Methods, systems, control devices, and readable storage media for simulating wake in wind farms

Abstract

This invention relates to the field of wind farm control technology, specifically providing a method, system, control device, and readable storage medium for simulating wind farm wakes. The aim is to address how to obtain more accurate simulation results while maintaining computational speed during wind farm wake simulation. To this end, this invention obtains the wind shear factor of the wind farm based on the undisturbed wind speed and undisturbed total turbulence intensity at the hub height, and corrects the boundary conditions of the wind farm based on the wind shear factor. Furthermore, it applies the corrected boundary conditions and k-ε-f... P A turbulence model is used to simulate the wake of a wind farm. Using the above configuration, this invention applies k-ε-f. P When simulating wind farm wakes using turbulence models, the influence of wind shear on the wind farm boundary conditions is taken into account, making the simulation process more consistent with the actual situation of wind farms. This allows for the application of k-ε-f while ensuring computational speed. P Turbulence models provide more accurate wake simulation results for wind farms.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind farm control, and particularly provides a wind farm wake simulation method and system, a control device and a readable storage medium. BACKGROUND

[0002] With the development of wind power technology, the development and utilization of wind energy are also more and more extensive. In the application of wind farms, due to the influence of wind turbine wakes, it will cause greater energy loss in the wind farm, increase the turbulence intensity, and possibly reduce the fatigue life of downstream wind turbines. Therefore, it is necessary to establish a reliable engineering model to simulate the influence of wind turbine wakes in the wind farm. Large eddy simulation (LES) and Reynolds average Navier-Stokes (RANS) are two main wake simulation methods. Large eddy simulation aims to directly simulate large-scale eddies by using non-steady Navier-Stokes equations, and small-scale eddies are considered by using an approximate model. Compared with the direct simulation method, the calculation time is greatly reduced. However, because the calculation cost is still high, there is still a long way to go to be applied in engineering. The Reynolds average Navier-Stokes method is widely used in engineering due to its low calculation cost and wide application range.

[0003] The standard k-ε turbulence model, which is widely used in the Reynolds average Navier-Stokes method, is based on the Boussinesq assumption and can only predict isotropic turbulence, and cannot describe the anisotropic turbulence existing in the wind turbine wake. Many scholars have improved the standard turbulence model. Apsley et al. proposed a cubic form of nonlinear eddy viscosity model (NLEVM) to replace the standard k-ε turbulence model. Instead of using the traditional Boussinesq assumption, the model is based on a nonlinear stress-strain relationship, and the empirical constant C u is changed to a variable dependent on the flow, and the product of the velocity gradient exists in the model. It is found through simulation tests that the wind turbine wake loss predicted by the nonlinear model is closer to the large eddy simulation and the measured results, but numerical instability occurs at high turbulence levels.

[0004] van der Laan et al. simplified the above nonlinear turbulence model by ignoring the nonlinear term in the stress-strain relationship, and proposed a k-ε-f P turbulence model. Compared with the k-ε turbulence model, the model is simpler and only needs to calibrate the constant C RVan der Laan et al. used k-ε turbulence model to simulate the wake of 8 single wind turbines, and the results were very close to the results of large eddy simulation and field measurement. In the calculation process, the initial field roughness used was converted from the total turbulence intensity at the hub height without disturbance, rather than the actual roughness. In the conversion, the formula for calculating the turbulent kinetic energy according to the turbulence intensity was derived from the wind tunnel test, and the inflow of the wind tunnel test can be regarded as uniform inflow, that is, the inflow wind speed does not change with height. However, the wind profile of the actual wind farm and the initial field of CFD (Computational Fluid Dynamics) calculation are both with wind shear, which is contrary to the theory. Through calculation, it is found that the wind shear of the single wind turbine example used in the article of van der Laan is small; at the same time, when using k-ε-f P turbulence model to calculate the wake velocity deficit of other wind turbines with larger wind shear, it is found that the calculation results are quite different from the results of large eddy simulation and field measurement.

[0005] Correspondingly, there is a need in the art for a new wind farm wake simulation scheme to solve the above problems. SUMMARY

[0006] In order to overcome the above defects, the present application is proposed to provide a solution or at least partially solve the problem of how to obtain more accurate simulation results while considering the calculation speed when simulating the wake of a wind farm.

