Wind turbine additional turbulence intensity calculation model construction method suitable for stable atmosphere

Abstract

The invention relates to a wind turbine additional turbulence intensity calculation model construction method suitable for stable atmosphere, and the method comprises the steps: determining a relative wind direction angle of an inflow wind direction at each preset typical height relative to the height of a wind turbine hub based on inflow wind direction angles at a plurality of preset typical heights, and carrying out the fitting to obtain a relation between a vertical height and the relative wind direction angle; therefore, the relative wind direction angle at each vertical height in the vertical height range of the wind wheel in the stable atmospheric state is determined in a simple and rapid mode. According to the method, based on the relative wind direction angle at each vertical height, the transverse offset, caused by different wind directions, of the central point of the additional turbulence intensity profile in each vertical height horizontal plane deviating from the first longitudinal plane at each position of the downwind direction of the wind turbine is determined; an additional turbulence intensity three-dimensional model and a ground effect correction function under the stable atmosphere state are constructed based on the transverse offset, and a wind turbine additional turbulence intensity calculation model suitable for the stable atmosphere is formed based on the additional turbulence intensity three-dimensional model and the ground effect correction function.

Description

Technical Field

[0001] The present invention relates to a method for constructing a wind turbine additional turbulence intensity calculation model suitable for a stable atmosphere, and is suitable for the technical field of wind power generation. Background Art

[0002] In the wake area behind the wind turbine disk, the turbulence intensity is significantly higher than that in the inflow. This increase is called "additional turbulence intensity", which is closely related to the recovery of wind speed loss in the wake area, and thus affects the wind speed at the downwind wind turbine. Therefore, when evaluating the wake effect between units and calculating power generation, it is necessary to consider the "additional turbulence intensity".

[0003] For this reason, the analytical modeling of additional turbulence intensity has received more and more attention in recent years. Among them, the IEC model has been widely used in wind power engineering practice due to its simple form and convenient calculation. However, it ignores the spanwise variation of the additional turbulence intensity profile and deviates greatly from the actual situation. In response to this, the calculation model proposed by Ishihara et al. uses a more realistic bimodal Gaussian function to describe the additional turbulence intensity, and has therefore been recognized by the academic community. However, further in-depth research has found that it ignores the influence of the "wake expansion characteristics", and the treatment of the three-dimensional distribution non-aligned characteristics caused by the ground effect is not perfect, and the calculation accuracy needs to be further improved.

[0004] What's worse, existing model methods represented by the IEC model and the Ishihara model all follow the neutral stratification assumption and do not consider the influence of atmospheric stability. So far, there is still a lack of research results on wind turbine additional turbulence intensity models that can be applied to different atmospheric stabilities. In fact, on a daily time scale, atmospheric stability will show alternating cycles of neutrality, stability, and convection, and long-term series statistics show that the atmospheric stability of a region will deviate from the neutral atmosphere to varying degrees in different trends.

[0005] Studies have shown that compared with a neutral atmosphere, in a stable atmosphere, the turbulence intensity in the inflow is lower, while the vertical shear of the wind direction profile increases significantly. Affected by this, the recovery rate of the additional turbulence intensity in the wake area of ​​the wind turbine slows down. More importantly, its profile shape will tilt significantly following the change in wind direction at different vertical heights, which is significantly different from the characteristics of the approximately symmetrical distribution about the longitudinal plane of the wind wheel in a neutral atmosphere. Due to this, if the existing model method is still used to calculate the additional turbulence intensity of wind turbines in a stable atmosphere, it will lead to a large calculation deviation. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in view of the above-mentioned existing problems, a method for constructing a calculation model of additional turbulence intensity of a wind turbine suitable for a stable atmosphere is provided.

[0007] The technical solution adopted by the present invention is: a method for constructing a calculation model of additional turbulence intensity of a wind turbine applicable to a stable atmosphere, the method being applicable to a stable atmospheric state, comprising: A double-peaked Gaussian function is used to describe the additional turbulence intensity profile in the horizontal plane at the hub height of the wind turbine, and the distance between the peak point of the profile and the center point of the profile is gradually increased as it moves away from the rotor disk surface, forming a two-dimensional model of additional turbulence intensity. Obtaining inflow wind direction angles at a plurality of preset typical heights within the first height range, and calculating the relative wind direction angle of the inflow wind direction angle at each preset typical height relative to the inflow wind direction angle at the height of the wind turbine hub; Fitting the relative wind direction angle at each preset typical height to obtain the relationship between the vertical height and the relative wind direction angle; Based on the relationship between the vertical height and the relative wind direction angle, the relative wind direction angle at each vertical height within the vertical height range of the wind rotor is determined; Based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor, determine the lateral offset of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine, where the lateral offset at the height of the wind turbine hub is 0; Combined with the lateral displacement of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, the additional turbulence intensity two-dimensional model is expanded into an additional turbulence intensity three-dimensional model. Combined with the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, a ground effect correction function is constructed, and the additional turbulence intensity three-dimensional model is corrected using the correction function to form a calculation model for the additional turbulence intensity of the wind turbine. The first height range includes the vertical height range of the wind rotor; the multiple preset typical heights include the wind turbine hub height; the first longitudinal plane is a longitudinal plane passing through the center point of the wind rotor and parallel to the inflow wind direction at the wind turbine hub height.

