Flutter value determination method, system and equipment of wind driven generator blade and medium

Abstract

The invention relates to the technical field of wind driven generators, particularly provides a flutter value determination method, system and equipment for wind driven generator blades and a medium, and aims to solve the problem that the influence of fluid flow on blade structure movement is not considered when a kinetic model is used for calculating a flutter value. The method comprises the following steps: establishing a structure motion equation of flutter response according to the structure of the wind driven generator blade, performing numerical simulation on a two-dimensional flow field to establish a flow control equation, establishing a coupling system equation according to the structure motion equation and the flow control equation, and solving the coupling system equation to obtain a flutter value. On one hand, a structure motion equation is used for describing dynamics and stress conditions of a wind driven generator blade structure, on the other hand, a flow control equation is used for describing flow field data around the wind driven generator blade, and then a coupling system equation is solved to obtain a flutter value. The problem that the influence of fluid flow on blade structure movement is not considered when a kinetic model is used for calculating a flutter value is solved.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbines, and in particular to a method, system, device and medium for determining flutter values ​​of wind turbine blades. Background Art

[0002] With the development trend of large-scale wind turbines, the aspect ratio of blades has increased dramatically, and the problem of stall flutter has become increasingly prominent. Among them, stall flutter is an unstable vibration phenomenon caused by the impact of airflow on the blades when they rotate at high speed. Stall flutter may damage the blade structure, reduce efficiency or cause equipment failure. Therefore, calculating the flutter value of the blade is of great significance to optimizing the blade design. In the prior art, dynamic models are usually used to calculate the flutter value, without considering the impact of fluid flow on the movement of the blade structure.

[0003] Accordingly, the art needs a new solution for determining the flutter value of wind turbine blades to solve the above-mentioned problem. Summary of the invention

[0004] In order to overcome the above-mentioned defects, the present application is proposed to solve or at least partially solve the technical problem that the influence of fluid flow on the movement of blade structure is not considered when calculating flutter values ​​using a dynamic model.

[0005] In a first aspect, a method for determining the flutter value of a wind turbine blade is provided, the method comprising: establishing a structural motion equation of the flutter response according to the structure of the wind turbine blade; numerically simulating a two-dimensional flow field to establish a flow control equation; establishing a coupling system equation according to the structural motion equation and the flow control equation; and solving the coupling system equation to obtain the flutter value.

[0006] In a technical solution of the above-mentioned method for determining the flutter value of a wind turbine blade, the flutter response includes the angular displacement, angular velocity, and angular acceleration of the structural flutter of the wind turbine blade, and the structural motion equation of the flutter response is established according to the structure of the wind turbine blade, including: simplifying the wind turbine blade into a two-dimensional airfoil with one rotational degree of freedom; and establishing the structural motion equation regarding the angular displacement, angular velocity, and angular acceleration based on the structural parameters of the two-dimensional airfoil.

[0007] In one technical solution of the above-mentioned method for determining the flutter value of a wind turbine blade, the structural motion equations about the angular displacement, angular velocity, and angular acceleration established based on the structural parameters of the two-dimensional airfoil are expressed as follows: k s =2πf s c / U ∞

[0008] μ=4m / (πρc 2 )

[0009] Wherein, θ represents the angular displacement, represents the angular velocity, represents the angular acceleration, f s represents the structural natural frequency, c represents the chord length of the airfoil, U ∞ represents the incoming wind speed, ζ represents the structural damping coefficient; C M represents the pitching moment coefficient of the airfoil; m represents the mass of the airfoil, ρ represents the fluid density; r represents the radius of gyration of the airfoil.

[0010] In one technical solution of the above-mentioned method for numerically determining the flutter of a wind turbine blade, the numerical simulation of the two-dimensional flow field to establish the flow control equation includes: numerically simulating the two-dimensional flow field using an unsteady Reynolds time-averaged method based on a turbulence model to establish the following flow control equation:

[0011]

[0012] Among them, U i , U j They represent the fluid at point x at time t. i ,y i The velocity component at represents the average velocity of the fluid in the x direction, ρ represents density, p represents pressure, v represents viscosity, S ji The fluid at point x at time t i ,y i The strain velocity tensor at , represents the Reynolds stress term.

