Single-axis photovoltaic tracking system and wind-induced vibration response simulation method

Abstract

The invention discloses a single-axis photovoltaic tracking system and a wind-induced vibration response simulation method, and the method comprises the steps: building a solid domain geometric model and a fluid domain geometric model based on the structure of the single-axis photovoltaic tracking system; performing dynamic mesh generation on the fluid domain geometric model, performing fluid domain transient analysis, and determining an aerodynamic load acting on the solid domain geometric model; performing transient structure analysis on the solid domain geometric model, and determining the pressure of the solid domain geometric model under the action of the aerodynamic load; carrying out bidirectional data exchange, solving the solid domain geometric model to obtain displacement, transmitting the displacement to the fluid domain geometric model based on a fluid-solid coupling surface, and carrying out repeated iteration through an interpolation method so as to solve fluid-solid coupling; and exporting rotation angle data of the single-axis photovoltaic tracking system, drawing a time domain rotation angle curve, obtaining the wind-induced vibration condition of the single-axis photovoltaic tracking system under the aerodynamic load of the fluid domain geometric model according to the time domain rotation angle curve, and obtaining the wind-induced vibration response characteristics of the system.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic supports, and particularly to a single-axis photovoltaic tracking system and a simulation method for wind-induced vibration response. Background Art

[0002] As a support structure for solar photovoltaic modules, the wind resistance performance of the photovoltaic support is crucial for the safety of the entire power station. To design a more stable and safe solar tracking system, and at the same time avoid material waste and cost increase caused by over-design, it is necessary to pre-evaluate the impact of wind loads on the solar tracking system and conduct a simulation of the wind-induced vibration response of the solar tracking system.

[0003] Currently, the simulation of the wind-induced vibration response of the solar single-axis photovoltaic tracking system is generally based on solid modal analysis and transient dynamics methods, without considering the influence of the fluid field on the solid; or, the wind field is analyzed through the fluid, without considering the influence of the solid deformation on the fluid field, which results in a deviation between the obtained vibration simulation results and the wind tunnel test results.

[0004] Therefore, how to improve the technical defects existing in the prior art has always been an urgent problem to be solved by those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of this application is to provide a single-axis photovoltaic tracking system and a simulation method for wind-induced vibration response, which consider the coupling effect that the fluid load acts on the solid to generate deformation, and the solid deformation in turn changes the fluid motion state, so as to obtain a more accurate simulation of the wind-induced vibration response and provide a more powerful scientific basis for the design of the single-axis photovoltaic tracking system.

[0006] The technical solution provided by the present invention is as follows:

[0007] A simulation method for the wind-induced vibration response of a single-axis photovoltaic tracking system, the single-axis photovoltaic tracking system includes a photovoltaic tracking support and photovoltaic modules arranged on the photovoltaic tracking support, and includes the following steps:

[0008] Based on the structure of the single-axis photovoltaic tracking system, establish a geometric model of the solid domain, and establish a geometric model of the fluid domain covering the geometric model of the solid domain;

[0009] Perform dynamic mesh division on the geometric model of the fluid domain, import the geometric model of the fluid domain with dynamic meshes into the fluent module for transient analysis of the fluid domain, and set boundary conditions for the geometric model of the fluid domain to determine the aerodynamic load acting on the geometric model of the solid domain;

[0010] Import the geometric model of the solid domain into the Transient Structural module for transient structural analysis, apply the aerodynamic load to the geometric model of the solid domain, and determine the pressure of the geometric model of the solid domain under the action of the aerodynamic load.

[0011] Perform two-way data exchange between the geometric model of the fluid domain and the geometric model of the solid domain. Solve the geometric model of the solid domain to obtain the displacement based on the pressure acting on the geometric model of the solid domain, and then transfer the displacement to the geometric model of the fluid domain based on the fluid-structure interaction surface. Iterate back and forth through the interpolation method to achieve the solution of fluid-structure interaction.

