Blade deformation evaluation method, electronic equipment and storage medium

Abstract

The invention relates to the technical field of wind turbine generators, particularly provides a blade deformation evaluation method, electronic equipment and a storage medium, and aims to solve the problems of complex calculation and limited precision of an existing blade deformation evaluation method. Therefore, the blade deformation evaluation method comprises the steps that an aeroelastic model considering blade tip loss is constructed, and the aeroelastic model comprises a pneumatic model and a structural model; constructing a blade tip loss coefficient database; based on the aeroelastic model, initial aerodynamic force and initial blade deformation corresponding to the initial aerodynamic force are determined; based on the initial aerodynamic force, the initial blade deformation amount and the blade tip loss coefficient database, the corrected aerodynamic force is determined; and based on the initial aerodynamic force and the corrected aerodynamic force, the deformation state of the blade is evaluated. Through reasonable modeling and analysis, the deformation state of the blade under different wind speed conditions can be accurately identified, and the design and operation parameters of the blade are optimized.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbines, and in particular to a blade deformation assessment method, electronic equipment, and storage medium. Background Art

[0002] With the development trend of larger wind turbines, the aspect ratio of blades has increased significantly, and their structural flexibility has also increased accordingly. The flexibility of blades makes them prone to large bending and torsional deformation under strong wind and turbulent conditions. This dynamic response (including bending, torsion and vibration) not only directly affects the aerodynamic efficiency of the blades, but also reduces their structural stability and service life. In addition, deformation may cause structural fatigue or even failure, leading to serious safety hazards and economic losses. Therefore, how to accurately evaluate the deformation characteristics of flexible blades under different operating conditions has become a key issue in the design and optimization of wind turbines. At present, there are some deformation assessment methods for flexible blades, but these methods are often computationally complex and have limited accuracy, making them difficult to promote and apply in actual engineering.

[0003] Accordingly, a new blade deformation assessment solution is needed in the art 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 problems of the existing blade deformation assessment method, such as complex calculation and limited accuracy.

[0005] In a first aspect, a blade deformation assessment method is provided, the method comprising: constructing an aeroelastic model that takes tip loss into consideration, the aeroelastic model comprising an aerodynamic model and a structural model; constructing a tip loss coefficient database; determining an initial aerodynamic force and an initial blade deformation amount corresponding to the initial aerodynamic force based on the aeroelastic model; determining a corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation amount and the tip loss coefficient database; and assessing the deformation state of the blade based on the initial aerodynamic force and the corrected aerodynamic force.

[0006] In one technical solution of the above-mentioned blade deformation assessment method, the construction of an aeroelastic model that takes into account tip loss includes: based on the blade element momentum theorem, introducing an axial induction factor and a tangential induction factor, and modifying the momentum theorem in combination with the tip loss factor to construct an aerodynamic model; simplifying the blade into a beam unit, and constructing a structural model based on geometrically precise beam theory, material parameters, and structural parameters of the blade; and coupling the aerodynamic model and the structural model to obtain an aeroelastic model that takes into account tip loss.

[0007] In one technical solution of the above-mentioned blade deformation assessment method, the aerodynamic model is constructed by introducing the axial induction factor and the tangential induction factor based on the blade element momentum theorem, and combining the blade tip loss factor to correct the momentum theorem, including: introducing the axial induction factor and the tangential induction factor to describe the velocity reduction of the airflow through the wind rotor; establishing a velocity synthesis relationship, wherein the velocity synthesis relationship includes the relationship between the free stream velocity, the wind rotor speed, the axial induction factor and the tangential induction factor; determining the relationship between the inflow angle, the angle of attack and the pitch angle; and calculating the blade element micro-element lift and blade element micro-element drag based on the airfoil lift coefficient and the airfoil drag coefficient. Based on the blade element micro-element lift and blade element micro-element drag, the normal force and tangential force acting on the blade element are determined; based on the normal force and tangential force acting on the blade element, a calculation formula for the thrust and torque acting on the blade element is determined; based on the momentum theorem, the tip loss factor is applied to the thrust and torque equations of the momentum theorem to obtain a corrected momentum equation; based on the calculation formula for the thrust and torque acting on the blade element and the corrected momentum equation, an axial induction factor and a tangential induction factor are iteratively calculated to determine; based on the calculation formula for the thrust and torque acting on the blade element and the determined axial induction factor and tangential induction factor, an aerodynamic model is obtained.