[0008] The double-peaked Gaussian function is used to describe the additional turbulence intensity profile in the horizontal plane at the wind turbine hub height, including: , In the formula, Downwind direction of wind turbine rotor and the distance from the center point of the additional turbulence intensity profile is Additional turbulence intensity at the location; Downwind direction of wind turbine rotor The additional turbulence intensity peak at ; It is used to describe the wind direction downwind from the wind turbine rotor. The double-peaked Gaussian function of the additional turbulence intensity at , is its standard deviation; , , , In the formula, and are the rotor diameter and thrust coefficient of the wind turbine respectively; is the turbulence intensity at the wind turbine; , when hour: , When hour: , In the formula, and is the weight coefficient; Refers to the distance between the peak point of the additional turbulence intensity profile and its center point.

[0009] The step of gradually increasing the distance between the peak point of the profile and the center point of the profile as the distance from the wind wheel disk surface increases, comprises: Based on the analysis of the high-precision CFD simulation results of the additional turbulence intensity, in the near wake area close to the wind rotor disk, affected by the blade tip vortex, the peak point of the additional turbulence intensity profile does appear approximately at the blade tip, that is, As the wake propagates downstream, the peak point of the profile will gradually move away from the center point due to its continuous momentum exchange with the ambient flow field. The distance between the two can be expressed as Estimate; Since the distribution of additional turbulence intensity in the near wake region is actually very complex and cannot be simply described by a double-peaked Gaussian function, Applied to the near wake region, the This is contrary to the above CFD simulation results; In order to take into account the calculation accuracy of both the far and near wake regions, the following formula is used to estimate : , , In the formula, Refers to the distance between the peak point of the additional turbulence intensity profile and its center point; Downwind direction of the wind wheel The standard deviation of the additional turbulence intensity at ; and are the rotor diameter and thrust coefficient of the wind turbine respectively; is the turbulence intensity at the wind turbine.

[0010] The method of determining the lateral displacement of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor comprises: According to the basic kinematic formula, the lateral offset can be estimated by the following formula: : , In the formula, Represents the inflow wind at the vertical height The lateral velocity at Refers to the propagation of the wind turbine wake to the rear of the rotor The time required is calculated as follows: , In the formula, Represents the inflow wind at the vertical height Flow velocity at From the above, we can get: , In the formula, Vertical height z , The distance from the wind turbine downwind to the wind wheel surface x The distance that the center point of the additional turbulence intensity profile deviates from the first longitudinal plane; is the vertical height of the wind turbine z The relative wind direction angle of the inflow wind direction angle at hub height.

[0011] The additional turbulence intensity two-dimensional model is expanded into an additional turbulence intensity three-dimensional model by combining the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, including: , In the formula, The distance from the wind turbine downwind to the wind rotor surface x The lateral offset between the coordinate point (x, y, z) at any position in the wake section and the central axis of the wind wheel Corrected distance; Vertical height z , The distance from the wind turbine downwind to the wind wheel surface x The distance that the center point of the additional turbulence intensity profile deviates from the first longitudinal plane; is the wind turbine hub height.

[0012] The ground effect correction function is constructed by combining the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, including: , , , In the formula, Downwind direction of wind turbine rotor and the distance from the center point of the additional turbulence intensity profile is Additional turbulence intensity correction value for the location; Downwind direction of wind turbine rotor The additional turbulence intensity peak at ; The distance from the wind turbine downwind to the wind rotor surface x The lateral offset between the coordinate point (x, y, z) at any position in the wake section and the central axis of the wind wheel Corrected distance; Refers to the distance between the peak point of the additional turbulence intensity profile and its center point; is the direction angle; is the wind turbine hub height; Vertical height z , The distance from the wind turbine downwind to the wind wheel surface x The distance that the center point of the additional turbulence intensity profile deviates from the first longitudinal plane.

[0013] A device for constructing a wind turbine additional turbulence intensity calculation model suitable for a stable atmosphere, the device being suitable for a stable atmospheric state, comprising: A two-dimensional model building module is used to describe the additional turbulence intensity profile in the horizontal plane at the hub height of the wind turbine using a bimodal Gaussian function, and gradually increase the distance between the peak point of the profile and the center point of the profile as it moves away from the wind rotor disk surface, thereby forming a two-dimensional model of additional turbulence intensity; A relative angle calculation module, used to obtain the inflow wind direction angles at multiple preset typical heights within the first height range, and calculate the relative wind direction angles of the inflow wind direction angles at each preset typical height relative to the inflow wind direction angle at the wind turbine hub height; A data fitting module is used to fit the relative wind direction angle at each preset typical height to obtain the relationship between the vertical height and the relative wind direction angle; A wind direction angle determination module, used to determine the relative wind direction angle at each vertical height within the vertical height range of the wind rotor based on the relationship between the vertical height and the relative wind direction angle; An offset calculation module is used to determine the lateral offset of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor, wherein the lateral offset at the height of the wind turbine hub is 0; A two-dimensional model expansion module is used to expand the two-dimensional model of additional turbulence intensity into a three-dimensional model of additional turbulence intensity by combining the lateral offset of the center point of the additional turbulence intensity profile at each vertical height level at each location downwind of the wind turbine; The ground effect correction module is used to construct a ground effect correction function by combining the lateral offset of the center point of the additional turbulence intensity profile at each vertical height level at each location downwind of the wind turbine, and use the correction function to correct the additional turbulence intensity three-dimensional model to form a wind turbine additional turbulence intensity calculation model; The first height range includes the vertical height range of the wind rotor; the multiple preset typical heights include the wind turbine hub height; the first longitudinal plane is a longitudinal plane passing through the center point of the wind rotor and parallel to the inflow wind direction at the wind turbine hub height.