[0012] Export the rotation angle data of the single-axis photovoltaic tracking system, draw the time-domain rotation angle curve, and obtain the wind-induced vibration condition of the single-axis photovoltaic tracking system under the aerodynamic load of the geometric model of the fluid domain according to the time-domain rotation angle curve.

[0013] In some embodiments, setting the boundary conditions for the geometric model of the fluid domain includes:

[0014] Set the inlet boundary condition to velocity, set the wind type to gradient wind, set the outlet boundary condition to pressure, and set the walls on both sides of the channel formed by the inlet and outlet of the fluid domain to symmetric boundary conditions.

[0015] In some embodiments, importing the geometric model of the fluid domain with dynamic mesh into the fluent module for transient simulation of the fluid domain includes:

[0016] Select a pressure solver, an absolute velocity equation, and an RNG k-ε turbulence model for solution control.

[0017] In some embodiments, selecting the RNG k-ε turbulence model includes:

[0018] Set the turbulent kinetic energy k and the dissipation rate ε, and the inlet turbulent characteristic parameters all change with the change of height z.

[0019] In some embodiments, importing the geometric model of the fluid domain with dynamic mesh into the fluent module for transient simulation of the fluid domain further includes:

[0020] Activate the dynamic mesh, select a diffusion smoothing method to update the dynamic mesh in real time, and realize the change of the pressure of the geometric model of the fluid domain with time.

[0021] In some embodiments, importing the geometric model of the solid domain into the Transient Structural module for transient structural analysis includes:

[0022] Set the material, Young's modulus, and Poisson's ratio of the geometric model of the solid domain;

[0023] Set the first fluid-structure interaction surface of the fluid domain geometric model and the second fluid-structure interaction surface of the solid domain geometric model. The first fluid-structure interaction surface and the second fluid-structure interaction surface coincide, and the aerodynamic load acts on the solid domain geometric model through the first fluid-structure interaction surface and / or the second fluid-structure interaction surface.

[0024] Set the constraints of the solid domain geometric model.

[0025] Set the solution time and solution step size, and obtain the stress, deformation and rotation angle of the single-axis photovoltaic tracking system under the action of the aerodynamic load through iterative calculations.

[0026] In some embodiments, the second fluid-structure interaction surface is all the surfaces of the photovoltaic module.

[0027] In some embodiments, the grid sizes of the first fluid-structure interaction surface and the second fluid-structure interaction surface are the same.

[0028] In some embodiments, setting the constraints of the solid domain geometric model includes:

[0029] Fix one end of the main shaft of the single-axis photovoltaic tracking system to the ground for support, connect the middle of the main shaft to the ground with a revolute pair, and fixedly connect the photovoltaic module to the main shaft.

[0030] The present application also provides a single-axis photovoltaic tracking system, which is designed based on the single-axis photovoltaic tracking system wind-induced vibration response simulation method provided in any of the above embodiments.

[0031] The technical effects of the present application are as follows:

[0032] 1. The present application considers the coupling effect that the fluid load acts on the solid to cause deformation, and the solid deformation in turn changes the fluid motion state. By establishing the solid domain geometric model and the fluid domain geometric model of the single-axis photovoltaic tracking system structure and combining the fluid-structure coupling analysis method, the fluid-structure coupling wind-induced vibration response of the single-axis photovoltaic tracking system under the action of the aerodynamic load in the fluid domain geometric model can be accurately simulated, and more accurate wind-induced vibration response characteristics can be obtained, providing a more powerful scientific basis for the vibration suppression design of the single-axis photovoltaic tracking system, the selection of dampers, etc. While designing a more stable and safe photovoltaic tracking system, it can also avoid material waste and cost increase caused by over-design. In addition, the present application can also optimize parameters through numerical wind tunnel simulation without conducting wind tunnel tests, simulate the wind-induced vibration rotation angle result of the single-axis photovoltaic tracking system, reduce test costs, improve R & D efficiency, and provide a good foundation for the R & D and optimal design of the single-axis photovoltaic tracking system.