[0007] In a first aspect, the present application provides a wind farm wake simulation method, comprising:

[0008] According to the undisturbed wind speed and undisturbed total turbulence intensity at the hub height of the wind farm, obtaining the wind shear factor of the wind farm;

[0009] According to the wind shear factor, correcting the boundary conditions of the wind farm;

[0010] According to the corrected boundary conditions, applying k-ε-f P turbulence model to simulate the wake of the wind farm.

[0011] In one technical solution of the above wind farm wake simulation method, the step of "obtaining the wind shear factor of the wind farm according to the undisturbed wind speed and undisturbed total turbulence intensity at the hub height of the wind farm" comprises:

[0012] According to the undisturbed total turbulence intensity at the hub height of the wind farm, obtaining the initial fitting roughness of the wind farm;

[0013] According to the undisturbed wind speed at the hub height of the wind farm and the initial fitting roughness, a wind shear factor of the wind farm is obtained.

[0014] In one of the technical solutions of the wake simulation method of the wind farm, the step of obtaining the initial fitting roughness according to the undisturbed total turbulence intensity at the hub height of the wind farm comprises obtaining the initial fitting roughness according to the following formula:

[0015]

[0016] wherein z 0_0 is the initial fitting roughness; H ref is the hub height; κ is the von Karman constant; Ix ，∞ is the undisturbed total turbulence intensity at the hub height, C u is a model constant.

[0017] In one of the technical solutions of the wake simulation method of the wind farm, the step of obtaining the wind shear factor of the wind farm according to the undisturbed wind speed at the hub height of the wind farm and the initial fitting roughness comprises:

[0018] According to the undisturbed wind speed at the hub height of the wind farm, and according to the following formula, the wind speed at the top of the wind wheel and the wind speed at the bottom of the wind wheel are obtained:

[0019]

[0020]

[0021] wherein U up is the wind speed at the top of the wind wheel; U down is the wind speed at the bottom of the wind wheel; U H，∞ is the undisturbed wind speed at the hub height; D is the diameter of the wind wheel.

[0022] According to the wind speed at the top of the wind wheel and the wind speed at the bottom of the wind wheel, and according to the following formula, the wind shear factor is obtained:

[0023] γ=(U up -U down ) / D

[0024] wherein γ is the wind shear factor.

[0025] In one of the technical solutions of the wake simulation method of the wind farm, the boundary conditions comprise the fitting roughness and the turbulent kinetic energy of the wind farm, and the step of correcting the boundary conditions of the wind farm according to the wind shear factor comprises:

[0026] According to the wind shear factor, a wind shear correction value of the wind farm is obtained;

[0027] According to the wind shear correction value, a fitted roughness and a turbulent kinetic energy of the wind farm of the wind farm are corrected.

[0028] In one of the technical solutions of the above-mentioned wind farm wake simulation method, the step of "obtaining a wind shear correction value of the wind farm according to the wind shear factor" comprises:

[0029] The wind shear correction value is obtained according to the following formula:

[0030]

[0031] Wherein, f (γ) is the wind shear correction value, and γ is the wind shear factor.

[0032] In one of the technical solutions of the above-mentioned wind farm wake simulation method, the step of "correcting the fitted roughness and the turbulent kinetic energy of the wind farm of the wind farm according to the wind shear correction value" comprises:

[0033] The corrected fitted roughness is obtained according to the wind shear correction value and according to the following formula:

[0034]

[0035] Wherein, z0 is the corrected fitted roughness; H ref is the hub height; κ is the von Karman constant; I H，∞ is the undisturbed total turbulence intensity at the hub height, C u is the model constant;

[0036] The corrected turbulent kinetic energy is obtained according to the corrected fitted roughness and the wind shear correction value according to the following formula:

[0037]

[0038] Wherein, k is the corrected turbulent kinetic energy; I H，∞ is the undisturbed total turbulence intensity at the hub height; U H，∞ is the undisturbed wind speed at the hub height.

[0039] In the second aspect, the present application provides a wind farm wake simulation system, characterized in that the system comprises:

[0040] A wind shear factor acquisition module configured to obtain a wind shear factor of the wind farm according to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm;

[0041] a wind farm boundary condition correction module configured to correct boundary conditions of the wind farm according to the wind shear factor;

[0042] a wake simulation module configured to simulate a wake of the wind farm according to the corrected boundary conditions and the k-ε-f P turbulence model.

[0043] In a third aspect, a control device is provided, which includes a processor and a storage device adapted to store a plurality of program codes adapted to be loaded and run by the processor to perform the wind farm wake simulation method according to any one of the technical solutions of the wind farm wake simulation method.