[0013] In one technical solution of the above-mentioned method for determining the flutter value of a wind turbine blade, the coupling system equation established according to the structural motion equation and the flow control equation is expressed as follows:

[0014]

[0015] Among them, θ n , Respectively represent the angular displacement, angular velocity, and angular acceleration at time t, θ n+1 represents the angular displacement at time t+1, C Mn+1 Represents the pitching moment coefficient at time t+1.

[0016] In a technical solution of the above-mentioned method for determining the flutter value of the wind turbine blade, the flutter value is obtained by solving the coupled system equation, including: solving the flow control equation to obtain the pitch moment coefficient at time t; and iteratively solving the angular displacement at time t+1 based on the pitch moment coefficient at time t and the coupled system equation.

[0017] In a technical solution of the above-mentioned method for determining the flutter value of a wind turbine blade, the method further includes: performing structural optimization or fault analysis on the wind turbine blade according to the flutter value.

[0018] In a second aspect, a system for determining the flutter value of a wind turbine blade is provided, the system comprising: a first simulation module, for establishing a structural motion equation of a flutter response according to the structure of the wind turbine blade; a second simulation module, for numerically simulating a two-dimensional flow field to establish a flow control equation; a third simulation module, for establishing a coupling system equation according to the structural motion equation and the flow control equation; and a solver module, for solving the coupling system equation to obtain a flutter value.

[0019] In a third aspect, a smart 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 in the above-mentioned first aspect or any corresponding technical solution is implemented.

[0020] In a fourth aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, wherein the program codes are suitable for being loaded and run by a processor to execute the method in the above-mentioned first aspect or any corresponding technical solution thereof.

[0021] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0022] In the technical solution of the present application, on the one hand, the structural motion equation is used to describe the dynamics and stress conditions of the wind turbine blade structure, and on the other hand, the flow control equation is used to describe the flow field data such as pressure, velocity, and stress distribution of the fluid around the wind turbine blade. The above structural motion equation and flow control equation are combined to obtain the coupled system equation, thereby achieving the purpose of describing the interaction between structural motion and fluid flow, simulating the aerodynamic characteristics and structural response of the blade in a complex wind field, and finally solving the coupled system equation to obtain the flutter value. The effect of improving the accuracy and reliability of flutter numerical calculation is achieved, and the problem that the use of dynamic models to calculate flutter values ​​does not consider the influence of fluid flow on the blade structure movement is solved. The flutter value can further achieve the purpose of providing accurate data support for wind turbine blade design and fault analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosure of the present application will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0024] Figure 1 It is a schematic flow chart of the main steps of a method for determining a flutter value of a wind turbine blade according to an embodiment of the present application;

[0025] Figure 2a is a schematic diagram of a simplified model of a wind turbine blade according to an embodiment of the present application;

[0026] Figure 2b is a schematic diagram of a kinematic model of an airfoil structure according to an embodiment of the present application;

[0027] Figure 3 is a schematic diagram of the overall framework of fluid-solid coupling numerical simulation according to an embodiment of the present application;

[0028] Figure 4 It is a schematic diagram of the main structure block diagram of a system for determining the flutter value of a wind turbine blade according to an embodiment of the present application;

[0029] Figure 5 The figure is a schematic diagram of the connection relationship between the processor and the memory of a smart device according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0031] In the description of the present application, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. The terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, it can be indirectly connected through an intermediate medium, it can also be the internal communication of two elements, it can be a wireless connection, or it can be a wired connection.

[0032] In addition, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, and memories, and may also include software parts, such as program codes, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware, or a combination of the two. Computer-readable storage media include any suitable media that can store program codes, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc.

[0033] In addition, if the meaning of "and / or" appears in this application, it includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "one" and "this" can also include plural forms.

[0034] With the development trend of large-scale wind turbines, the aspect ratio of blades has increased dramatically, the structural flexibility has increased, and the stall flutter problem has become increasingly prominent. During the blade design and operation process, when the blade is in a large angle of attack operating condition, flow separation will occur at its trailing edge, and the aerodynamic performance of the blade will be significantly affected. Because the blades are slender and flexible, the coupling of unsteady flow and elastic blades can easily cause stall flutter, which seriously affects the fatigue life of the structure. Under some conditions, it may even cause structural damage, causing huge safety hazards and economic losses. Existing calculation methods are difficult to accurately predict the dynamic response characteristics of the above blades at different wind speeds and angles of attack.