[0014] A method for calculating the additional turbulence intensity of a wind turbine applicable to a stable atmosphere, the method being applicable to a stable atmosphere state, comprising: Obtain wind turbine parameters and basic inflow wind data, as well as coordinate information of the points to be calculated, wherein wind turbine parameters include wind turbine hub height, wind rotor diameter, and thrust coefficient; basic inflow wind data include wind direction and turbulence intensity at multiple preset typical heights including wind turbine hub height; Based on wind turbine parameters and inflow wind basic data, an additional turbulence intensity calculation model is constructed using the construction method; The coordinate information of the point to be calculated is input into the additional turbulence intensity calculation model to calculate the additional turbulence intensity of the point to be calculated.

[0015] A storage medium stores a computer program executable by a processor, wherein the computer program, when executed, implements the steps of the method for constructing a wind turbine additional turbulence intensity calculation model.

[0016] A device for constructing a wind turbine additional turbulence intensity calculation model comprises a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed, the steps of the wind turbine additional turbulence intensity calculation model construction method are implemented.

[0017] A storage medium stores a computer program executable by a processor, wherein the computer program implements the steps of the method for calculating the additional turbulence intensity of a wind turbine when executed.

[0018] A wind turbine additional turbulence intensity calculation device comprises a memory and a processor. The memory stores a computer program executable by the processor. When the computer program is executed, the steps of the wind turbine additional turbulence intensity calculation method are implemented.

[0019] The beneficial effects of the present invention are: The present invention determines the relative wind direction angle of the inflow wind direction at each preset typical height relative to the height of the wind turbine hub based on the inflow wind direction angles at multiple preset typical heights, and then fits the relationship between the vertical height and the relative wind direction angle, thereby determining the relative wind direction angle at each vertical height within the vertical height range of the wind rotor under stable atmospheric conditions in a simple and fast manner.

[0020] The present invention determines the lateral displacement of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine caused by different wind directions based on the relative wind direction angle at each vertical height, and then constructs a three-dimensional model of additional turbulence intensity and a ground effect correction function under a stable atmosphere based on the lateral displacement, and forms a calculation model for additional turbulence intensity of a wind turbine suitable for a stable atmosphere based on the three-dimensional model of additional turbulence intensity and the ground effect correction function.

[0021] In the present invention, the parameter r is corrected by the lateral offset, so that the additional turbulence intensity model under the neutral atmospheric state is applicable to the stable atmospheric state.

[0022] The present invention combines the lateral offset of the center point of the additional turbulence intensity profile to construct a ground effect correction function, thereby focusing on the influence of ground effect and vertical wind shear on the additional turbulence intensity in the area below the wind turbine hub height through the ground effect correction function.

[0023] The present invention comprehensively considers the influence of multiple key inflow characteristic quantities such as turbulence intensity and vertical wind shear that follow the changes in atmospheric stability, and constructs the relationship between them and the evolution form of additional turbulence intensity of wind turbines, thereby constructing a calculation model for additional turbulence intensity of wind turbines. Compared with the existing models, the calculation accuracy of the additional turbulence intensity calculation model constructed by the present invention is significantly improved, and it can accurately simulate the change of additional turbulence intensity in the far wake area of ​​the wind turbine with downstream distance, and capture the three-dimensional distribution asymmetric characteristics caused by the coupling of ground effect and strong vertical wind shear in the stable atmosphere.

[0024] The present invention gradually increases the distance between the peak point of the profile and the center point of the profile as the distance from the wind wheel disk surface increases, so that the additional turbulence intensity calculation model takes into account the change in the peak point position caused by the wake expansion.

[0025] The present invention adopts The estimated distance between the peak point and the center point of the additional turbulence intensity profile is consistent with the CFD simulation results, while taking into account the calculation accuracy of the far and wake regions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart for constructing an additional turbulence intensity calculation model in the embodiment.

[0027] Figure 2It is a schematic diagram of the derivation process of the analytical model of additional turbulence intensity of wind turbines in a stable atmosphere in the embodiment.

[0028] Figure 3 This is a cloud diagram of additional turbulence intensity at different downstream locations in the wake region of the NREL 5MW wind turbine in Example 1 of the embodiment.

[0029] Figure 4 1 and 2 are additional turbulence intensity profiles at different downstream positions in the wake region of the NREL 5MW wind turbine in Example 1 of the embodiment, where (a) is the profile in the horizontal plane at the hub height, and (b) is the profile in the mid-longitudinal plane passing through the center point of the wind rotor.

[0030] Figure 5 This is a cloud diagram of additional turbulence intensity at different downstream locations in the wake region of the NREL 5MW wind turbine in Example 2 of the embodiment.

[0031] Figure 6 2 are additional turbulence intensity profiles at different downstream positions in the wake region of the NREL 5MW wind turbine in Example 2 of the embodiment, where (a) is the profile in the horizontal plane at the hub height, and (b) is the profile in the mid-longitudinal plane passing through the center point of the wind rotor.

[0032] Figure 7 This is a cloud diagram of the additional turbulence intensity at 6 times the rotor diameter behind the Vestas 2MW wind turbine disk in Example 3 of the embodiment, where (a) is the CFD simulation result and (b) is the model calculation result. DETAILED DESCRIPTION

[0033] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0034] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0035] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0036] Embodiment 1: This embodiment is a method for constructing a calculation model of additional turbulence intensity of a wind turbine applicable to a stable atmosphere, such as Figure 1 As shown, the construction method specifically includes the following steps: S100, using a bimodal Gaussian function to describe the additional turbulence intensity profile in the horizontal plane at the hub height of the wind turbine, and gradually increasing the distance between the peak point of the profile and the center point of the profile as it moves away from the wind rotor disk surface, thereby forming a two-dimensional model of the additional turbulence intensity in the horizontal plane at the hub height.