[0008] In one technical solution of the above-mentioned blade deformation assessment method, the construction of the tip loss coefficient database includes: using a CFD numerical simulation method to determine the aerodynamic data corresponding to multiple preset deformation amplitudes; using a linear interpolation method to calculate the tip loss coefficient under any deformation amplitude based on the aerodynamic data under the multiple preset deformation amplitudes; associating the tip loss coefficient under any deformation amplitude with the corresponding deformation amplitude to construct a tip loss coefficient database.

[0009] In one technical solution of the above-mentioned blade deformation assessment method, the CFD numerical simulation method is used to determine the aerodynamic data corresponding to multiple preset deformation amplitudes, including: generating a corresponding geometric model and dividing the CFD grid based on the multiple preset deformation amplitudes; performing CFD numerical simulation on the multiple preset deformation amplitudes to determine the aerodynamic data corresponding to the multiple preset deformation amplitudes.

[0010] In one technical solution of the above-mentioned blade deformation assessment method, the initial aerodynamic force and the initial blade deformation amount corresponding to the initial aerodynamic force are determined based on the aeroelastic model, including: using the aerodynamic model to calculate the initial aerodynamic force when the blade is not deformed; inputting the initial aerodynamic force into the structural model to determine the initial blade deformation amount corresponding to the initial aerodynamic force.

[0011] In a technical solution of the above-mentioned blade deformation assessment method, the corrected aerodynamic force is determined based on the initial aerodynamic force, the initial blade deformation amount and the tip loss coefficient database, including: based on the initial blade deformation amount and the tip loss coefficient database, using a linear interpolation method to determine the tip loss coefficient corresponding to the initial blade deformation amount; based on the tip loss coefficient corresponding to the initial blade deformation amount and the aerodynamic model, the corrected aerodynamic force is determined.

[0012] In one technical solution of the above-mentioned blade deformation assessment method, the deformation state of the blade is assessed based on the initial aerodynamic force and the corrected aerodynamic force, including: calculating the difference between the corrected aerodynamic force and the initial aerodynamic force, judging whether the difference is within a preset threshold range, and if so, determining the deformation state of the blade based on the blade deformation amount corresponding to the corrected aerodynamic force; otherwise, re-determining the corrected aerodynamic force.

[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 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 blade deformation assessment method is implemented.

[0014] In a third aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored in the computer-readable storage medium, 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 blade deformation assessment method.

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

[0016] The present application provides a method for evaluating blade deformation, which includes: constructing an aeroelastic model that takes into account tip loss, wherein the aeroelastic model includes an aerodynamic model and a structural model; constructing a tip loss coefficient database; determining the initial aerodynamic force and the initial blade deformation corresponding to the initial aerodynamic force based on the aeroelastic model; determining the corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation, and the tip loss coefficient database; and evaluating the deformation state of the blade based on the initial aerodynamic force and the corrected aerodynamic force. Through reasonable modeling and analysis, the present application can accurately identify the deformation state of the blade under different wind speed conditions and achieve high-precision deformation evaluation. It is suitable for the design and operation evaluation of large aspect ratio and long flexible blades, and provides reliable data support for optimizing the design and operation parameters of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The disclosure of this application will become more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Among them:

[0018] Figure 1 This is a flow chart of the main steps of a blade deformation assessment method according to an embodiment of the present application;

[0019] Figure 2 Schematic diagram of the velocity synthesis relationship and aerodynamic force under blade element rotation conditions according to one 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 a blade simplified as a beam model according to an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of a detailed process flow for blade deformation assessment 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. 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 scope of protection of the present application.

[0027] In the description of this application, "module" and "processor" may include hardware, software, or a combination of both. A module may include hardware circuitry, various suitable sensors, communication ports, and memory. It may also include software components, such as program code, or a combination of software and hardware. A processor may be a central processing unit (CPU), a microprocessor, an image processor, a digital signal processor, or any other suitable processor. A processor has data and / or signal processing capabilities. A processor may be implemented in software, hardware, or a combination of both. Computer-readable storage media include 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" refers to all possible combinations of A and B, such as only A, only B, or both A and B. The terms "at least one of A or B" or "at least one of A and B" have similar meanings to "A and / or B" and may include only A, only B, or both A and B. The singular forms "a" and "the" may also include the plural forms.

[0028] With the development trend of larger wind turbines, the aspect ratio of blades has increased significantly, and their structural flexibility has also increased accordingly. The flexibility of blades makes them prone to large bending and torsional deformation under strong wind and turbulent conditions. This dynamic response (including bending, torsion and vibration) not only directly affects the aerodynamic efficiency of the blades, but also reduces their structural stability and service life. In addition, deformation may cause structural fatigue or even failure, leading to serious safety hazards and economic losses. Therefore, how to accurately evaluate the deformation characteristics of flexible blades under different operating conditions has become a key issue in the design and optimization of wind turbines. At present, there are some deformation assessment methods for flexible blades, but these methods are often computationally complex and have limited accuracy, making them difficult to promote and apply in actual engineering.