[0044] In a fourth aspect, a computer readable storage medium is provided, which has stored therein a plurality of program codes adapted to be loaded and run by a processor to perform the wind farm wake simulation method according to any one of the technical solutions of the wind farm wake simulation method.

[0045] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0046] In the implementation of the technical solutions of the present application, the wind shear factor of the wind farm is obtained according to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm, and the boundary conditions of the wind farm are corrected according to the wind shear factor, and the corrected boundary conditions and the k-ε-f P turbulence model are further applied to simulate the wake of the wind farm. Through the above configuration, the k-ε-f P turbulence model is applied to simulate the wake of the wind farm, and the influence of wind shear on the boundary conditions of the wind farm is considered, so that the simulation process is more in line with the actual situation of the wind farm, and the k-ε-f P turbulence model is applied to simulate the wake of the wind farm, and the influence of wind shear on the boundary conditions of the wind farm is considered, so that the simulation process is more in line with the actual situation of the wind farm, and the k-ε-f BRIEF DESCRIPTION OF DRAWINGS

[0047] The disclosure of the present application will become more apparent from the following description in conjunction with the accompanying drawings. It is easily understood by those skilled in the art that the drawings are only for the purpose of illustration, and are not intended to limit the scope of protection of the present application. Among them:

[0048] Figure 1 is a main step flow diagram of the wind farm wake simulation method according to an embodiment of the present application;

[0049] Figure 2is a main step flow diagram of modifying the roughness and the turbulent kinetic energy of a wind farm according to an embodiment of the present application;

[0050] Figure 3 is a comparison diagram of wake simulation results according to an embodiment of the present application and wake simulation results in the prior art;

[0051] Figure 4 is a main structure block diagram of a wake simulation system of a wind farm according to an embodiment of the present application. DETAILED DESCRIPTION

[0052] Some embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that the 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.

[0053] In the description of the present application, "module" and "processor" can include hardware, software or a combination of both. A module can include hardware circuit, various suitable sensors, communication port, memory, and can also include software part such as program code, and can be a combination of software and hardware. The processor can be a central processing unit, microprocessor, digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor can be implemented in software, hardware or a combination of both. The non-transitory computer readable storage medium includes any suitable medium that can store program code, such as magnetic disk, hard disk, optical disk, flash memory, read-only memory, random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B or both A and B. The term "at least one of A or B" or "at least one of A and B" has similar meaning as "A and / or B", and can include only A, only B or both A and B. The singular form of the term "one", "this" can also include plural forms.

[0054] First, the k-ε-f P The turbulent flow model is described.

[0055] The k-ε-f P The turbulent flow model uses the same stress-strain relationship and k-ε transport equation as the k-ε turbulent flow model, and the stress-strain relationship is determined according to the following formula (1):

[0056]

[0057] wherein, is the Reynolds stress, k is the turbulent kinetic energy, δ i，j is the Kronecker number, v T is the turbulent viscosity coefficient, Ui，j This represents the average velocity gradient.

[0058] The k-ε transport equation is determined according to the following formula (2):

[0059]

[0060] Among them, v T C is the turbulent viscosity coefficient, P is the turbulence generation rate, and C is the turbulence viscosity coefficient. ε，1 C ε，2 , σ k , σ ε These are model constants.

[0061] k-ε-f P v in turbulence model T It is obtained according to the following formula (3):

[0062]

[0063] ε is the turbulent dissipation rate, C u * C is a flow-based parameter and can be obtained from the following formula (4). u * :

[0064] C u * =C u f P (4)

[0065] Among them, f P f is a scalar function used to simulate the effects of non-equilibrium flow conditions. f can be obtained from the following formula (5). P :

[0066]

[0067] Wherein, P / ε and These represent the ratios of turbulence generation and dissipation in actual and standard flows, respectively. Directly using formula (5) would lead to numerical instability; therefore, an approximation is made, allowing P / ε≈f. P C u σ 2 ,and Substituting into formula (5) yields formula (6):

[0068]

[0069] Among them, C R This is the Rotta constant, taken as 4.5 for wake simulation. Shear parameter. The degree of local flow deviation from the logarithmic law region of simple shear flow is quantified. In the equilibrium state of flow, the shear parameter That is f P =1, at which the k-ε-f P turbulence model is the standard k-ε turbulence model; when f P <1, the C u * < C u , at which the turbulent viscosity coefficient v T is reduced, and the dissipation rate of turbulent kinetic energy at high shear parameter is reduced.