[0033] 2. In this application, a dynamic mesh is created on the geometric model of the fluid domain, and the diffusion smoothing method is selected to update the dynamic mesh in real time, enabling the dynamic mesh to change over time. This is beneficial for obtaining the pressure of the geometric model of the fluid domain through simulation calculations, and further obtaining the aerodynamic load acting on the geometric model of the solid domain, with high calculation accuracy and good effectiveness.

[0034] 3. In this application, the mesh sizes of the first fluid-structure coupling surface on the geometric model of the fluid domain and the second fluid-structure coupling surface on the geometric model of the solid domain are the same, which is beneficial for achieving two-way coupling through the first and second fluid-structure coupling surfaces, thereby simulating the wind-induced vibration of the single-axis photovoltaic tracking system. At the same time, when data between the geometric model of the fluid domain and the geometric model of the solid domain is transferred between the first and second fluid-structure coupling surfaces, it satisfies the principle of stress and displacement equality or conservation, enabling the solution of fluid-structure coupling, and thus obtaining the rotation angle data of the single-axis photovoltaic tracking system. This method not only improves the accuracy of simulating the rotation angle of the single-axis photovoltaic tracking system but also provides important guidance for the structural design and damper selection of the single-axis photovoltaic tracking system. Brief Description of the Drawings

[0035] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0036] Figure 1 is a flowchart of the method for simulating the wind-induced vibration response of a single-axis photovoltaic tracking system provided in an embodiment of this application;

[0037] Figure 2 is a diagram of the geometric model of the solid domain of the single-axis photovoltaic tracking system provided in an embodiment of this application;

[0038] Figure 3 is a diagram of the geometric model of the fluid domain of the single-axis photovoltaic tracking system provided in an embodiment of this application;

[0039] Figure 4 is Figure 2 the mesh division of the shown geometric model of the solid domain;

[0040] Figure 5 is Figure 3 the mesh division of the shown geometric model of the fluid domain;

[0041] Figure 6 is a curve graph of the rotation angle response of the single-axis photovoltaic tracking system provided in an embodiment of this application. Specific Embodiments

[0042] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific implementation methods of the present application will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other accompanying drawings and other implementation methods can be obtained based on these drawings without creative work.

[0044] In order to simplify the drawings, only the parts related to the present application are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0045] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0046] In this document, it should be noted that, unless otherwise clearly specified and limited, 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 a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various components of the present application are not absolute but relative. These descriptions are appropriate when these components are in the positions shown in the drawings. If the descriptions of the positions of these components change, the indications of these directions also change accordingly.

[0048] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0049] In view of the fact that the traditional simulation method for wind-induced vibration does not consider the coupling vibration effect, resulting in errors in the obtained simulation results, this application provides a simulation method for the wind-induced vibration response of a single-axis photovoltaic tracking system, which can simulate the actual wind field state, with more accurate calculation results and can accurately reflect the angular change of the single-axis photovoltaic tracking system.

[0050] In a specific embodiment, referring to Figure 1 , the simulation method includes the steps of: establishing a solid domain geometric model based on the structure of the single-axis photovoltaic tracking system, and establishing a fluid domain geometric model covering the solid domain geometric model; based on the fluid domain geometric model, determining the aerodynamic load acting on the solid domain geometric model; performing a transient structural analysis on the solid domain geometric model, applying the aerodynamic load to the solid domain geometric model, and determining the pressure on the solid domain geometric model under the action of the aerodynamic load; performing two-way data exchange between the fluid domain geometric model and the solid domain geometric model, solving the solid domain geometric model based on the pressure acting on the solid domain geometric model to obtain the displacement, and then transferring the displacement to the fluid domain geometric model based on the fluid-structure coupling surface, and iterating back and forth through the interpolation method to achieve the solution of the fluid-structure coupling; deriving the angular data of the single-axis photovoltaic tracking system, plotting the time-domain angular curve, and obtaining the wind-induced vibration condition of the single-axis photovoltaic tracking system under the aerodynamic load of the fluid domain geometric model according to the time-domain angular curve.