[0029] To this end, the present application provides a blade deformation assessment method that achieves high-precision deformation assessment through the following steps: constructing an aeroelastic model that takes into account tip loss, including an aerodynamic model and a structural model; constructing a tip loss coefficient database; determining the initial aerodynamic force and its corresponding initial blade deformation based on the aeroelastic model; determining the corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation, and the tip loss coefficient database; and evaluating the deformation state of the blade based on the initial aerodynamic force and the corrected aerodynamic force. Through reasonable modeling and analysis, the present application can accurately identify the deformation state of the blade under different wind speed conditions and achieve high-precision deformation assessment. It is suitable for the design and operation evaluation of large aspect ratio and long flexible blades, and provides reliable data support for optimizing the design and operation parameters of the blade.

[0030] See attached Figure 1 , Figure 1 FIG. 1 is a flow chart showing the main steps of a blade deformation assessment method according to an embodiment of the present application. Figure 1 As shown, the blade deformation assessment method in this embodiment is applicable to deformation assessment of flexible blades, and mainly includes the following steps S101 to S105.

[0031] Step S101: constructing an aeroelastic model that takes into account blade tip losses, wherein the aeroelastic model includes an aerodynamic model and a structural model.

[0032] Step S102: constructing a blade tip loss coefficient database.

[0033] Step S103: Based on the aeroelastic model, determine the initial aerodynamic force and the initial blade deformation corresponding to the initial aerodynamic force.

[0034] Step S104: determining a corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation, and the blade tip loss coefficient database.

[0035] Step S105: Evaluate the deformation state of the blade based on the initial aerodynamic force and the corrected aerodynamic force.

[0036] Based on the method described in steps S101 to S105 above, the present application achieves two-way feedback of aerodynamic load and structural deformation by coupling the aerodynamic model with the structural model, significantly improving the deformation prediction accuracy. By introducing the tip loss factor, the aerodynamic performance degradation caused by tip vortex shedding is accurately corrected, making the aerodynamic load calculation closer to the actual working conditions. In addition, a closed-loop iterative process of aerodynamic force, structural deformation, and corrected aerodynamic force is adopted to dynamically adjust the relationship between aerodynamic load and deformation, which can accurately evaluate the deformation state of the blade.

[0037] The above steps S101 to S105 are further explained below.

[0038] With respect to step S101, in one embodiment, constructing an aeroelastic model that takes into account tip loss includes: based on the blade element momentum theorem, introducing an axial induction factor and a tangential induction factor, and modifying the momentum theorem in combination with the tip loss factor to construct an aerodynamic model; simplifying the blade into a beam unit, and constructing a structural model based on geometrically precise beam theory, material parameters, and structural parameters of the blade; and coupling the aerodynamic model and the structural model to obtain the aeroelastic model that takes into account tip loss.

[0039] Blade Element Momentum Theory (BEM) is the core theory for analyzing the aerodynamic performance of wind turbines. It combines momentum theory and blade element theory and is used to calculate parameters such as load distribution, thrust, and power on wind rotor blades.

[0040] Geometrically Exact Beam Theory (GEBT) is a theoretical framework for describing the mechanical behavior of slender structures (such as beams and wings) under geometrically nonlinear conditions, such as large deformations and rotations. Its core feature is its ability to capture nonlinear deformations through precise mathematical descriptions, avoiding the simplifying assumptions of traditional linear beam theory.

[0041] Specifically, when constructing an aerodynamic model based on the blade element momentum theorem (BEM), it is necessary to quantify the velocity reduction effect of the airflow when passing through the wind wheel through the axial induction factor and the tangential induction factor, and modify the momentum theorem in combination with the blade tip loss factor, ultimately achieving high-precision calculation of the aerodynamic force.

[0042] Based on the geometrically accurate beam theory (GEBT), the blade is simplified into a beam element, and the material and structural parameters of the blade are defined. The nonlinear motion control equations of the blade are constructed through finite element discretization to obtain the structural model.