[0037] In this embodiment, the location of the wind turbine is taken as the coordinate origin, and the wind direction at the hub height is Positive axis, vertical in horizontal plane The axis direction is Axis direction, the vertical line passing through the center point of the wind wheel is Axis direction (vertical upward The right-hand coordinate system is established. In this coordinate system, the coordinates of the center point of the wind wheel disk are (0, 0, ),in is the wind turbine hub height.

[0038] In the actual operation of the wind turbine, in order to improve its own wind energy absorption efficiency, with the help of the yaw control system, the wind rotor disk is always approximately perpendicular to the inflow wind direction at the center point of the wind rotor disk, that is, the central axis of the wind rotor is parallel to the inflow wind direction at the hub height. In this example, the model derivation also follows the actual engineering development of the inflow wind direction at the perpendicular center point of the wind rotor disk.

[0039] In this embodiment, a double-peaked Gaussian function is used to describe the additional turbulence intensity profile in the horizontal plane at the height of the wind turbine hub (see Figure 2 The calculation formula is: (1) In the formula, Based on x and r The additional turbulence intensity calculation formula constructed represents the downwind direction of the wind turbine rotor disk. and the distance from the center point of the additional turbulence intensity profile is Additional turbulence intensity at the location; is the distance of the downwind position of the wind wheel disk relative to the wind wheel disk surface; Downwind direction of wind turbine rotor The additional turbulence intensity peak at ; It is used to describe the wind direction downwind from the wind turbine rotor. The double-peaked Gaussian function of the additional turbulence intensity at , Downwind The standard deviation of the additional turbulence intensity at .

[0040] In formula (1), Refers to the distance from the point (x, y) at x on the wind rotor disk surface in the horizontal plane at the hub height of the wind turbine, downwind from the wind turbine, relative to the center point of the additional turbulence intensity profile here (the center point of the additional turbulence intensity profile in the horizontal plane at the hub height of the wind turbine is located on the central axis of the wind rotor). As mentioned above, since the direction of the wind rotor disk surface is always approximately perpendicular to the inflow wind direction at the hub height (at the center point of the wind rotor disk surface), in the horizontal plane at the hub height, the center point of the additional turbulence intensity profile at different downstream distances behind the wind rotor disk surface is along the central axis of the wind rotor, so in the horizontal plane at the hub height The calculation formula is: (2) According to the data fitting results of Ishihara et al., the and Calculated by the following formula: (3) (4) (5) In the formula, and are the rotor diameter and thrust coefficient of the wind turbine respectively; is the turbulence intensity at the wind turbine.

[0041] In a wind farm, for upwind wind turbines that are not affected by the wake interference of other wind turbines, The value of can refer to the turbulence intensity in the inflow, such as the turbulence intensity at the hub height, or the average turbulence intensity within the rotor disk surface; for downwind wind turbines, in addition to the turbulence intensity in the inflow, The value of needs to further consider the impact of additional turbulence intensity caused by the operation of upwind wind turbines.

[0042] In formula (1), The calculation formula is: (6) In the formula, and is the weight coefficient; is the distance between the peak point of the additional turbulence intensity profile and its center point.

[0043] In order to keep the calculation results at the peak point of the additional turbulence intensity profile continuous, in this embodiment and The calculation formula is as follows: when hour: (7) When hour: (8) In the Ishihara model, it is assumed that is 0.5 times the wind wheel diameter, expressed as In fact, based on the analysis of the high-precision CFD simulation results of the additional turbulence intensity, in the near wake area close to the wind rotor disk, affected by the blade tip vortex, the peak point of the additional turbulence intensity profile does appear approximately at the blade tip, that is, As the wake propagates downstream, the peak point of the profile will gradually move away from the center point due to its continuous momentum exchange with the ambient flow field. This is called the "wake expansion characteristic". The distance between the peak point of the additional turbulence intensity profile and its center point can be expressed as Estimate.

[0044] Since the distribution of additional turbulence intensity in the near wake region is actually very complex and cannot be simply described by a double-peaked Gaussian function, Applied to the near wake region, the This is contrary to the above CFD simulation results. In view of this, in order to take into account the calculation accuracy of both the far and near wake regions, in this embodiment, the following formula is used to estimate : (9) S200, obtaining inflow wind direction angles at multiple preset typical heights within a first height range (including a vertical height range of a wind rotor), and calculating the relative wind direction angle of the inflow wind direction angle at each preset typical height relative to the inflow wind direction angle at a height of a wind turbine hub.

[0045] In this embodiment, the plurality of preset typical heights at least includes the wind turbine hub height , the vertical height of the tip of the wind wheel disk The vertical height of the tip of the wind wheel disk ; , , In this example, the relative wind direction angle is calculated as follows: , In the formula, is the relative wind direction angle at vertical height z; is the inflow wind direction angle at vertical height z; is the wind turbine hub height The inflow wind direction angle at .

[0046] S300 , based on the calculation result of step S200 , fitting the relative wind direction angle at each preset typical height to obtain the relationship between the vertical height and the relative wind direction angle.

[0047] A number of measured and CFD simulation data show that the inflow wind direction changes approximately linearly with the increase of vertical height under stable atmospheric conditions. Therefore, in this embodiment, a linear fitting method is used to process the relative wind direction angles at multiple preset typical heights obtained in step S200 to obtain a linear relationship between vertical height and relative wind direction angle. In this example, it is necessary to ensure that the linear fitting result is at the height of the wind turbine hub. The relative wind direction angle at is 0.