[0035] In order to solve the above problems, the present application provides a method for determining the flutter value of a wind turbine blade. Figure 1 , Figure 1 FIG. 1 is a flow chart of the main steps of a method for determining the flutter value of a wind turbine blade according to an embodiment of the present application. Figure 1 As shown, the method for determining the flutter value of a wind turbine blade in the embodiment of the present application mainly includes the following steps S101 to S104:

[0036] Step S101, establishing a structural motion equation of a flutter response according to the structure of a wind turbine blade.

[0037] In this embodiment, by analyzing the structure and mechanical properties of the wind turbine blade itself, a mathematical expression or model describing the blade flutter response is derived. The flutter response includes the angular displacement, angular velocity, and angular acceleration of the wind turbine blade structure flutter; the structure and mechanical properties of the blade itself include the structural kinematic model, structural natural frequency, mass, density, etc.

[0038] In one embodiment, establishing the structural motion equation of the flutter response may include the following steps: clarifying the boundary conditions of the model (such as fixed constraints, degrees of freedom), setting the physical properties of the blade structure (such as mass density, stiffness distribution), and introducing necessary assumptions (such as ignoring certain nonlinear effects); based on the linear vibration theory and the actual situation of the blade structure, establishing a differential equation or integral equation describing the dynamic behavior of the blade, namely the structural motion equation, which is used to reflect the motion state of the blade under force and the relationship between force and displacement.

[0039] Step S102, numerically simulate the two-dimensional flow field to establish the flow control equation.

[0040] In this embodiment, the flow control equation is a basic mathematical equation that describes the motion of a fluid, and can describe the spatial distribution and temporal variation of physical quantities such as the velocity and pressure of the fluid. The flow control equation (such as the Reynolds equation, the Newton-Rogers equation, and the Darcy-Wiegand equation) is obtained by modeling the physical phenomena in the two-dimensional flow field using numerical methods, and these equations reflect the motion laws of the fluid at different time and space scales.

[0041] In one embodiment, the process of establishing the flow control equation may include the following steps: deriving the corresponding mathematical model according to the flow characteristics to be studied. For example, to study the flow characteristics of a fluid under certain conditions, the corresponding mathematical model can be derived based on physical laws such as conservation of energy and conservation of momentum. Then, a suitable numerical method (such as finite difference method, finite volume method, finite element method) is selected as the numerical model. The flow field is divided into many small grid units to obtain a discretized grid, and finally the selected numerical method and grid are used to establish a research model.

[0042] Step S103, establishing a coupled system equation based on the structural motion equation and the flow control equation.

[0043] In this embodiment, the structural motion equation established in step S101 is combined with the flow control equation established in step S102 to obtain a coupled system equation that describes the interaction between structural motion and fluid flow, thereby achieving the purpose of simulating the aerodynamic characteristics and structural response of the blade in a complex wind field.

[0044] In one implementation, establishing the coupled system equations may be to use flow field data such as velocity and pressure in the fluid dynamics control equations as inputs in the structural motion equations.

[0045] Step S104, solving the coupled system equation to obtain a flutter value.

[0046] In this embodiment, the coupled system equation obtained in step S103 is solved to obtain the flutter (response) value. Specifically, the coupled system equation can be discretized by numerical methods such as time stepping method and finite element method using CFD (Computational Fluid Dynamics) and CSD (Computational Structure Dynamics) solvers, and iteratively solved. Since the coupled system equation takes into account the interaction and influence between fluid and solid, the flutter value of the wind turbine blade calculated by the above method is more accurate and reliable.

[0047] Based on the method described in the above steps S101 to S104, on the one hand, the structural motion equation is used to describe the dynamics and stress conditions of the wind turbine blade structure, and on the other hand, the flow control equation is used to describe the flow field data such as pressure, velocity, and stress distribution of the fluid around the wind turbine blade. The coupled system equation is obtained by combining the structural motion equation and the flow control equation, and the coupled system equation is solved to obtain the flutter value. The purpose of improving the accuracy and reliability of the flutter numerical calculation is achieved, and the problem that the use of the dynamic model to calculate the flutter value does not consider the influence of the fluid flow on the blade structure movement is solved.