[0043] In one embodiment, the aerodynamic model is constructed by introducing the axial induction factor and the tangential induction factor based on the blade element momentum theorem, and combining the blade tip loss factor to modify the momentum theorem, including: introducing the axial induction factor and the tangential induction factor to describe the speed reduction of the airflow through the wind wheel; establishing a speed synthesis relationship, wherein the speed synthesis relationship includes the relationship between the free flow velocity, the wind wheel speed, the axial induction factor and the tangential induction factor; determining the relationship between the inflow angle, the angle of attack and the pitch angle; calculating the blade element micro-element lift and blade element micro-element drag based on the airfoil lift coefficient and the airfoil drag coefficient; and calculating the blade element micro-element lift and blade element micro-element drag based on the blade element micro-element. The invention relates to a method for determining the normal force and tangential force acting on the blade element by calculating the lift of the blade element and the infinitesimal drag of the blade element; determining the calculation formula of the thrust and torque acting on the blade element based on the normal force and tangential force acting on the blade element; applying the tip loss factor to the thrust and torque equations of the momentum theorem based on the momentum theorem to obtain a corrected momentum equation; iteratively calculating and determining the axial induction factor and the tangential induction factor based on the calculation formula of the thrust and torque acting on the blade element and the corrected momentum equation; and obtaining an aerodynamic model based on the calculation formula of the thrust and torque acting on the blade element and the determined axial induction factor and tangential induction factor.

[0044] Specifically, the construction of the aerodynamic model is based on the following assumptions: the wind wheel is simplified into a flat propeller disk, which is assumed to be composed of an infinite number of blades; the incoming flow is a uniform steady flow, and the influence of air compressibility is ignored; the radial blade elements are assumed to be independent of each other, there is no interaction force between the blade elements, and the radial flow of flow field particles is ignored; the influence of wake induced velocity is ignored.

[0045] When the airflow passes through the rotating plane of the blades and the wind wheel, its axial velocity and tangential velocity will change. Therefore, the axial induction factor a and the tangential induction factor b are introduced to reflect the velocity reduction of the airflow when passing through the wind wheel.

[0046] See attached Figure 2 , Figure 2 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 speed synthesis relationship is expressed as:

[0047] Where V is the free stream velocity; φ is the inflow angle; Ω is the rotor speed; a is the axial induction factor; b is the tangential induction factor; and r is the radius of the blade element at the blade position.

[0048] The relationship between the inflow angle, angle of attack, and pitch angle is expressed as: α=φ-β

[0049] Where α is the angle of attack; β is the pitch angle.

[0050] Based on the blade chord length, air density, airfoil lift coefficient, airfoil drag coefficient, and incoming flow velocity, the blade element lift and blade element drag are calculated. The calculation formula for the blade element lift is:

[0051] The calculation formula of blade element resistance is:

[0052] Where ρ is the air density, W is the combined velocity of the incoming flow, C is the chord length, and C L is the airfoil lift coefficient, C D is the airfoil drag coefficient, and r is the radius of the blade element at the blade position.

[0053] Decompose the lift and drag acting on the blade element into the direction of the rotor rotation plane and the direction perpendicular to the rotor rotation plane to obtain the normal force F acting on the blade element n and tangential force F t .

[0054] Normal force F n The calculation formula is:

[0055] Tangential force F t The calculation formula is:

[0056] Where C n is the normal force coefficient, C t is the tangential force coefficient, expressed as: C n =C L cosφ+CD sinφ C t =C L sinφ-C D cosφ

[0057] Based on the normal force and tangential force acting on the blade element, the calculation formula for the thrust and torque of the blade element at a distance r from the center of the wind rotor is determined as follows:

[0058] Where, dT 叶素 is the thrust on the blade element, dM 叶素 is the torque on the blade element, and B is the number of blades.

[0059] According to the momentum theorem, the thrust and torque acting on the infinitesimal ring with a width of dr at the radius r of the wind wheel are: dT 动量 =4πρV 2 (1-a)ardr dM 动量 =4πρVΩ(1-a)br 3 dr

[0060] However, in actual situations, due to the limited number of wind turbine blades, the propeller disc will produce tip vortex shedding, and part of the air will flow from the lower surface of the blade to the upper surface, resulting in secondary flow of the inflow near the tip. The existence of this tip vortex significantly reduces the aerodynamic performance near the tip of the blade. At this time, the blade element momentum theory cannot accurately calculate the aerodynamic force near the tip of the blade. The energy loss caused by tip vortex shedding will reduce the output power of the wind rotor. In order to compensate for the calculation error caused by tip vortex shedding, the Prandtl tip loss factor is introduced. The error caused by tip loss can be expressed by the tip loss factor F:

[0061] Then, the tip loss factor F is applied to the thrust and torque equations of the momentum theorem to obtain the revised momentum equation: dT 动量 =4πρV 2 (1-a)arFdr dM 动量 =4πρVΩ(1-a)br 3 Fdr

[0062] Based on the calculation formula of thrust and torque on the blade element and the modified momentum equation, the axial induction factor and tangential induction factor are determined by iterative calculation. Specifically, dT 叶素 =dT 动量 , dM 叶素 =dM 动量, so the axial induction factor and tangential induction factor can be obtained as:

[0063] During the calculation, first initialize the axial induction factor a and the tangential induction factor b, assuming a = b = 0; then calculate the inflow angle φ based on the velocity synthesis relationship. After obtaining the inflow angle, the angle of attack corresponding to the airfoil can be obtained. Referring to the airfoil data table, the lift and drag coefficients at the corresponding angle of attack can be obtained, thereby obtaining the corresponding normal force coefficient and tangential force coefficient. Substituting the normal force coefficient, tangential force coefficient, and inflow angle into the above a and b solution formulas can obtain the axial induction factor a and the tangential induction factor b, thus completing an iterative process. Repeat this process until a and b converge. Then substitute the converged a and b values ​​back into the calculation formulas for the thrust and torque acting on the blade element to obtain the aerodynamic force on the blade element. Integrating the aerodynamic force acting on the blade element along the blade span direction can obtain the aerodynamic loads on the blade and the wind rotor.

[0064] In one embodiment, the blade is simplified into beam elements, and a structural model is constructed based on geometrically accurate beam theory, material parameters, and structural parameters of the blade.

[0065] Specifically, the blade is simplified into a beam element, and the deformation state of the beam is as follows: Figure 3 shown.

[0066] The equation of motion for a geometrically accurate beam is based on the law of conservation of momentum and is expressed as:

[0067] The first formula is the linear momentum conservation equation of the beam, and the second formula is the relationship between the change in angular momentum of the beam and the internal and external moments.

[0068] Where h is the linear momentum in the inertial coordinate system, g is the angular momentum in the inertial coordinate system; 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 reference line of the beam; f and m are the distributed force and moment applied to the beam structure. The symbol F' represents the derivative of the relative axial displacement. Indicates the derivative with respect to time. Tilde operator Defines a skew-symmetric tensor corresponding to a given vector. The superscript “(·)” denotes the time derivative. T is the transpose operator.

[0069] Establish constitutive relationships between velocity and momentum, one-dimensional strain measurements, and cross-sectional results. The constitutive equations relate kinematic variables to mechanical responses:

[0070] Where M is the 6×6 section mass matrix, C is the 6×6 section stiffness matrix; ε and k are the one-dimensional strain and curvature, respectively; ω is the angular velocity vector defined by the rotation tensor R, where ω = axial(RR T ), the vector a is associated with a second-order tensor A, whose components are defined as:

[0071] The one-dimensional strain ε and curvature k can be expressed as:

[0072] Where K = axial[(RR0)'(RR0) T ], K is the section curvature vector decomposed on the basis of inertia, 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. The above equations together form the mathematical description of the elasticity problem of a geometrically accurate beam.

[0073] The nonlinear governing motion equations of the beam are solved iteratively using the Newton-Raphson method, and the beam elements are discretized using the Legendre spectral finite element method. The linearized form of the nonlinear governing motion equations is shown below:

[0074] Where, is the unit mass matrix; is the rotation matrix; is the stiffness matrix; To express the generalized element acceleration; is the generalized speed, is the generalized node displacement array increment; Represents externally applied load; Expressed as unit force.

[0075] The time integral is calculated using the generalized alpha time integrator: |ΔU (i)T ( t+Δt R- t+Δt F (i-1) )|≤|ε E [ΔU (1)T ( t+Δt R- t F)]|

[0076] Where ΔU is the increment of the displacement vector; R is the externally applied nodal load vector; F is the nodal force vector corresponding to the internal unit stress; εE is the preset energy tolerance; the superscript on the left side of the variable indicates the time value, indicating that it is in dynamic analysis, and the superscript on the right side indicates the number of iterations.

[0077] The three-dimensional rotation of the beam section during deformation is described by the Wiener-Milenkovic parameter, which is in the form of:

[0078] in, is the rotation angle, and n is the unit vector of the rotation axis.

[0079] The deformation percentage is used to quantify the degree of blade deformation and is expressed as:

[0080] Where ω is the tip deformation and l is the total length of the blade.

[0081] The blade is simplified into a beam model as Figure 4 As shown in the figure, by simplifying the complex blade geometry into a beam model, combining the above theory and inputting the corresponding structural parameters, the node degrees of freedom are numerically realized by Legendre spectrum finite element, and the trapezoidal quadrature method is used to model the wind turbine blade with a single unit. The Wiener-Milenkovic parameter is used to represent the three-dimensional rotation, and the linear displacement and angular displacement of each node of the blade are obtained. Secondly, the nonlinear motion control equation is solved by Newton-Raphson. After linearization, the generalized α time integrator is used to determine whether the equation has converged.