[0070] In the present embodiment, the k-ε-f P turbulence model has the related constants as shown in Table 1.

[0071] Table 1 k-ε-f P turbulence model related model constant table

[0072] C R ]]> C u ]]> C ε，1 ]]> C ε，2 ]]> k ]]> ​ ε ]]> ​ Kappa 4.5 0.033 1.21 1.92 1.00 1.30 0.40

[0073] According to the IEC61400-1 standard, the relationship of the components of the turbulent intensity in three directions can be expressed by the following formula (7) and formula (8):

[0074]

[0075]

[0076] If the undisturbed total flow turbulent intensity Iu ，H，∞ at the hub height is known, the undisturbed total turbulent intensity I H，∞ at the hub height of the wind turbine can be calculated, which is the turbulent intensity to be used for calculating the initial boundary condition, and is specifically shown in the following formula (9):

[0077]

[0078] The wind profile at the inlet is in logarithmic form, as shown in the following formula (10):

[0079]

[0080] Wherein, U is the wind speed at height z, u * is the friction velocity, κ is the model constant, which is 0.4, and z0 is the fitting roughness.

[0081] The turbulent kinetic energy k can be calculated according to the following formula (11):

[0082]

[0083] The formula (9), the formula (10), the formula (11) are associated, that is, the relationship formula of the total turbulence intensity, the turbulent kinetic energy and the fitted roughness at the hub height can be obtained, as shown in the formula (12)

[0084]

[0085] Wherein, U H，∞ is the wind speed at the hub height zH.

[0086] The fitted roughness z0 can be calculated according to the following formula (13):

[0087]

[0088] Thus, in the application of k-ε-f P When the wind farm is simulated by the k-ε-f H The wind speed and the total turbulence intensity at the hub height zH are known, and the turbulent kinetic energy and the fitted roughness of the initial field can be calculated, and the turbulent kinetic energy and the fitted roughness of the wind farm can be used as the boundary conditions of the initial field entrance to realize the wake simulation of the wind farm. However, the turbulent kinetic energy and the fitted roughness obtained by the above method are derived by applying wind tunnel test, and the process does not consider the influence of wind shear on the initial field, so the boundary conditions are not accurate, which further leads to inaccurate results of the k-ε-f P The k-ε-f

[0089] The prior art needs a new wind farm wake simulation scheme to solve the above problems.

[0090] Referring to the accompanying drawings Figure 1 , Figure 1 The main step flowchart of the wind farm wake simulation method according to an embodiment of the present application is shown in FIG. 1. As shown in FIG. 1, the wind farm wake simulation method in the embodiment of the present application mainly includes the following steps S101-S103. Figure 1

[0091] Step S101: According to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm, the wind shear factor of the wind farm is obtained.

[0092] In the embodiment, the wind shear factor of the wind farm can be calculated according to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm. The wind shear factor is a parameter reflecting the change of the wind direction, the wind speed and the like in the control horizontal and / or vertical distance.

[0093] Step S102: According to the wind shear factor, the boundary conditions of the wind farm are corrected.

[0094] ​In the embodiment, the boundary condition of the wind farm can be corrected according to the wind shear factor.

[0095] In one embodiment, the boundary condition of the wind farm can include the fitting roughness and the turbulent kinetic energy of the wind farm, that is, the fitting roughness and the turbulent kinetic energy of the wind farm can be corrected according to the wind shear factor, so that the fitting roughness and the turbulent kinetic energy of the wind farm can reflect the wind shear of the wind farm. The roughness of the wind farm is a parameter for measuring the friction of the ground to the wind. The fitting roughness is the roughness of the wind farm obtained by conversion, and is generally calculated according to the undisturbed total turbulence intensity at the hub height.

[0096] Step S103: applying the k-ε-f P The turbulence model is used to simulate the wake of the wind farm.

[0097] In the embodiment, the corrected boundary condition can be applied, and the k-ε-f P The turbulence model is used to simulate the wake of the wind farm.

[0098] In one embodiment, the corrected fitting roughness and the turbulent kinetic energy can be applied as the boundary condition, and the k-ε-f P The turbulence model is used to simulate the wake of the wind farm, and a more accurate simulation result of the wake can be obtained.