[0048] In one implementation of the embodiment of the present application, the flutter response includes the angular displacement, angular velocity, and angular acceleration of the flutter of the wind turbine blade structure, and the above step S101 may further include the following steps S1011 and S1012:

[0049] Step S1011, simplifying the wind turbine blade into a two-dimensional airfoil with one rotational degree of freedom.

[0050] In this embodiment, if Figure 2a As shown, the vertical section of the wind turbine blade is a two-dimensional airfoil, and the following assumptions are made for the wind turbine blade:

[0051] (1) Simplify the wind turbine blade into a two-dimensional airfoil.

[0052] (2) The simplified two-dimensional airfoil has only one rotational degree of freedom, that is, it can rotate freely around the rotation center under the incoming wind, and its structural motion system is a mass-spring-damper system.

[0053] Step S1012, establishing a structural motion equation regarding angular displacement, angular velocity, and angular acceleration based on the structural parameters of the two-dimensional airfoil.

[0054] In this embodiment, if Figure 2b As shown, the (airfoil) structure performs a single-degree-of-freedom pitch motion around the center of rotation. Among them, c represents the chord line of the airfoil, θ0 represents the torsion angle of the blade installation, that is, the blade torsion angle, α represents the (incoming flow) angle of attack, θ represents the angular displacement of the structural flutter, and G represents the horizontal line. It should be noted that the blades are usually not installed horizontally, and there is a fixed inclination angle, that is, the torsion angle θ0. When the wind blows the blades to vibrate, there is a small oscillation based on θ0, which is the angular displacement of the flutter θ. Furthermore, the angle of attack α, the blade torsion angle α, and the flutter angle θ satisfy the following formula:

[0055] α=θ0+θ

[0056] In one implementation, the relationship between the blade twist angle and the flutter angle is analyzed, and the following structural motion equations regarding angular displacement, angular velocity, and angular acceleration are established based on the laws of physics and the structural parameters of the two-dimensional airfoil:

[0057]

[0058] Where θ represents the angular displacement, represents the angular velocity, represents the angular acceleration, f s represents the structural natural frequency, c represents the chord length of the airfoil, and U ∞ represents the incoming wind speed, ζ represents the structural damping coefficient; C M represents the pitch moment coefficient of the airfoil; m represents the airfoil mass, ρ represents the fluid density; r represents the radius of gyration of the airfoil. It should be noted that in the above formula, only the angular displacement, angular velocity, angular acceleration and pitch moment coefficient are unknown variables, and the others are structural parameters of the airfoil and can be calculated using conventional methods in the field. For example, airfoil mass m = airfoil density * πr 2 / 4, r = c / 2; radius of gyration

[0059] In one embodiment, the structural motion equations include the pitch moment coefficient C M Other aerodynamic coefficients such as lift coefficient and drag coefficient can also be included according to the specific research problem.

[0060] In one implementation of the embodiment of the present application, the above step S102 may further include the following step S1021:

[0061] Step S1021, based on the turbulence model, the unsteady Reynolds time-averaged method is used to perform numerical simulation on the two-dimensional flow field to establish the following flow control equation:

[0062]

[0063] Among them, U i , U j They represent the fluid at point x at time t. i ,y i The velocity component at represents the average velocity of the fluid in the x direction, ρ represents density, p represents pressure, v represents viscosity, S ji The fluid at point x at time t i ,y i The strain velocity tensor at , represents the Reynolds stress term.

[0064] In one implementation of the present application, the second-order Crank-Nicolson method is used to solve the above structural motion equation to obtain an expression for the airfoil flutter angular displacement and its derivative:

[0065]

[0066] Rearranging the above expression, we get:

[0067]

[0068] Then substitute it into the structural motion equation in step S1012 to obtain the following coupling system equation:

[0069]

[0070] Among them, θ n , Respectively represent the angular displacement, angular velocity, and angular acceleration at time t, θ n+1 represents the angular displacement at time t+1, C Mn+1 Represents the pitching moment coefficient at time t+1.

[0071] In one implementation of the embodiment of the present application, the above step S104 may further include the following steps S1041 and S1042:

[0072] Step S1041, solving the flow control equation to obtain the pitch moment coefficient at time t.