[0048] S400, based on the relationship between the vertical height and the relative wind direction angle obtained in step S300, determine the relative wind direction angle at each vertical height within the vertical height range of the wind rotor.

[0049] S500, based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor determined in step S400, determine the lateral offset of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine.

[0050] Affected by the strong vertical wind shear in the stable atmospheric inflow, the additional turbulence intensity profile of the wind turbine is not approximately symmetrical with respect to the vertical axis (i.e., z-axis) passing through the center of the wind rotor as in the neutral atmosphere, but will be significantly tilted, as shown in Figure 2 From the perspective of mathematical modeling, this actually corresponds to the deviation of the center point of the additional turbulence intensity profile at different vertical heights in the horizontal plane below the wind rotor disk. xoz plane (a longitudinal plane passing through the center of the wind rotor and parallel to the inflow wind direction at the height of the wind turbine hub, named the first longitudinal plane), Figure 2 In part (b) of express.

[0051] In wind power engineering practice, the center point of the wind wheel disk is always approximately perpendicular to the inflow wind direction at the hub height, which means that in the horizontal plane at the hub height, there are: (10) At other vertical heights Due to the wind direction Relative to wheel hub height Wind direction angle Relative wind direction angle It is an important external driving factor that causes the profile to tilt, so Relative wind direction angle The functional relationship is the focus of modeling.

[0052] According to the basic kinematics formula, it can be estimated by the following formula : (11) In the formula, Represents the inflow wind at the vertical height The transverse (y-axis) velocity at Refers to the propagation of the wind turbine wake to the downwind direction of the wind rotor disk The time required is calculated as follows: (12) In the formula, Represents the inflow wind at the vertical height The flow direction ( x Axial, that is corresponding direction) speed.

[0053] Combining equation (11) and equation (12), we can get: (13) S600, the additional turbulence intensity two-dimensional model is expanded into an additional turbulence intensity three-dimensional model in combination with the lateral displacement of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine.

[0054] Formula (1) is a two-dimensional model of additional turbulence intensity. In this example, r in Formula (1) is adjusted by the following formula to expand the two-dimensional model of additional turbulence intensity into a three-dimensional model of additional turbulence intensity; (14) Affected by the strong vertical wind shear in the stable atmospheric inflow, the additional turbulence intensity profile of the wind turbine will be significantly tilted. Therefore, this application corrects r by the lateral offset. After correction, It can be calculated by the following formula: (15) In formula (15), The lateral offset between the coordinate point (x, y, z) at any position in the wake cross section at a distance x from the rotor disk surface downwind of the wind turbine and the central axis of the rotor Corrected distance.

[0055] In the horizontal plane of the wheel hub height, there are , and according to formula (10), we can know , substituting these two into formula (15), , which is the same as formula (2).

[0056] The vertical shear of wind direction in a neutral atmosphere is very small, that is, the vertical height of the wind is Wind direction angle and hub height at are approximately the same. In this case, they are , , substituting the two into formula (15) we can get , which is the same as the model calculation formula under neutral atmosphere derived by Ishihara et al.

[0057] S700, construct a ground effect correction function based on the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, and use the correction function to correct the additional turbulence intensity three-dimensional model to form a wind turbine additional turbulence intensity calculation model.

[0058] Affected by the ground effect, the additional turbulence intensity in the area below the wind turbine hub height is significantly reduced, and in a stable atmosphere, it will deviate from the inflow wind direction at different vertical heights z to different degrees. xoz flat.

[0059] In view of the above three-dimensional distribution characteristics, the ground effect correction function is given in this embodiment: , based on formula (1), the additional turbulence intensity calculation formula considering the three-dimensional correction is: (16) In this embodiment, the correction function Features are as follows: (1) Above the wind turbine hub height, the function value is fixed to 0; (2) Below the wind turbine hub height, the function peak is , while considering the influence of the "wake expansion characteristics", assuming that the radial distance between the peak point and the central axis of the wind wheel is For the area between the peak point and the central axis of the wind wheel, as the radial distance decreases, the function gradually transitions to 0 in the form of the sine value of the azimuth angle, while in the outer area of ​​the peak point, it is considered that its radial variation still satisfies the Gaussian distribution.

[0060] In this example, the ground effect correction function The specific calculation formula is: (17) Referring to the description of feature (2), the parameters in formula (17) The calculation formula is: (18) In formula (17), is the azimuth, along The positive axis value is 0. The negative axis value is , further considering the influence of strong vertical wind shear on the evolution of additional turbulence intensity in a stable atmosphere, it can be calculated by the following formula: : (19) In this embodiment, the lateral offset of the center point of the additional turbulence intensity profile is based on Determine the azimuth , based on the azimuth Determine the ground effect correction function , thereby focusing on the impact of ground effect and vertical wind shear on the additional turbulence intensity.

[0061] In step S700 of this embodiment, The lateral offset between the coordinate point (x, y, z) at any position in the wake cross section at a distance x from the rotor disk surface downwind of the wind turbine and the central axis of the rotor The corrected distance is calculated using formula (15) to correct for the deviation of the ground effect caused by different inflow wind directions at different vertical heights.

[0062] Embodiment 2: This embodiment is a device for constructing a wind turbine additional turbulence intensity calculation model suitable for a stable atmosphere. The device is suitable for a stable atmospheric state and includes: a two-dimensional model construction module, a relative angle calculation module, a data fitting module, a wind direction angle determination module, an offset calculation module, a two-dimensional model expansion module and a ground effect correction module, etc.