[0099] Based on the steps S101-S103, the wind shear factor of the wind farm is obtained according to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm, the boundary condition of the wind farm is corrected according to the wind shear factor, and the corrected boundary condition and the k-ε-f P The turbulence model is used to simulate the wake of the wind farm. Through the above configuration, the k-ε-f P The turbulence model takes into account the influence of the wind shear on the boundary condition of the wind farm when simulating the wake of the wind farm, so that the simulation process is more in line with the actual situation of the wind farm, and the k-ε-f P The turbulence model is used to simulate the wake of the wind farm, and the accuracy of the simulation result is higher.

[0100] The steps S101 and S102 will be further described below.

[0101] In one embodiment of the embodiment of the application, the step S101 can further include the following steps S1011 and S1012:

[0102] Step S1011: obtaining the initial fitting roughness of the wind farm according to the undisturbed total turbulence intensity at the hub height of the wind farm.

[0103] In the embodiment, similar to formula (13), the initial fitting roughness can be obtained according to the following formula (14):

[0104]

[0105] wherein z 0_0 is the initial fitting roughness; H ref is the hub height; κ is the von Karman constant; I H，∞ is the undisturbed total turbulence intensity at the hub height, C u is a model constant.

[0106] Step S1012: obtaining the wind shear factor of the wind farm according to the undisturbed wind speed at the hub height of the wind farm and the initial fitting roughness.

[0107] In the embodiment, step S1012 can further include step S10121 and step S10122:

[0108] Step S10121: obtaining the wind speed at the upper vertex of the wind wheel and the wind speed at the lower vertex of the wind wheel according to the undisturbed wind speed at the hub height of the wind farm and according to the following formula (15) and formula (16):

[0109]

[0110]

[0111] wherein U up is the wind speed at the upper vertex of the wind wheel; U down is the wind speed at the lower vertex of the wind wheel; U H，∞ is the undisturbed wind speed at the hub height; D is the diameter of the wind wheel.

[0112] Step S10122: obtaining the wind shear factor according to the wind speed at the upper vertex of the wind wheel and the wind speed at the lower vertex of the wind wheel and according to the following formula (17):

[0113] γ=(U up -U down ) / D (17)

[0114] wherein γ is the wind shear factor.

[0115] In one embodiment of the embodiment of the application, step S102 can further include the following step S1021 and step S1022:

[0116] Step S1021: obtaining the wind shear correction value of the wind farm according to the wind shear factor.

[0117] In the embodiment, the wind shear correction value can be obtained according to the following formula (18):

[0118]

[0119] wherein f(γ) is the wind shear correction value, and γ is the wind shear factor

[0120] Step S1022: correcting the fitted roughness and the turbulent kinetic energy of the wind farm of the wind farm according to the wind shear correction value.

[0121] In the embodiment, the step S1022 can further include the following step S10221 and step S10222:

[0122] Step S10221: obtaining the corrected fitted roughness according to the wind shear correction value and according to the following formula (19):

[0123]

[0124] wherein z0 is the corrected fitted roughness; H ref is the hub height; κ is the von Karman constant; I H，∞ is the undisturbed total turbulence intensity at the hub height, and C u is the model constant.

[0125] Step S10222: obtaining the corrected turbulent kinetic energy according to the corrected fitted roughness and the wind shear correction value and according to the following formula (20):

[0126]

[0127] wherein k is the corrected turbulent kinetic energy; I H，∞ is the undisturbed total turbulence intensity at the hub height; U H，∞ is the undisturbed wind speed at the hub height.

[0128] After the corrected fitted roughness and the corrected turbulent kinetic energy are obtained through the formula (19) and the formula (20), the corrected fitted roughness and the corrected turbulent kinetic energy can be used as the boundary conditions of the initial field, the corrected fitted roughness can be substituted into the formula (10) to obtain the wind profile at the entrance of the wind farm, and the corrected turbulent kinetic energy can be substituted into the formula (3) to obtain the molecular motion viscosity, and then the k-ε-f P turbulence model is applied to simulate the wake of the wind farm.

[0129] In one embodiment, reference can be made to the accompanying Figure 2 , Figure 2is a schematic diagram of main steps of modifying the fitted roughness and turbulent kinetic energy of a wind farm according to an embodiment of the present application. As shown in Figure 2 , when modifying the fitted roughness and turbulent kinetic energy of a wind farm, the following steps can be taken:

[0130] Obtaining the hub height H ref and the total turbulence intensity without disturbance at the hub height I H，∞ ; calculating the initial fitted roughness z ref according to H H，∞ and I 0_0 ; calculating the wind speed at the upper and lower vertices of the wind wheel U H，∞ , U 0_0 according to the wind speed without disturbance at the hub height U up , the direct distance of the wind wheel D and z down ; calculating the wind shear factor γ according to U up , U down and D; calculating the wind shear correction value f(γ) according to γ; calculating the modified turbulent kinetic energy k according to the wind shear correction value, I H，∞ and U H，∞ ; and calculating the modified fitted roughness z0according to the wind shear correction value and H ref .