[0082] With respect to step S102, in one embodiment, constructing a tip loss coefficient database includes: using a CFD numerical simulation method to determine aerodynamic data corresponding to a plurality of preset deformation amplitudes; using a linear interpolation method to calculate the tip loss coefficient under an arbitrary deformation amplitude based on the aerodynamic data under the plurality of preset deformation amplitudes; associating the tip loss coefficient under the arbitrary deformation amplitude with the corresponding deformation amplitude to construct a tip loss coefficient database.

[0083] Specifically, CFD numerical simulation is used to obtain the aerodynamic data of the blade under multiple preset deformation amplitudes, and CFD numerical simulation is performed to calculate the aerodynamic forces corresponding to the multiple preset deformation amplitudes.

[0084] The deformation amplitude of the blade may not be equal to the data used in the simulation, which requires a continuous tip loss coefficient to describe the aerodynamic characteristics under arbitrary deformation amplitude. To this end, a linear interpolation formula is used to calculate the tip loss coefficient F under arbitrary deformation amplitude based on the data obtained from CFD simulation. extraThe interpolation method can generate smooth curves between data points, ensuring the continuity and accuracy of the loss coefficient over the entire deformation range, thereby better simulating the aerodynamic performance of the actual blade under different deformations.

[0085] Assume that two adjacent deformation amplitude points ω are known i and ω i+1 The corresponding tip loss coefficient F extra(i) and F extra(i+1) , then for any deformation amplitude ω in the interval (ω i ,ω i+1 ), the interpolation formula is:

[0086] Where ω is the tip deformation deflection in the interval (ω i ,ω i+1 ) within any deformation range.

[0087] The obtained blade tip loss coefficient under any deformation amplitude is associated with the corresponding deformation amplitude to construct a blade tip loss coefficient database.

[0088] In one embodiment, the CFD numerical simulation method is used to determine the aerodynamic data corresponding to multiple preset deformation amplitudes, including: generating a corresponding geometric model and dividing the CFD grid based on the multiple preset deformation amplitudes; performing CFD numerical simulation on the multiple preset deformation amplitudes to determine the aerodynamic data corresponding to the multiple preset deformation amplitudes.

[0089] Specifically, multiple preset deformation amplitudes can be set as η1 = 0%, η2 = 5%, η3 = 10%, η4 = 15%, and η5 = 20%. A blade geometry model is generated for each of the preset deformation amplitudes, and a CFD calculation grid is drawn. A CFD numerical simulation is performed on the grid model to calculate the blade aerodynamic force corresponding to each preset deformation amplitude. The aerodynamic force after the blade deformation is compared with the aerodynamic force of the undeformed blade to obtain the additional tip loss coefficient, which is defined as F extra , and is associated with a preset deformation amplitude.

[0090] Regarding step S103, in one embodiment, determining the initial aerodynamic force and the initial blade deformation corresponding to the initial aerodynamic force based on the aeroelastic model includes: using the aerodynamic model to calculate the initial aerodynamic force when the blade is not deformed; inputting the initial aerodynamic force into the structural model to determine the initial blade deformation corresponding to the initial aerodynamic force.

[0091] Specifically, the initial aerodynamic force F1 of the blade when it is not deformed is calculated through the aerodynamic model, and the initial aerodynamic force F1 is input into the structural model to obtain the initial deformation deflection w1 of the blade under the initial aerodynamic force F1 as the initial blade deformation corresponding to the initial aerodynamic force.

[0092] For step S104, in one embodiment, determining the corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation and the tip loss coefficient database includes: determining the tip loss coefficient corresponding to the initial blade deformation using a linear interpolation method based on the initial blade deformation and the tip loss coefficient database; and determining the corrected aerodynamic force based on the tip loss coefficient corresponding to the initial blade deformation and the aerodynamic model.

[0093] Specifically, after the blade is deformed, the initial aerodynamic force F1 acting on the blade will change, and the aerodynamic force needs to be re-evaluated.

[0094] According to the initial blade deformation, combined with the additional blade tip loss database, the interpolation method is used to obtain the blade tip loss coefficient F corresponding to the initial blade deformation. extra , and based on the tip loss coefficient F corresponding to the initial blade deformation extra , and obtain the corrected aerodynamic force F2.

[0095] Specifically:

[0096] Tip loss coefficient F corresponding to the initial blade deformation extra , calculate the new values ​​of the axial induction factor a and the tangential induction factor b:

[0097] Where F(r)=F extra *F, F(r) is the tip loss coefficient F extra The product of the tip loss factor F.