[0063] In this example, the two-dimensional model building module is used to describe the additional turbulence intensity profile in the horizontal plane at the wind turbine hub height using a bimodal Gaussian function, and gradually increase the distance between the profile peak point and the profile center point as it moves away from the wind rotor disk surface, thereby forming a two-dimensional model of additional turbulence intensity.

[0064] In this embodiment, the relative angle calculation module is used to obtain the inflow wind direction angles at multiple preset typical heights within the first height range, and calculate the relative wind direction angle of the inflow wind direction angle at each preset typical height relative to the inflow wind direction angle at the wind turbine hub height.

[0065] The data fitting module is used to fit the relative wind direction angle at each preset typical height to obtain the relationship between the vertical height and the relative wind direction angle.

[0066] In this example, the wind direction angle determination module is used to determine the relative wind direction angle at each vertical height within the vertical height range of the wind rotor based on the relationship between the vertical height and the relative wind direction angle.

[0067] The offset calculation module is used to determine the lateral offset of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor, where the lateral offset at the height of the wind turbine hub is 0.

[0068] In this embodiment, the two-dimensional model expansion module is used to expand the additional turbulence intensity two-dimensional model into an additional turbulence intensity three-dimensional model by combining the lateral offset of the center point of the additional turbulence intensity profile in each vertical height level plane at each location downwind of the wind turbine.

[0069] In this example, the ground effect correction module is used to construct a ground effect correction function by combining the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, and use the correction function to correct the additional turbulence intensity three-dimensional model to form a wind turbine additional turbulence intensity calculation model.

[0070] In this embodiment, the first height range includes the vertical height range of the wind rotor, the multiple preset typical heights include the wind turbine hub height, and the first longitudinal plane is a longitudinal plane passing through the center point of the wind rotor and parallel to the inflow wind direction at the wind turbine hub height.

[0071] Embodiment 3: This embodiment is a storage medium on which a computer program executable by a processor is stored. When the computer program is executed, the steps of the method for constructing a wind turbine additional turbulence intensity calculation model in Embodiment 1 are implemented.

[0072] Embodiment 4: This embodiment is a device for constructing a calculation model of additional turbulence intensity for a wind turbine, comprising a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed, the steps of the method for constructing a calculation model of additional turbulence intensity for a wind turbine in Embodiment 1 are implemented.

[0073] Embodiment 5: This embodiment is a method for calculating the additional turbulence intensity of a wind turbine applicable to a stable atmosphere, which specifically includes the following steps: Step I: Obtain wind turbine parameters and basic inflow wind data, as well as the location to be calculated. xyz Three-axis coordinate information, where wind turbine parameters mainly include wind turbine hub height , Wind wheel diameter and thrust coefficient ; Basic inflow wind data includes wind direction angles at multiple preset typical heights including the wind turbine hub height and turbulence intensity I .

[0074] Step II: Based on the wind turbine parameters and the basic data of the inflow wind, an additional turbulence intensity calculation model is constructed using the method for constructing an additional turbulence intensity calculation model for a wind turbine in a stable atmosphere in Example 1.

[0075] Step III: input the coordinate information of the point to be calculated into the additional turbulence intensity calculation model to calculate the additional turbulence intensity of the point to be calculated.

[0076] The effectiveness and reliability of this embodiment are illustrated by three specific examples below: Both Example 1 and Example 2 use the NREL 5MW wind turbine as the research object, with a rotor diameter and hub height of 126 m and 90 m respectively. In both examples, the wind turbines are operated in a stable atmosphere, with a turbulence intensity of about 0.046 at the hub height, and a wind direction angle difference of about 8.6° between the upper and lower ends of the rotor disk. The difference between the two examples is that the wind turbine in Example 1 maintains the optimal tip speed ratio, and the corresponding thrust coefficient is about 0.72, while in Example 2, the tip speed ratio is fixed at 5.77 by adjusting the wind turbine speed, and the corresponding thrust coefficient is about 0.57.

[0077] Using high-precision CFD simulation results as a reference benchmark, Figure 3 and Figure 5 The cloud diagrams of the additional turbulence intensity at 4, 6, and 8 times the rotor diameter behind the wind turbine disk in the above two examples are given in turn. In order to more clearly quantify the accuracy differences of different model methods, two representative sections, the horizontal plane at the height of the wind turbine hub and the mid-longitudinal plane passing through the center of the wind rotor, are selected. Figure 4 and Figure 6 The calculation results of the additional turbulence intensity profile are compared in .

[0078] Figure 3-Figure 5 In the legend, CFD, New, Ishihara and IEC respectively represent the CFD simulation results, the calculation model for the additional turbulence intensity of wind turbines proposed in this embodiment, and the calculation results of the Ishihara model and IEC model commonly used in the current academic and engineering circles. As can be seen from the figure, overall, under the two different wind turbine operating conditions described in Example 1 and Example 2, the calculation model for the additional turbulence intensity of wind turbines proposed in this embodiment can better capture the change of the additional turbulence intensity of wind turbines with downstream distance under stable atmosphere, accurately simulate the asymmetric profile morphology caused by the strong vertical shear of wind direction in the inflow, which is in good agreement with the CFD simulation results, and the calculation accuracy is significantly improved compared with the other two existing model methods.

[0079] In order to test the robustness of the new model of the present invention, Example 3 uses the Vestas 2MW wind turbine as the research object, whose rotor diameter and hub height are 80 m and 70 m respectively. The CFD simulation results are still used as the reference benchmark. The inflow turbulence intensity at the hub height is about 0.05, and the wind direction angle difference between the upper and lower ends of the blade is about 10°.