[0051] This embodiment considers the coupling effect that the fluid load acts on the solid to cause deformation, and the solid deformation in turn changes the fluid motion state. By establishing the solid domain geometric model and the fluid domain geometric model of the single-axis photovoltaic tracking system structure, and combining the fluid-structure coupling analysis method, it accurately simulates the fluid-structure coupling wind-induced vibration response of the single-axis photovoltaic tracking system under the action of the flow field aerodynamic load, so as to obtain more accurate wind-induced vibration response characteristics, and provide a more powerful scientific basis for the vibration suppression design of the single-axis photovoltaic tracking system, the selection of dampers, etc. In this way, while designing a more stable and safe photovoltaic tracking system, it is possible to avoid material waste and cost increase caused by over-design.

[0052] In practical applications, the fluid domain geometric model can be divided into dynamic grids, and the fluid domain geometric model with dynamic grids can be imported into the fluent module for fluid domain transient analysis, and boundary conditions can be set for the fluid domain geometric model to determine the aerodynamic load acting on the solid domain geometric model.

[0053] For example, referring to Figure 2 、 Figure 3 and Figure 5, using Workbench software, based on the structural dimensions of an actual single-axis photovoltaic tracking system, first establish the fluid domain geometric model and the solid domain geometric model of the single-axis photovoltaic tracking system in the DesignModeler or SpaceClaim module respectively. Of course, when establishing the fluid domain geometric model, the inlet and outlet surfaces of the fluid domain geometric model are also set. Then, in the Mesh module of Workbench software, mesh the fluid domain geometric model, and import the meshed fluid domain geometric model mesh into the fluent module of Workbench software. By setting the inlet velocity, pressure outlet, and ground roughness of the fluid domain geometric model, perform transient simulation on the flow field in the fluid domain geometric model to simulate the actual wind field environment. Next, set boundary conditions for the fluid domain geometric model. For example, set the inlet boundary condition as velocity, set the wind type as gradient wind, set the outlet boundary condition as pressure, and set the wall surfaces on both sides of the channel formed by the inlet and outlet of the fluid domain as symmetric boundary conditions, so as to determine the aerodynamic load acting on the solid domain geometric model.

[0054] Specifically, when importing the meshed fluid domain geometric model mesh into the fluent module of Workbench software, a pressure solver, an absolute velocity equation, and an RNG k-ε turbulence model should be selected for solution control. The RNG k-ε turbulence model can well simulate the fully turbulent flow process of the single-axis photovoltaic tracking system in the flow field, which is close to the actual flow field, and its calculation formula is as follows:

[0055]

[0056]

[0057] In the formula, k is the turbulent kinetic energy; ε is the turbulent dissipation; G k is the turbulent kinetic energy caused by the mean velocity gradient; G b is the generation of turbulent kinetic energy caused by buoyancy; R ε is the influence of compressible turbulent pulsation on the total dissipation rate.

[0058] When selecting the RNG k-ε turbulence model, it is necessary to set that the turbulent kinetic energy k, the dissipation rate ε, and the inlet turbulence characteristic parameters all change with the height z.

[0059] Subsequently, activate the dynamic mesh on the fluid domain geometric model, select the diffusion smoothing method to update the dynamic mesh in real time, so that the dynamic mesh changes with time, and realize the change of the pressure of the fluid domain geometric model with time. Then, in the transient simulation, divide each second into several time steps, obtain the pressure of the fluid domain geometric model through iterative calculation, and further obtain the aerodynamic load acting on the solid domain geometric model, with high calculation accuracy and good effectiveness.

[0060] The above real-time grid update equation is as follows:

[0061]

[0062] In the formula, s is the diffusion coefficient, is the movement speed of the grid, and Δ is the Laplace operator.