[0073] In this embodiment, a CFD solver is used to solve the flow control equation in the above step S1021 to obtain flow field data, and the pitch moment coefficient at time t is calculated based on the flow field data. The pitch moment coefficient can be calculated based on the flow field data by referring to the method in the prior art or using the existing fluid mechanics calculation software, which will not be described in detail here.

[0074] Step S1042, iteratively solving the angular displacement at time t+1 according to the pitch moment coefficient at time t and the coupled system equation.

[0075] In this embodiment, see the attached Figure 3, solve the structural flutter response according to the CFD solver and the CSD solver. Specifically, the geometric parameters of CFD are the parameters of the fluid motion selected for study. The grid is generated to divide the flow field into many small grid points, and each grid point can be discretized to achieve the solution of the unsteady flow field and obtain the structural aerodynamic coefficients (such as the pitch moment coefficient). For the structural operation (motion) model, the CSD solver is used to solve it, and then the structural aerodynamic coefficients obtained by CFD are used as the input of the CSD solver to solve the structural motion equation, so as to achieve the flutter angular displacement at the current moment (t+1 moment) according to the flutter displacement at the previous moment (t moment). It should be noted that after obtaining the flutter angular displacement at the current moment, the flow field data at the next moment has also changed, so it is necessary to update the flow domain grid and then continue to solve the flutter angular displacement at the next moment. As an example, by compiling the grid deformation function, all grids are deformed at each time step, and the radial basis function interpolation method is used to update the position and velocity of the airfoil structure, and the iteration is continuously promoted to determine the flutter angular displacement of the blade. It can be understood that after the flutter angular displacement is obtained, the angular velocity and angular acceleration of the flutter can be further determined by taking derivatives.

[0076] In one implementation of the embodiment of the present application, after the above step S104, the following step S105 may be further included:

[0077] Step S105, performing structural optimization or fault analysis on the wind turbine blades according to the flutter value.

[0078] In this embodiment, after obtaining the flutter (response) value, the blade structure can be optimized, such as modifying the blade geometry, material selection, manufacturing process and other parameters to reduce the flutter value. After modifying the blade structure, the flutter value can be recalculated, and the influence of different flutter angles on the flutter response can be evaluated by comparing the flutter values ​​before and after the modification, so as to select a more optimal blade structure.

[0079] In one embodiment, after the flutter angle is determined, further simulation or experimentation may be performed to support fault analysis. As an example, fault features such as cracks, deformation, fatigue damage, etc. may be added to the simulation model, and then how these features affect the flutter response may be observed, thereby helping to identify potential causes of failure of the wind turbine blade.

[0080] This application achieves the purpose of predicting and analyzing the dynamic response characteristics of wind turbine blades (such as aerodynamic loads, flutter displacements, and surface stresses) at different wind speeds and angles of attack through a numerical simulation method that couples fluid dynamics and structural mechanics; and further achieves the purpose of optimizing blade design, improving its aeroelastic stability, and reducing failure rates. This method can be widely used in the design and operation of wind turbine blades and has certain engineering practical value.

[0081] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present application, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted schemes are equivalent to the technical schemes described in this application, and therefore will also fall within the scope of protection of this application.

[0082] Another aspect of the present application also provides a system for determining the flutter value of a wind turbine blade, such as Figure 4 As shown, the system includes: a first simulation module 401, which is used to establish a structural motion equation of flutter response according to the structure of the wind turbine blade; a second simulation module 402, which is used to perform numerical simulation on the two-dimensional flow field to establish a flow control equation; a third simulation module 403, which is used to establish a coupling system equation according to the structural motion equation and the flow control equation; and a solver module 404, which is used to solve the coupling system equation to obtain a flutter value.

[0083] It is understood by those skilled in the art that all or part of the processes in the method for implementing the above-mentioned embodiment of the present application can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0084] Another aspect of the present application also provides a computer-readable storage medium.

[0085] In an 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 above method embodiment, and the program can be loaded and run by a processor to implement the above method for determining the flutter value of a wind turbine blade. For ease of explanation, only the parts related to the embodiment of the present application are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present application. The computer-readable storage medium can be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiment of the present application is a non-temporary computer-readable storage medium.