[0080] Under the above wind conditions, Figure 7The turbulence intensity cloud map at 6 times the diameter of the wind rotor behind the wind turbine disk is displayed. By comparison, it can be seen that the deviation between the IEC model and the CFD simulation results is the largest. In comparison, the calculation results of the wind turbine additional turbulence intensity calculation model proposed in this embodiment are most consistent with the CFD cloud map. Because the Ishihara model only simply deals with the ground effect, it cannot accurately describe the additional turbulence intensity in the area below the height of the wind turbine hub. It even has erroneous correction increments near the ground and about 1 times the rotor diameter away from the central axis of the wind rotor. More importantly, because the influence of vertical shear of wind direction is ignored, the turbulence intensity calculated by it is approximately symmetrically distributed about the central axis of the wind rotor, which seriously deviates from the CFD simulation results.

[0081] Embodiment 6: This embodiment is a storage medium on which a computer program executable by a processor is stored. When the computer program is executed, the steps of the method for calculating the additional turbulence intensity of a wind turbine in Embodiment 5 are implemented.

[0082] Embodiment 7: This embodiment is a device for calculating the additional turbulence intensity of a wind turbine, comprising a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed, the steps of the method for calculating the additional turbulence intensity of a wind turbine in Embodiment 5 are implemented.

Claims

1. A method for constructing a calculation model for additional turbulence intensity of a wind turbine suitable for a stable atmosphere, characterized in that: The method is applicable to stable atmospheric conditions, including: A double-peaked Gaussian function is used to describe the additional turbulence intensity profile in the horizontal plane at the hub height of the wind turbine, and the distance between the peak point of the profile and the center point of the profile is gradually increased as it moves away from the rotor disk surface, forming a two-dimensional model of additional turbulence intensity. Obtaining inflow wind direction angles at a plurality of preset typical heights within the first height range, and calculating the relative wind direction angle of the inflow wind direction angle at each preset typical height relative to the inflow wind direction angle at the height of the wind turbine hub; Fitting the relative wind direction angle at each preset typical height to obtain the relationship between the vertical height and the relative wind direction angle; Based on the relationship between the vertical height and the relative wind direction angle, the relative wind direction angle at each vertical height within the vertical height range of the wind rotor is determined; Based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor, determine the lateral offset of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine, where the lateral offset at the height of the wind turbine hub is 0; Combined with the lateral displacement of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, the additional turbulence intensity two-dimensional model is expanded into an additional turbulence intensity three-dimensional model. Combined with the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, a ground effect correction function is constructed, and the additional turbulence intensity three-dimensional model is corrected using the correction function to form a calculation model for the additional turbulence intensity of the wind turbine. The first height range includes the vertical height range of the wind rotor; the multiple preset typical heights include the wind turbine hub height; the first longitudinal plane is a longitudinal plane passing through the center point of the wind rotor and parallel to the inflow wind direction at the wind turbine hub height.

2. The method for constructing a wind turbine additional turbulence intensity calculation model applicable to a stable atmosphere according to claim 1, characterized in that: The double-peaked Gaussian function is used to describe the additional turbulence intensity profile in the horizontal plane at the wind turbine hub height, including: , where Downwind direction of wind turbine rotor and the distance from the center point of the additional turbulence intensity profile is Additional turbulence intensity at the location; Downwind direction of wind turbine rotor The additional turbulence intensity peak at ; It is used to describe the wind direction downwind from the wind turbine rotor. The double-peaked Gaussian function of the additional turbulence intensity at , is its standard deviation; ， ， ， In the formula, and are the rotor diameter and thrust coefficient of the wind turbine respectively; is the turbulence intensity at the wind turbine; ， when hour: ， When hour: , where and is the weight coefficient; Refers to the distance between the peak point of the additional turbulence intensity profile and its center point.

3. The method for constructing a wind turbine additional turbulence intensity calculation model applicable to a stable atmosphere according to claim 1, characterized in that: The step of gradually increasing the distance between the peak point of the profile and the center point of the profile as the distance from the wind wheel disk surface increases, comprises: Based on the analysis of the high-precision CFD simulation results of the additional turbulence intensity, in the near wake area close to the wind rotor disk, affected by the blade tip vortex, the peak point of the additional turbulence intensity profile does appear approximately at the blade tip, that is, As the wake propagates downstream, the peak point of the profile will gradually move away from the center point due to its continuous momentum exchange with the ambient flow field. The distance between the two can be expressed as Estimate; Since the distribution of additional turbulence intensity in the near wake region is actually very complex and cannot be simply described by a double-peaked Gaussian function, Applied to the near wake region, the This is contrary to the above CFD simulation results; In order to take into account the calculation accuracy of both the far and near wake regions, the following formula is used to estimate : ， ， In the formula, Refers to the distance between the peak point of the additional turbulence intensity profile and its center point; Downwind direction of the wind wheel The standard deviation of the additional turbulence intensity at ; and are the rotor diameter and thrust coefficient of the wind turbine respectively; is the turbulence intensity at the wind turbine.

4. The method for constructing a wind turbine additional turbulence intensity calculation model applicable to a stable atmosphere according to claim 1, characterized in that: The method of determining the lateral displacement of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor comprises: According to the basic kinematic formula, the lateral offset can be estimated by the following formula: : ， In the formula, Represents the inflow wind at the vertical height The lateral velocity at Refers to the propagation of the wind turbine wake to the rear of the rotor The time required is calculated as follows: ， In the formula, Represents the inflow wind at the vertical height Flow velocity at From the above, we can get: ， In the formula, Vertical height z , The distance from the wind turbine downwind to the wind wheel surface x The distance that the center point of the additional turbulence intensity profile deviates from the first longitudinal plane; is the vertical height of the wind turbine z The relative wind direction angle of the inflow wind direction angle at hub height.