[0063] Among them, the diffusion coefficient s is calculated by the following formula:

[0064]

[0065] In the formula, d is the distance between the regularized grid node and the boundary, and α is the diffusion parameter.

[0066] In a specific embodiment, the Transient Structural module is imported into the solid domain geometric model for transient structural analysis, so as to apply the aerodynamic load to the solid domain geometric model and determine the pressure of the solid domain geometric model under the action of the aerodynamic load.

[0067] Specifically, first, based on the material properties of the photovoltaic tracking bracket and the photovoltaic module in the actual single-axis photovoltaic tracking system, the material, Young's modulus, and Poisson's ratio of the solid domain geometric model are set in Engineering Data. Then, the first fluid-structure coupling surface of the fluid domain geometric model and the second fluid-structure coupling surface of the solid domain geometric model are set, and the first fluid-structure coupling surface and the second fluid-structure coupling surface coincide. The aerodynamic load acts on the solid domain geometric model through the first fluid-structure coupling surface and / or the second fluid-structure coupling surface. Next, the constraints of the solid domain geometric model are set; finally, the solution time and the solution step size are set. Based on the conservation principle, the fluid-structure coupling solution is carried out through iterative calculations. When the displacement and stress tolerance values of the single-axis photovoltaic tracking system reach the convergence requirements, the flow field pressure and velocity distribution of the fluid domain geometric model, as well as the stress, deformation, and rotation angle of the single-axis photovoltaic tracking system under the action of the aerodynamic load are obtained.

[0068] Specifically, the first fluid-structure coupling surface is all the surfaces of the photovoltaic module in the fluid domain geometric model; the second fluid-structure coupling surface is all the surfaces of the photovoltaic module in the solid domain geometric model. Refer to Figure 4 and Figure 5 , the first fluid-structure coupling surface and the second fluid-structure coupling surface are respectively meshed through the Mesh module of the Workbench software. At the same time, it is ensured that the mesh sizes of the first fluid-structure coupling surface and the second fluid-structure coupling surface are the same, so as to achieve two-way coupling through the first fluid-structure coupling surface and the second fluid-structure coupling surface, thereby more accurately simulating the wind-induced vibration of the single-axis photovoltaic tracking system and improving the accuracy of the rotation angle simulation of the single-axis photovoltaic tracking system.

[0069] Further, when setting the constraints of the solid domain geometric model, the axis of the single-axis photovoltaic tracking system in the solid domain geometric model can be simplified as a shell element, and the constraints between the axis, the photovoltaic module, and the ground are established. That is, one end of the main axis of the single-axis photovoltaic tracking system is fixedly supported on the ground, the middle of the main axis is connected to the ground by a revolute pair, and the photovoltaic module is fixedly connected to the main axis.

[0070] Furthermore, the stress, deformation, and rotation angle of the single-axis photovoltaic tracking system under the action of the aerodynamic load are obtained through iterative calculations, which specifically include the steps: through the System Coupling module of the Workbench software, the two-way data exchange between the fluid-structure coupling surface of the fluid domain and the fluid-structure coupling surface of the solid domain is carried out by using the interpolation method, and then the solution of the fluid-structure coupling is realized. That is, the fluid equation and the solid equation are solved iteratively in sequence. First, the flow field distribution is obtained, and then the pressure obtained by the solution is transferred to the solid based on the fluid-structure coupling boundary, and the displacement of the solid is obtained by solving. Then, the displacement is transferred to the flow field based on the fluid-structure coupling boundary. This process is repeated iteratively until the tolerance values of the displacement and stress of the single-axis photovoltaic tracking system reach the convergence requirements, and the solutions of the flow field and the structural field are obtained.

[0071] Among them, when the data between the fluid domain and the solid domain are transferred between the coupling surfaces, the conservation principle needs to be satisfied. The establishment of the conservation principle on the fluid-structure coupling surface mainly includes three parts: the fluid control equation, the solid control equation, and the fluid-structure coupling equation. Considering that there is no heat exchange problem in the wind-induced vibration response problem of the single-axis photovoltaic tracking system, the energy equation is ignored.