[0131] In one example, the wake simulation method of a wind farm according to an embodiment of the present application is applied to simulate the wake of a SWIFT wind turbine. In this example, the simulation is performed using the OpenFOAM platform. It should be emphasized that the OpenFOAM platform is only used as an example, and other simulation platforms such as EllipSys can also be used. In this example, the wake simulation of the wind farm can be performed according to the following steps S201 to S206:

[0132] Step S201: Setting the boundary conditions of the wind farm.

[0133] The relevant model constants in the -ε-f P turbulence model can be set according to Table 1.

[0134] The parameters of the wind turbine can be set according to Table 2.

[0135] Table 2: Parameters required for simulation of SWIFT wind turbine

[0136]

[0137] The hub height of the wind turbine can be set to 32.1 m and the wind speed without disturbance at the hub height can be set to 8.7 m / s in the 0 folder.

[0138] The initial fitted roughness of the wind farm can be calculated according to formula (14) as follows:

[0139]

[0140] The wind speeds at the top and bottom apexes of the wind turbine can be calculated using formulas (15) and (16):

[0141]

[0142]

[0143] The wind shear factor can be calculated using formula (17):

[0144]

[0145] The wind shear correction value can be calculated using formula (18):

[0146]

[0147] The corrected fitting roughness can be calculated using formula (19):

[0148]

[0149] The corrected turbulent kinetic energy can be calculated using formula (20):

[0150]

[0151] Step S202: Set the computing domain information.

[0152] Set the computational domain size to 800×600×300 (m);

[0153] The number of grids in the three directions is set to 80, 60, and 30 respectively, that is, the size of a single grid is 10×10×10 (m);

[0154] The thickness of the bottom mesh and the expansion coefficient of the mesh elements are calculated based on the corrected fitted roughness, wherein the thickness of the bottom mesh y is calculated according to the following formula (21). f :

[0155] y f =40Z0=40×0.000016=0.00064(m) (21)

[0156] Bottom mesh thickness y f The relationship between the computational domain height and the computational domain height is shown in the following formula (22):

[0157]

[0158] wherein q is the scale factor of the stretched grid, z is the vertical distance of the calculation domain, s z is the number of grid in z direction, the scale factor q of the stretched grid can be calculated as q≈1.52.

[0159] The grid cell expansion rate coefficient a can be calculated according to the following formula (23):

[0160]

[0161] Step S203: setting up the encryption network.

[0162] The size of the area that needs to be refined is set, and the two vertices of the lower left and the upper right are set as (100, 200, 10) and (600, 400, 80) (m) respectively; the direction that needs to be refined is set, and the grid in the x and y directions is selected to be encrypted by one time.

[0163] Step S204: setting up the brake disc information.

[0164] The actuator disc area range is set: the disc thickness is 15 m, the radius is 13.5 m of the wind wheel radius, and the center point is located at (200, 300, 32.1) (m); the inflow point position for calculating the wind speed, the wind wheel area and the thrust coefficient are set. The inflow point position is set to be 50 m in front of the actuator disc center point, i.e. (150, 300, 32.1) (m). The wind wheel area is obtained according to the following formula (24):

[0165] A=πR 2 =3.14159×13.5 2 =572.55(m 2 ) (24)

[0166] The thrust coefficient C t is set to be 0.81.

[0167] Step S205: setting up the information related to the SIMPLE algorithm.

[0168] The convergence values of the pressure, the velocity and the turbulent kinetic energy dissipation rate are set to be 10 -3 ; the selected turbulent model and the model constant are set, and the k-ε-f P turbulent model is selected as the turbulent model.

[0169] Step S206: post-processing the flow field information.

[0170] The flow field point information that needs to be obtained is set; the flow field information is obtained by using the post-processing software; and the wake velocity in the flow field information is normalized.

