An active control optimization system and method for fan wake

Abstract

An active control optimization system and method for wind turbine wakes, which reduces the temperature of the wake air and increases its density by spraying atomized water droplets, so as to increase the wind speed and improve the inflow conditions of downstream wind turbines. The facility includes a water source supply device, a high-pressure atomization device and a control unit. The water source supply device is responsible for supplying water to the high-pressure atomization device, and the high-pressure atomization device atomizes the water and sprays it into the wake area, prompting the water droplets to vaporize and absorb heat, thereby achieving air cooling and density increase. The system and method of the present invention not only improve the power generation efficiency of the wind farm, but also extend the service life of the wind turbines, are applicable to offshore and onshore wind farms, and have significant economic benefits.

Description

Technical Field

[0001] The present invention relates to wind farm technology, and particularly to an active control optimization system and method for wind turbine wakes. Background Art

[0002] The wake of a wind turbine is a low-speed and high-turbulence region formed downstream after the operation of the wind turbine, and its influence range can reach more than 15 times the impeller diameter. The existence of the wake will cause a significant loss of power of the wind turbine behind the wake, and at the same time trigger a sharp increase of 80% in the stress fluctuation of the tower barrel, accelerating the fatigue failure of components such as the wind turbine blades. When an inversion layer exists, the low-wind-speed period of the wake will even be extended by 2-3 times, which will lead to a significant reduction in the equivalent full-load hours of the wind farm in this scenario, causing significant economic losses. Therefore, the active control optimization technology of the wake is of great significance for the development of the wind power industry, which can reduce the power loss of the downstream wind turbine while reducing the influence of the high-turbulence region on the fatigue load of the wind turbine components.

[0003] Currently, there are a large number of wake control technical solutions, such as Chinese patent applications with application numbers 2024110678791, 2024105633818, 202310853932X, 2021116713348, 2024105633818, 2024101642625, 2023110095577, 2022112893717, 2022110933086, 2021116713348, etc. These solutions basically change the flow direction of the wake by the yaw angle of the wind turbine, so that the main flow direction of the wake can avoid the next wind turbine as much as possible, thereby reducing power loss. The prior art has continuously studied many yaw optimization strategies to further improve this solution. However, the existing solutions often sacrifice the power generation of the first wind turbine. At the same time, for a wind farm with a relatively dense layout, even if the influence of the wake on the current array of wind turbines is reduced, it may also increase the degree of influence of the wake on the adjacent array of wind turbines. Therefore, the optimization effect is usually limited (5% - 15%). Therefore, if a better control of the wake is to be achieved, a breakthrough wake optimization control solution is urgently needed.

[0004] It should be noted that the information disclosed in the above background art section is only used for understanding the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] The main object of the present invention is to overcome the defects existing in the above background art, and provide an active control optimization system and method for wind turbine wakes.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An active control optimization system for the wake of a wind turbine, comprising:

[0008] A water source supply device for supplying water to the high-pressure atomization device;

[0009] The high-pressure atomization device is arranged at the position of the wind turbine hub nacelle and is connected to the water source supply device, and is used for atomizing water and spraying it into the wake area. Among them, the sprayed atomized water droplets achieve gasification phase change endotherm in the wake area, reduce the temperature of the wake air and increase its density, and the wake air generates a downward component velocity, inducing the high-speed air above the wake area to supplement downward, thereby increasing the wind speed in the wake area and improving the inflow conditions of the downstream wind turbine;

[0010] The control unit is used to control the operation of the water source supply device and the high-pressure atomization device, including controlling the water extraction volume, the spraying parameters of the atomized water droplets and the operating state of wake induction, so as to optimize the wind speed distribution in the wake area and increase the inflow wind speed and power generation efficiency of the downstream wind turbine.

[0011] Furthermore, the wind turbine is an offshore wind turbine, and the water source supply device includes a seawater extraction device for extracting seawater and transporting it to the high-pressure atomization device.

[0012] Furthermore, the seawater extraction device includes a seawater filtration device, a water supply high-pressure pump and a vacuum pump, which are installed around the wind turbine tower barrel on the sea surface. Among them, the seawater filtration device is used for filtering seawater, the water supply high-pressure pump is used for transporting the filtered seawater to the high-pressure atomization device, and the vacuum pump is used for extracting seawater.

[0013] Furthermore, the high-pressure atomization device includes an atomization high-pressure pump and an atomization nozzle assembly. Among them, the atomization high-pressure pump is used for pressurizing and transporting the liquid working medium to the atomization nozzle assembly; the atomization nozzle assembly includes a plurality of atomization nozzles, and the plurality of atomization nozzles are evenly distributed in a preset area behind the nacelle and are connected to the atomization high-pressure pump through a water supply pipeline.

[0014] Furthermore, the rated flow of the atomization high-pressure pump is not less than 1500 liters per minute @ 4 Mpa to meet the spraying process of atomized water droplets with a particle size of 0.1 mm to 0.2 mm and a flow rate of 0 to 25 kg / s.