[0072] The above-mentioned fluid control equations mainly include the mass control equation and the momentum control equation. The mass control equation is as follows:

[0073]

[0074] In the formula, t is time; ρ f is the fluid density; v is the fluid velocity vector.

[0075] The momentum control equation is as follows:

[0076]

[0077] In the formula, T f is the fluid shear stress tensor; f f is the fluid body force vector.

[0078] The above-mentioned solid control equation is as follows:

[0079]

[0080] In the formula, ρ s is the solid density; σ s is the solid Cauchy stress tensor; fs is the solid volume force vector; is the acceleration of the solid domain element.

[0081] The above fluid-structure interaction equations are as follows:

[0082]

[0083] In the formula, τ f and τ s are the fluid stress and the solid stress respectively; n f and n s are the fluid unit direction vector and the solid unit direction vector respectively; d f and d s are the fluid displacement and the solid deformation respectively.

[0084] When transferring data between the fluid domain and the solid domain across the coupling surface, it is necessary to satisfy the principle of equal or conserved stress and displacement. Through the fluid-structure interaction solution, the flow field pressure and velocity distribution in the fluid domain and the stress, strain, and rotation angle results of the single-axis photovoltaic tracking system can be obtained.

[0085] For the simulation method disclosed in this application, first, a three-dimensional model of the solid and fluid of the single-axis photovoltaic tracking system is established, then these models are precisely meshed, and then the Fluent and Transient Structural modules in ANSYS software are used for fluid dynamics and structure. The transient interaction process between the fluid domain and the solid domain is realized through the finite element method, and the coupled wind-induced vibration effect is processed by combining the fluid-structure interaction analysis method. Moreover, in the transient simulation of the above fluid domain geometric model and solid domain geometric model, by changing the parameter settings (for example, the flow field inlet velocity and pressure outlet, ground roughness, material properties of photovoltaic modules and photovoltaic tracking brackets, etc.), the wind-induced vibration simulation of the single-axis photovoltaic tracking system can be carried out for different brackets under various working conditions and postures, at different wind speeds, different tilting angles, and different sizes and lengths, overcoming the problem in the existing simulation technology that the wind-induced vibration of the single-axis photovoltaic tracking system under actual wind field conditions cannot be accurately simulated. The accuracy of the rotation angle simulation of the single-axis photovoltaic tracking system under various working conditions and postures is realized, the test cost is reduced, and the R & D efficiency is improved, providing a good foundation for the research and development and optimal design of the single-axis photovoltaic tracking system, and also providing important guidance for the structural design and damper selection of the single-axis photovoltaic tracking system, thereby improving the overall stability and reliability of the single-axis photovoltaic tracking system.

[0086] Specifically, referring to Figures 1 to 3 , taking a four-row 39.8-meter single-axis photovoltaic tracking system as an example, the wind-induced vibration response simulation method of the single-axis photovoltaic tracking system includes the following specific steps:

[0087] Step (1): According to the actual structural dimensions of the four-row 39.8-meter single-axis photovoltaic tracking system, establish the three-dimensional fluid domain geometric model (as shown in Figure 3 ) and the three-dimensional solid domain geometric model (as shown in Figure 2 ) of the single-axis photovoltaic tracking system with an inclination angle of 15° in the DesignModeler module. At the same time, create the inlet and outlet surfaces of the fluid domain and set all the surfaces of the photovoltaic modules as fluid-structure interaction surfaces.

[0088] Step (2): Mesh the three-dimensional fluid domain geometric model and the three-dimensional solid domain geometric model of the single-axis photovoltaic tracking system in the Mesh module respectively. Among them, referring to Figure 5 , the mesh size on the fluid-structure interaction surface in the fluid domain geometric model is 20 mm, and the remaining part is divided according to the mesh size of 100 mm. Referring to Figure 4 , the entire solid domain geometric model is divided according to the mesh size of 20 mm.