[0171] The attached Figure 3 , Figure 3is a comparison diagram of wake simulation results according to an embodiment of the present application and wake simulation results in the prior art, Figure 3 are wake simulation results of distances x=3D, x=4D and x=5D (D is the diameter of a wind turbine) between wind turbines respectively, wherein 1 is a k-ε-f P turbulence model simulation result, 2 is an embodiment simulation result of the present application, 3 is a LES simulation result, and 4 is an actual measurement result. As shown in Figure 3 , the wake simulation result obtained by using the wake simulation method of the wind farm according to the embodiment of the present application is closer to the k-ε-f P turbulence model simulation result than the LES model wake simulation result.

[0172] It should be noted that although the above embodiment describes each step in a specific order, those skilled in the art can understand that, in order to achieve the effect of the present application, the different steps do not have to be executed in such an order, and they can be executed simultaneously (in parallel) or in other orders, and these changes are within the protection scope of the present application.

[0173] Further, the present application also provides a wind farm wake simulation system.

[0174] Referring to the accompanying Figure 4 , Figure 4 is a main structure block diagram of a wind farm wake simulation system according to an embodiment of the present application. As shown in Figure 4 , the wind farm wake simulation system in the embodiment of the present application can include a wind shear factor acquisition module, a wind farm boundary condition correction module and a wake simulation module. In the embodiment, the wind shear factor acquisition module can be configured to acquire a wind shear factor of the wind farm according to an undisturbed wind speed and an undisturbed total turbulence intensity at a hub height of the wind farm. The wind farm boundary condition correction module can be configured to correct a boundary condition of the wind farm according to the wind shear factor. The wake simulation module can be configured to apply a k-ε-f P turbulence model to the wind farm for wake simulation.

[0175] The wind farm wake simulation system described above is used to execute Figure 1 As shown in the embodiment of the wind farm wake simulation method, the technical principles, the technical problems solved and the technical effects generated are similar, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related description of the wind farm wake simulation system can refer to the content described in the embodiment of the wind farm wake simulation method, which will not be repeated here.

[0176] Those skilled in the art can understand that all or part of the processes in the method of the above-mentioned embodiment of the present application can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiments when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable files or some intermediate forms, etc. The computer readable storage medium can include any entity or device, medium, U disk, mobile hard disk, magnetic 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. It should be noted that the contents included in the computer readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable storage medium does not include electrical carrier signals and telecommunication signals.

[0177] Further, the present application also provides a control device. In an embodiment of the control device according to the present application, the control device comprises a processor and a storage device, the storage device can be configured to store a program for executing the wake flow simulation method of the wind farm in the above-mentioned method embodiments, and the processor can be configured to execute the program in the storage device, which includes but is not limited to the program for executing the wake flow simulation method of the wind farm in the above-mentioned method embodiments. For the convenience of description, only the parts related to the embodiments of the present application are shown, and the specific technical details not disclosed are referred to the method part of the embodiments of the present application. The control device can be a control device device formed by various electronic devices.

[0178] Further, the present application also provides a computer readable storage medium. In an embodiment of the computer readable storage medium according to the present application, the computer readable storage medium can be configured to store a program for executing the wake flow simulation method of the wind farm in the above-mentioned method embodiments, which can be loaded and run by the processor to implement the above-mentioned wake flow simulation method of the wind farm. For the convenience of description, only the parts related to the embodiments of the present application are shown, and the specific technical details not disclosed are referred to the method part of the embodiments of the present application. The computer readable storage medium can be a storage device device formed by various electronic devices, and optionally, the computer readable storage medium in the embodiments of the present application is a non-transitory computer readable storage medium.

[0179] Further, it should be understood that, since the setting of each module is only for illustrating the functional units of the device of the present application, the corresponding physical device of the module can be the processor itself, or a part of the software in the processor, a part of the hardware, or a part of the combination of the software and the hardware. Therefore, the number of each module in the figure is only illustrative.

[0180] Those skilled in the art can understand that each module in the device can be adaptively split or combined. Such splitting or combining of the specific module does not cause the technical solution to deviate from the principles of the present application, and therefore, the technical solution after splitting or combining will fall within the protection scope of the present application.

[0181] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the present application, and the technical solution after the changes or replacements will fall within the protection scope of the present application.