5. The method for constructing a wind turbine additional turbulence intensity calculation model applicable to a stable atmosphere according to claim 2, characterized in that: The additional turbulence intensity two-dimensional model is expanded into an additional turbulence intensity three-dimensional model by combining the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, including: ， In the formula, The distance from the wind turbine downwind to the wind rotor surface x The lateral offset between the coordinate point (x, y, z) at any position in the wake section and the central axis of the wind wheel Corrected distance; Vertical height z , The distance from the wind turbine downwind to the wind wheel surface x The distance that the center point of the additional turbulence intensity profile deviates from the first longitudinal plane; is the wind turbine hub height.

6. The method for constructing a wind turbine additional turbulence intensity calculation model applicable to a stable atmosphere according to claim 1, characterized in that: The ground effect correction function is constructed by combining the lateral offset of the center point of the additional turbulence intensity profile in each vertical height horizontal plane at each location downwind of the wind turbine, including: ， ， ， In the formula, Downwind direction of wind turbine rotor and the distance from the center point of the additional turbulence intensity profile is Additional turbulence intensity correction value for the location; Downwind direction of wind turbine rotor The additional turbulence intensity peak at ; The distance from the wind turbine downwind to the wind rotor surface x The lateral offset between the coordinate point (x, y, z) at any position in the wake section and the central axis of the wind wheel Corrected distance; Refers to the distance between the peak point of the additional turbulence intensity profile and its center point; is the direction angle; is the wind turbine hub height; Vertical height z , The distance from the wind turbine downwind to the wind wheel surface x The distance that the center point of the additional turbulence intensity profile deviates from the first longitudinal plane.

7. A device for constructing a calculation model of additional turbulence intensity of a wind turbine suitable for a stable atmosphere, characterized in that: The device is suitable for stabilizing atmospheric conditions and includes: A two-dimensional model building module is used to describe the additional turbulence intensity profile in the horizontal plane at the hub height of the wind turbine using a bimodal Gaussian function, and gradually increase the distance between the peak point of the profile and the center point of the profile as it moves away from the wind rotor disk surface, thereby forming a two-dimensional model of additional turbulence intensity; A relative angle calculation module, used to obtain the inflow wind direction angles at multiple preset typical heights within the first height range, and calculate the relative wind direction angles of the inflow wind direction angles at each preset typical height relative to the inflow wind direction angle at the wind turbine hub height; A data fitting module is used to fit the relative wind direction angle at each preset typical height to obtain the relationship between the vertical height and the relative wind direction angle; A wind direction angle determination module, used to determine the relative wind direction angle at each vertical height within the vertical height range of the wind rotor based on the relationship between the vertical height and the relative wind direction angle; An offset calculation module is used to determine the lateral offset of the center point of the additional turbulence intensity profile in the horizontal plane at each vertical height from the first longitudinal plane at each location downwind of the wind turbine based on the relative wind direction angle at each vertical height within the vertical height range of the wind rotor, wherein the lateral offset at the height of the wind turbine hub is 0; A two-dimensional model expansion module is used to expand the two-dimensional model of additional turbulence intensity into a three-dimensional model of additional turbulence intensity by combining the lateral offset of the center point of the additional turbulence intensity profile at each vertical height level at each location downwind of the wind turbine; The ground effect correction module is used to construct a ground effect correction function by combining the lateral offset of the center point of the additional turbulence intensity profile at each vertical height level at each location downwind of the wind turbine, and use the correction function to correct the additional turbulence intensity three-dimensional model to form a wind turbine additional turbulence intensity calculation model; The first height range includes the vertical height range of the wind rotor; the multiple preset typical heights include the wind turbine hub height; the first longitudinal plane is a longitudinal plane passing through the center point of the wind rotor and parallel to the inflow wind direction at the wind turbine hub height.

8. A method for calculating the additional turbulence intensity of a wind turbine in a stable atmosphere, characterized in that: The method is applicable to stable atmospheric conditions, including: Obtain wind turbine parameters and basic inflow wind data, as well as coordinate information of the points to be calculated, wherein wind turbine parameters include wind turbine hub height, wind rotor diameter, and thrust coefficient; basic inflow wind data include wind direction and turbulence intensity at multiple preset typical heights including wind turbine hub height; Based on wind turbine parameters and inflow wind basic data, an additional turbulence intensity calculation model is constructed using the construction method described in any one of claims 1 to 6; The coordinate information of the point to be calculated is input into the additional turbulence intensity calculation model to calculate the additional turbulence intensity of the point to be calculated.

9. A storage medium having stored thereon a computer program executable by a processor, characterized in that: When the computer program is executed, the steps of the method for constructing a wind turbine additional turbulence intensity calculation model as described in any one of claims 1 to 6 are implemented.

10. A device for constructing a wind turbine additional turbulence intensity calculation model, comprising a memory and a processor, wherein the memory stores a computer program executable by the processor, characterized in that: When the computer program is executed, the steps of the method for constructing a wind turbine additional turbulence intensity calculation model as described in any one of claims 1 to 6 are implemented.

11. A storage medium having stored thereon a computer program executable by a processor, characterized in that: When the computer program is executed, the steps of the method for calculating the additional turbulence intensity of a wind turbine according to claim 8 are implemented.

12. A wind turbine additional turbulence intensity calculation device, comprising a memory and a processor, wherein the memory stores a computer program executable by the processor, characterized in that: When the computer program is executed, the steps of the method for calculating the additional turbulence intensity of a wind turbine according to claim 8 are implemented.

Images