[0089] Step (3): Import the mesh of the fluid domain geometric model in step (2) into fluent, and select the pressure solver, absolute velocity equation, and RNG k-ε turbulence model for transient simulation of the fluid domain. Adopt the velocity inlet boundary condition (Velocity-inlet), set the velocity as the gradient wind through the expression, use the pressure outlet boundary condition (Pressure-out) at the outlet of the flow domain, use the symmetry boundary condition (Symmetry) for both the left and right walls, set the ground roughness to 0.1, and set the turbulent kinetic energy k and the dissipation rate ε at the same time. Since the inlet turbulence characteristic parameters change with the height z, these two parameters need to be edited with user-defined functions and use UDF (user-defined function).

[0090] Step (4): Create a dynamic mesh on the fluid-structure interaction surface of the fluid domain, select the diffusion smoothing method to update the dynamic mesh in real time, so as to realize the change of the flow field mesh with time; through the coupling algorithm, divide 3 s into 600 time steps in the transient simulation, with a time step of 0.005 s, and obtain the fluid domain pressure through iterative calculation, and then obtain the aerodynamic load of the flow field acting on the solid domain.

[0091] Step (5): Import the mesh of the solid domain geometric model in step (2) into the Transient Structural module. Set the relevant parameters of the solid material. Among them, the material of the shaft is the default structural steel of the system, and the material parameters of the photovoltaic module are: density is 415.3 kg / m3, Young's modulus is 1788 MPa, and Poisson's ratio is 0.3. Set all the faces of the solid structure photovoltaic module of the single-axis photovoltaic tracking system as the System Coupling Region. One end of the shaft in the single-axis photovoltaic tracking system is fixedly supported by the ground, the middle of the shaft is connected to the ground by a revolute joint, the photovoltaic module is fixedly connected to the shaft, set the solution time to 3 s, and the solution step size to 0.005 s. Through iterative calculations, obtain the stress, deformation, and rotation angle of the single-axis photovoltaic tracking system under the action of the aerodynamic load in the flow field.

[0092] Step (6): Through the System Coupling module of the Workbench software, perform two-way data exchange between the fluid-solid coupling surface created in the fluid domain and the fluid-solid coupling surface in the solid domain by interpolation method, and then realize the solution of fluid-solid coupling, that is, the fluid equation and the solid equation are iteratively solved in sequence. First, obtain the flow field distribution, then transfer the solved pressure to the solid based on the fluid-solid coupling boundary, solve the solid to obtain the displacement, and then transfer the displacement to the flow field based on the fluid-solid coupling boundary. Repeat this iteration until the displacement and stress tolerance values of the direct system reach the convergence requirements, and obtain the solutions of the flow field and the structural field.

[0093] Step (7): Read the solution results of the fluid-solid coupling obtained in step (6), export the rotation angle result data of the single-axis photovoltaic tracking system, and plot the rotation angle curve (as Figure 6 shown). According to this rotation angle curve, observe the wind-induced vibration of the single-axis photovoltaic tracking system under the aerodynamic load in the flow field, and then realize the simulation of the time-domain wind-induced vibration response.

[0094] This application also provides a single-axis photovoltaic tracking system, which is analyzed and designed based on the wind-induced vibration response simulation method of the single-axis photovoltaic tracking system provided in any of the above embodiments. It has low production cost, stable structure, and high wind resistance.