[0086] Another aspect of the present application also provides a smart device.

[0087] In an embodiment of an intelligent device according to the present application, the intelligent device may include at least one processor; and a memory connected to the at least one processor in communication; 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 of the above embodiments is implemented. Figure 5 , Figure 5 FIG. 4 exemplarily shows that the memory 11 and the processor 12 are communicatively connected via a bus.

[0088] In some embodiments of the present application, the smart device may further include at least one sensor, and the sensor is used to sense information. The sensor is communicatively connected to any type of processor mentioned in the present application. Optionally, the smart device described in the present application may be, but is not limited to, a mobile phone, a tablet computer, a desktop, a laptop, a handheld computer, a notebook computer, a vehicle-mounted device, an ultra-mobile personal computer (UMPC), etc., and the embodiments of the present application are not limited to this.

[0089] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A method for determining the flutter value of a wind turbine blade, characterized in that: The method comprises: The structural motion equation of flutter response is established according to the structure of the wind turbine blade; Numerical simulation of two-dimensional flow field is performed to establish the flow control equations; Establishing a coupled system equation according to the structural motion equation and the flow control equation; The coupled system equations are solved to obtain flutter values.

2. The method according to claim 1, characterized in that: The flutter response includes the angular displacement, angular velocity, and angular acceleration of the wind turbine blade structure flutter. The structural motion equation of the flutter response is established according to the structure of the wind turbine blade, including: Simplifying the wind turbine blade into a two-dimensional airfoil with one rotational degree of freedom; A structural motion equation regarding the angular displacement, angular velocity and angular acceleration is established based on the structural parameters of the two-dimensional airfoil.

3. The method according to claim 2, characterized in that The structural motion equations about the angular displacement, angular velocity, and angular acceleration established based on the structural parameters of the two-dimensional airfoil are expressed as follows: k s =2πf s c / U ∞ μ=4m / (prc 2 ) Wherein, θ represents the angular displacement, represents the angular velocity, represents the angular acceleration, f s represents the structural natural frequency, c represents the chord length of the airfoil, U ∞ represents the incoming wind speed, ζ represents the structural damping coefficient; C M represents the pitching moment coefficient of the airfoil; m represents the mass of the airfoil, ρ represents the fluid density; r represents the radius of gyration of the airfoil.

4. The method according to claim 3, characterized in that The method of numerically simulating the two-dimensional flow field and establishing the flow control equation includes: Based on the turbulence model, the unsteady Reynolds time-averaged method is used to numerically simulate the two-dimensional flow field and establish the following flow control equation: Among them, U i , U j They represent the fluid at point x at time t. i ,y i The velocity component at represents the average velocity of the fluid in the x direction, ρ represents density, p represents pressure, v represents viscosity, S ji The fluid at point x at time t i ,y i The strain velocity tensor at , represents the Reynolds stress term.

5. The method according to claim 4, characterized in that The coupling system equation established according to the structural motion equation and the flow control equation is expressed as follows: Among them, θ n , Respectively represent the angular displacement, angular velocity, and angular acceleration at time t, θ n+1 represents the angular displacement at time t+1, C Mn+1 Represents the pitching moment coefficient at time t+1.

6. The method according to claim 5, characterized in that The step of solving the coupled system equation to obtain a flutter value includes: Solving the flow control equation to obtain the pitch moment coefficient at time t; The angular displacement at time t+1 is iteratively solved according to the pitch moment coefficient at time t and the coupling system equation.

7. The method according to claim 1, characterized in that The method further comprises: The structure of the wind turbine blade is optimized or fault analyzed according to the flutter value.

8. A system for determining the flutter value of a wind turbine blade, characterized in that: The system comprises: A first simulation module is used to establish a structural motion equation of a flutter response according to the structure of a wind turbine blade; The second simulation module is used to perform numerical simulation on the two-dimensional flow field and establish the flow control equation; A third simulation module is used to establish a coupled system equation according to the structural motion equation and the flow control equation; A solver module is used to solve the coupled system equations to obtain a flutter value.

9. A smart device, characterized in that: include: at least one processor; as well as a memory communicatively coupled to the at least one processor; The memory stores a computer program, and when the computer program is executed by the at least one processor, the method according to any one of claims 1 to 7 is implemented.

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

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