[0098] Compare the new values ​​of a and b with the values ​​of the previous iteration. If the new values ​​of a and b are within the error range compared with the values ​​of the previous iteration, the new values ​​can be taken; if not, the new values ​​of a and b are used as the values ​​of the previous iteration, and the new values ​​of the axial induction factor a and the tangential induction factor b are recalculated, and the iteration continues.

[0099] Based on the determined axial induction factor a and tangential induction factor b, the aerodynamic force on the blade element can be obtained by substituting it back into the thrust and torque formula of the infinitesimal ring. The aerodynamic load on the blade and the wind wheel can be obtained by integrating the aerodynamic force on the blade element along the span direction of the blade, and the corrected aerodynamic force F2 can be obtained.

[0100] For step S105, in one embodiment, the deformation state of the blade is evaluated based on the initial aerodynamic force and the corrected aerodynamic force, including: calculating the difference between the corrected aerodynamic force and the initial aerodynamic force, and judging whether the difference is within a preset threshold range; if so, determining the deformation state of the blade based on the blade deformation amount corresponding to the corrected aerodynamic force; otherwise, re-determining the corrected aerodynamic force.

[0101] Specifically, the corrected aerodynamic force F2 is compared with the initial aerodynamic force F1. If the difference between the initial aerodynamic force and the corrected aerodynamic force is outside the preset threshold range, the iteration is repeated to continue updating the blade aerodynamic force. Through this iteration, the deformation state of the wind turbine blade under actual operating conditions is obtained.

[0102] If the difference between the initial aerodynamic force and the corrected aerodynamic force is within a preset threshold range, the blade deformation corresponding to the corrected aerodynamic force (the blade deformation in the current iteration step) is taken as the final deformation state of the blade.

[0103] See attached Figure 5 , Figure 5 FIG. 1 is a schematic diagram of a detailed process flow for blade deformation assessment according to an embodiment of the present application. Figure 5 As shown, in this embodiment, the blade deformation assessment method includes the following steps:

[0104] Step S201, constructing an aeroelastic model taking into account blade tip loss, the aeroelastic model including an aerodynamic model and a structural model;

[0105] Step S202, constructing a blade tip loss coefficient database;

[0106] Step S203, obtaining wind load, determining initial aerodynamic force based on the aerodynamic model, and determining initial blade deformation based on the structural model;

[0107] Step S204, determining a corrected aerodynamic force based on the initial blade deformation and in combination with a blade tip loss coefficient database;

[0108] Step S205, calculate the difference between the corrected aerodynamic force and the initial aerodynamic force, and determine whether it is within a preset threshold range. If so, convergence is determined to obtain the final deformation state of the blade; otherwise, reiterate and continue to update the blade aerodynamic force.

[0109] This application establishes an aeroelastic model of wind turbine blades based on the blade element momentum theory (BEM) and geometrically accurate beam theory (GEBT) and introduces an additional tip loss coefficient. Through reasonable modeling and analysis techniques, the aeroelastic model is used to evaluate the deformation state of flexible blades under different wind speed conditions and optimize the design and operating parameters of the blades.

[0110] 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 will understand that in order to achieve the effect of the present application, different steps do not have to be performed in such an order. They can be performed 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 scope of protection of this application.

[0111] It will be understood by those skilled in the art that all or part of the processes in the method for implementing the above 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. When the computer program is executed by a processor, it can implement the steps of the above-mentioned various method embodiments. The computer program includes computer program code, which 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, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0112] Another aspect of the present application provides an electronic device.

[0113] See attached Figure 6 , Figure 6 exemplarily shows that the memory 11 and processor 12 are communicatively connected 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 communicatively connected to the at least one processor; wherein the memory stores a computer program that, when executed by the at least one processor, implements the blade deformation assessment method described in any of the above embodiments.

[0114] Another aspect of the present application provides a computer-readable storage medium.

[0115] In one embodiment of a computer-readable storage medium according to the present application, the computer-readable storage medium can be configured to store a program for executing the blade deformation assessment method of the above-described method embodiment. This program can be loaded and executed by a processor to implement the above-described blade deformation assessment method. For ease of illustration, only the portions relevant to the embodiments of the present application are shown. For specific technical details not disclosed, please refer to the method section of the embodiments of the present application. The computer-readable storage medium can be a storage device formed by various electronic devices. Optionally, in the embodiments of the present application, the computer-readable storage medium is a non-transitory computer-readable storage medium.

[0116] Thus far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection 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 may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A blade deformation assessment method, characterized in that: The method comprises: Constructing an aeroelastic model that takes into account blade tip loss, wherein the aeroelastic model includes an aerodynamic model and a structural model; Construct a database of blade tip loss coefficients; determining an initial aerodynamic force and an initial blade deformation corresponding to the initial aerodynamic force based on the aeroelastic model; determining a corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation, and the tip loss coefficient database; The deformation state of the blade is evaluated based on the initial aerodynamic force and the corrected aerodynamic force.

