation direction. The gravity load includes at least one of gravity pressure, gravity shear force, gravity bending moment and gravity torque.

8. An electronic device comprising at least one processor and at least one memory, said memory being adapted to store a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to perform the blade load evaluation method according to any one of claims 1 to 7.

9. A computer-readable storage medium storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by a processor to perform the blade load evaluation method according to any one of claims 1 to 7.

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