[0095] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0096] It should be noted that the above embodiments can be freely combined according to needs. The above is only the preferred embodiment of this application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. A simulation method for the wind-induced vibration response of a single-axis photovoltaic tracking system. The single-axis photovoltaic tracking system includes a photovoltaic tracking bracket and photovoltaic modules arranged on the photovoltaic tracking bracket, and is characterized in that It includes the following steps: Based on the structure of the single-axis photovoltaic tracking system, establish a solid domain geometric model, and establish a fluid domain geometric model covering the solid domain geometric model; Perform dynamic mesh division on the fluid domain geometric model, import the fluid domain geometric model with dynamic mesh into the fluent module for transient analysis of the fluid domain, and set boundary conditions for the fluid domain geometric model to determine the aerodynamic load acting on the solid domain geometric model; Import the solid domain geometric model into the Transient Structural module for transient structural analysis, apply the aerodynamic load to the solid domain geometric model, and determine the pressure of the solid domain geometric model under the action of the aerodynamic load; Perform two-way data exchange between the fluid domain geometric model and the solid domain geometric model. Based on the pressure acting on the solid domain geometric model, solve for the displacement of the solid domain geometric model, and then transfer the displacement to the fluid domain geometric model based on the fluid-structure interaction surface. Iterate back and forth through the interpolation method to achieve the solution of fluid-structure interaction; Export the rotation angle data of the single-axis photovoltaic tracking system, draw the time-domain rotation angle curve, and obtain the wind-induced vibration condition of the single-axis photovoltaic tracking system under the aerodynamic load of the fluid domain geometric model according to the time-domain rotation angle curve.

2. The simulation method for wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 1, characterized in that The setting of boundary conditions for the fluid domain geometric model includes: Set the inlet boundary condition as velocity, set the wind type as gradient wind, set the outlet boundary condition as pressure, and set the wall surfaces on both sides of the channel formed by the inlet and outlet of the fluid domain as symmetric boundary conditions.

3. The simulation method for wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 2, wherein The importing of the fluid domain geometric model with dynamic mesh into the fluent module for transient simulation of the fluid domain includes: Select a pressure solver, an absolute velocity equation, and an RNG k-ε turbulence model for solution control.

4. The simulation method for wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 3, characterized in that, The selection of the RNG k-ε turbulence model includes: Set the turbulent kinetic energy k and the dissipation rate ε. The inlet turbulent characteristic parameters all change with the change of height z.

5. The method for simulating the wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 3, wherein The importing of the fluid domain geometric model with dynamic mesh into the fluent module for transient simulation of the fluid domain further includes: Activate the dynamic mesh, select the diffusion smoothing method to update the dynamic mesh in real time, and realize the change of the pressure of the fluid domain geometric model with time.

6. The simulation method for the wind-induced vibration response of the single-axis photovoltaic tracking system according to any one of claims 1-5, characterized in that, The importing of the solid domain geometric model into the Transient Structural module for transient structural analysis includes: Set the material, Young's modulus, and Poisson's ratio of the solid domain geometric model; Set the first fluid-structure interaction surface of the fluid domain geometric model and the second fluid-structure interaction surface of the solid domain geometric model. The first fluid-structure interaction surface and the second fluid-structure interaction surface coincide, and the aerodynamic load acts on the solid domain geometric model through the first fluid-structure interaction surface and / or the second fluid-structure interaction surface; Set the constraints of the solid domain geometric model; Set the solution time and the solution step size, and obtain the stress, deformation, and rotation angle of the single-axis photovoltaic tracking system under the action of the aerodynamic load through iterative calculations.

7. The method for simulating the wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 6, characterized in that The second fluid-structure interaction surface is all the surfaces of the photovoltaic module.

8. The method for simulating the wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 7, wherein The mesh sizes of the first fluid-structure interaction surface and the second fluid-structure interaction surface are the same.

9. The method for simulating the wind-induced vibration response of the single-axis photovoltaic tracking system according to claim 6, wherein The constraints for setting the geometric model of the solid domain include: Fix one end of the main shaft of the uniaxial photovoltaic tracking system to the ground support, connect the middle of the main shaft to the ground through a rotary pair, and fixedly connect the photovoltaic module to the main shaft.

10. A single-axis photovoltaic tracking system, characterized in that, Designed based on the method for simulating the wind-induced vibration response of the uniaxial photovoltaic tracking system according to any one of claims 1-9.

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