Claims

1. A method of wake simulation of a wind farm, characterized in that, The method comprises: According to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm, the wind shear factor of the wind farm is obtained; wherein the wind shear factor refers to a parameter reflecting the change of wind direction and wind speed in the control level and / or vertical distance; According to the wind shear factor, the boundary condition of the wind farm is corrected; According to the modified boundary conditions, the wind farm is simulated by using a turbulence model a turbulence model. The step of "obtaining the wind shear factor of the wind farm according to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm" comprises: According to the undisturbed total turbulence intensity at the hub height of the wind farm, the initial fitting roughness of the wind farm is obtained; including obtaining the initial fitting roughness according to the following formula: wherein, is the initial roughness; is the hub height; is the von Karman constant; is the undisturbed total turbulence intensity at the hub height, is a model constant; According to the undisturbed wind speed at the hub height of the wind farm and the initial fitting roughness, the wind shear factor of the wind farm is obtained; including: according to the undisturbed wind speed at the hub height of the wind farm, and according to the following formula, the wind speed at the top of the wind wheel and the wind speed at the bottom of the wind wheel are obtained: wherein, Vtop is the wind speed at the top of the wind wheel; Vbottom is the wind speed at the bottom of the wind wheel; Vundisturbed is the undisturbed wind speed at the hub height; D is the diameter of the wind wheel; According to the wind speed at the top of the wind wheel and the wind speed at the bottom of the wind wheel, and according to the following formula, the wind shear factor is obtained: wherein, is the wind shear factor; The boundary condition includes the fitting roughness and the turbulent kinetic energy of the wind farm, and the step of "correcting the boundary condition of the wind farm according to the wind shear factor" comprises: According to the wind shear factor, the wind shear correction value of the wind farm is obtained; including obtaining the wind shear correction value according to the following formula: wherein, is the wind shear correction value; According to the wind shear correction value, the fitting roughness and the turbulent kinetic energy of the wind farm are corrected, including: According to the wind shear correction value, and according to the following formula, the corrected fitting roughness is obtained; wherein, is the modified fitted roughness; based on the modified fitted roughness and the wind shear correction value, a modified turbulent kinetic energy is obtained according to the following formula: wherein, is the modified turbulent kinetic energy.

2. A wake simulation system for a wind farm, characterized in that The system comprises: A wind shear factor acquisition module configured to obtain the wind shear factor of the wind farm according to the undisturbed wind speed and the undisturbed total turbulence intensity at the hub height of the wind farm; wherein the wind shear factor refers to a parameter reflecting the change of wind direction and wind speed in the control level and / or vertical distance; A wind farm boundary condition correction module configured to correct the boundary condition of the wind farm according to the wind shear factor; a wake simulation module configured to apply a turbulence model to simulate a wake of the wind farm; The wind shear factor acquisition module is further configured to obtain the initial fitting roughness of the wind farm according to the undisturbed total turbulence intensity at the hub height of the wind farm; including obtaining the initial fitting roughness according to the following formula: wherein, is the initial roughness; is the hub height; is the von Karman constant; is the undisturbed total turbulence intensity at hub height, is a model constant; According to the undisturbed wind speed at the hub height of the wind farm and the initial fitting roughness, the wind shear factor of the wind farm is obtained; including: according to the undisturbed wind speed at the hub height of the wind farm, and according to the following formula, the wind speed at the top of the wind wheel and the wind speed at the bottom of the wind wheel are obtained: wherein, Vtop is the wind speed at the top of the wind wheel; Vbottom is the wind speed at the bottom of the wind wheel; Vhub is the undisturbed wind speed at the hub height; D is the diameter of the wind wheel; According to the wind speed at the top of the wind wheel and the wind speed at the bottom of the wind wheel, and according to the following formula, the wind shear factor is obtained: wherein, is the wind shear factor; The boundary condition includes the fitting roughness and the turbulent kinetic energy of the wind farm, and the wind farm boundary condition correction module is further configured to obtain the wind shear correction value of the wind farm according to the wind shear factor; including obtaining the wind shear correction value according to the following formula: wherein, is the wind shear correction value; According to the wind shear correction value, the fitting roughness and the turbulent kinetic energy of the wind farm of the wind farm are corrected; comprising: According to the wind shear correction value, the fitting roughness and the turbulent kinetic energy of the wind farm of the wind farm are corrected; comprising: wherein, is the modified fitted roughness; based on the modified fitted roughness and the wind shear correction value, a modified turbulent kinetic energy is obtained according to the following formula: wherein, is the modified turbulent kinetic energy.

3. A control device comprising a processor and a storage device, the storage device being adapted to store a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to execute the wind farm wake simulation method of claim 1.

4. A computer readable storage medium having stored therein a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to execute the wind farm wake simulation method of claim 1.

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