2. The blade deformation assessment method according to claim 1, characterized in that: The aeroelastic model considering blade tip loss is constructed, including: Based on the blade element momentum theorem, the axial induction factor and the tangential induction factor are introduced, and the momentum theorem is modified by combining the blade tip loss factor to construct an aerodynamic model. The blade is simplified into beam elements, and a structural model is constructed based on geometrically accurate beam theory, material parameters and structural parameters of the blade; By coupling the aerodynamic model and the structural model, an aeroelastic model that takes tip losses into account is obtained.

3. The blade deformation assessment method according to claim 2, characterized in that: Based on the blade element momentum theorem, the axial induction factor and the tangential induction factor are introduced, and the momentum theorem is modified in combination with the blade tip loss factor to construct an aerodynamic model, including: Axial induction factor and tangential induction factor are introduced to describe the velocity reduction of airflow passing through the wind wheel; Establishing a velocity synthesis relationship, wherein the velocity synthesis relationship includes a relationship between the free stream velocity, the rotor speed, the axial induction factor, and the tangential induction factor; Determine the relationship between inflow angle, angle of attack, and pitch angle; Calculate the lift and drag of blade elements based on the lift coefficient and drag coefficient of the airfoil; Based on the blade element lift and blade element drag, determine the normal force and tangential force acting on the blade element; Based on the normal force and tangential force acting on the blade element, a calculation formula for the thrust and torque exerted on the blade element is determined; Based on the momentum theorem, the tip loss factor is applied to the thrust and torque equations of the momentum theorem to obtain the revised momentum equation; Based on the calculation formula of the thrust and torque exerted on the blade element and the modified momentum equation, iteratively calculate and determine the axial induction factor and the tangential induction factor; An aerodynamic model is obtained based on the calculation formulas of the thrust and torque acting on the blade element and the determined axial induction factor and tangential induction factor.

4. The blade deformation assessment method according to claim 1, characterized in that: The step of constructing a blade tip loss coefficient database includes: Use CFD numerical simulation method to determine the aerodynamic data corresponding to multiple preset deformation amplitudes; Using a linear interpolation method, based on the aerodynamic force data under the plurality of preset deformation amplitudes, the blade tip loss coefficient under any deformation amplitude is calculated; The blade tip loss coefficient under the arbitrary deformation amplitude is associated with the corresponding deformation amplitude to construct a blade tip loss coefficient database.

5. The blade deformation assessment method according to claim 4, characterized in that: The CFD numerical simulation method is used to determine aerodynamic data corresponding to a plurality of preset deformation amplitudes, including: Generate corresponding geometric models and divide CFD meshes based on multiple preset deformation amplitudes; Perform CFD numerical simulation on the multiple preset deformation amplitudes to determine aerodynamic data corresponding to the multiple preset deformation amplitudes.

6. The blade deformation assessment method according to claim 1, characterized in that: The determining of the initial aerodynamic force and the initial blade deformation corresponding to the initial aerodynamic force based on the aeroelastic model includes: The aerodynamic model is used to calculate the initial aerodynamic force when the blade is not deformed; The initial aerodynamic force is input into the structural model to determine an initial blade deformation corresponding to the initial aerodynamic force.

7. The blade deformation assessment method according to claim 1, characterized in that: The determining of the corrected aerodynamic force based on the initial aerodynamic force, the initial blade deformation, and the blade tip loss coefficient database includes: Based on the initial blade deformation and the blade tip loss coefficient database, a linear interpolation method is used to determine the blade tip loss coefficient corresponding to the initial blade deformation; A corrected aerodynamic force is determined based on a tip loss coefficient corresponding to the initial blade deformation and the aerodynamic model.

8. The blade deformation assessment method according to claim 1, characterized in that: The step of evaluating the deformation state of the blade based on the initial aerodynamic force and the corrected aerodynamic force includes: Calculating a difference between the corrected aerodynamic force and the initial aerodynamic force, determining whether the difference is within a preset threshold range, and if so, determining a deformation state of the blade based on an amount of blade deformation corresponding to the corrected aerodynamic force; Otherwise, redetermine the corrected aerodynamic forces.

9. An electronic device comprising at least one processor and at least one memory, wherein the memory is adapted to store a plurality of program codes, wherein: The program code is suitable for being loaded and run by the processor to execute the blade deformation assessment method according to any one of claims 1 to 8.

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 blade deformation assessment method according to any one of claims 1 to 8.

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