[0015] Furthermore, the atomization nozzles are distributed in a circular or rectangular range area at least 100 m behind the nacelle and are connected to the atomization high-pressure pump through a water supply pipe, and the flow rate of a single atomization nozzle is 3 to 6 liters per minute. 2 The circular or rectangular range area of not less than 100 m behind the nacelle, and is connected to the atomization high-pressure pump through a water supply pipe, and the flow rate of a single atomization nozzle is 3 to 6 liters per minute.

[0016] Furthermore, the atomization spraying range of the high-pressure atomization device in the area behind the nacelle is not less than 100 m 2; the flow rate range of the water droplets sprayed per second is 0 - 50 Kg / s; the particle size range of the water droplets is between 0.1 mm and 0.2 mm; the air temperature when spraying the water droplets is not lower than 285 K.

[0017] An active control optimization method for the wake of a wind turbine, which uses the active control optimization system for the wake of a wind turbine described above to optimize the active control of the wake of a wind turbine. Among them, by spraying atomized water droplets into the wake area of the wind turbine, the density of the wake air increases after the temperature drops, and a downward component velocity is generated in the wake area. After the wake air sinks, the high-speed air above the wake area is induced into the wake area to supplement the sinking air, thereby increasing the wind speed in the wake area and improving the inflow conditions of the downstream wind turbines.

[0018] The present invention has the following beneficial effects:

[0019] The present invention provides an active control optimization system and method for the wake of a wind turbine. By spraying atomized water droplets to achieve endothermic gasification phase change, it effectively reduces the temperature of the wake air and increases its density, promotes the sinking of the wake air, and induces the high-altitude wind speed into the wake area, thereby significantly increasing the inflow wind speed and power generation efficiency of the rear-row wind turbines. Compared with the prior art, the present invention can not only reduce the power loss of the wake on the downstream wind turbines, but also reduce the impact of the high-turbulence area on the fatigue load of the wind turbine components, improve the service life of the wind turbine and reduce the maintenance cost. In addition, the technical solution of the present invention is not limited to offshore wind farms, but also applicable to onshore wind farms, especially those close to sufficient water sources, and has wide applicability and practicability. Through this breakthrough wake optimization control scheme, the present invention can achieve better wake control effects than the prior art, bringing significant economic benefits to the development of the wind power industry.

[0020] Other beneficial effects in the embodiments of the present invention will be further described below. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the active control optimization system for the wake of a wind turbine according to an embodiment of the present invention.

[0022] Figure 2 It is a schematic structural diagram of the active control optimization system for the wake of a wind turbine from another angle according to an embodiment of the present invention.

[0023] Figure 3a It is a schematic diagram of the mesh division for the numerical simulation of the wind turbine wake.

[0024] Figure 3b It is a schematic diagram of the wind turbine layout.

[0025] Figure 4Schematic diagram of the wake flow field generated when the incoming flow velocity of 8 m / s passes through a 2 MW wind turbine array under neutral stable atmospheric boundary layer conditions. It shows the low-speed and high-turbulence region in the wake area and its impact on downstream wind turbines.

[0026] Figure 5 Schematic diagram of setting a heat absorption source term in the lower half swept area of the wind turbine. It shows the position of the heat absorption source term in the wake area of the wind turbine, used to simulate the cooling effect of the wake air.

[0027] Figure 6a Schematic diagram of the change in the wake flow velocity distribution after setting the heat absorption source term.

[0028] Figure 6b Schematic diagram of the air temperature distribution in the wake.

[0029] Figure 6c Schematic diagram of the air density distribution in the wake area.

[0030] Figure 6d Schematic diagram of the vertical (z-direction) component velocity distribution in the wake area.

[0031] Figure 7 Overall schematic diagram of the seawater spray system according to the embodiment of the present invention.

[0032] Figure 8 Schematic diagram of the wake temperature, density, and component velocity distributions after injecting water droplets using DPM.

[0033] Figure 9 Schematic diagram of the wake turbulent kinetic energy distribution.

[0034] Figure 10 Schematic diagram of the vertical component velocity distribution in the wake considering the buoyancy effect and a relative humidity of 70%.

[0035] Figure 11 Schematic diagram of the power improvement of downstream wind turbines considering the buoyancy effect and a relative humidity of 70%.

[0036] Figure 12 Schematic diagram for simulating the layout of the HornsRev wind farm.

[0037] Figure 13 Diagram of the wind farm power situation before and after adopting the active control optimization system for the wind turbine wake of the present invention at the first wind turbine in the wind farm. Detailed implementation mode

[0038] The following gives a detailed description of the implementation mode of the present invention. It should be emphasized that the following description is merely exemplary and not intended to limit the scope of the present invention and its applications.

[0039] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. Additionally, the connection can be for fixing purposes or for coupling or communicating purposes.

[0040] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0041] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0042] Previous studies have often been limited to the perspective of horizontal adjustment and rarely considered attempting to break through from the higher wind speed area above the wake region. Based on in-depth research on the evolution process of large-scale wind turbine wakes and the liquid phase change process in microscale heat transfer, this application proposes a practical way to guide the upper-layer high wind speed to the wake region, thereby increasing the inflow wind speed of the rear-row wind turbines and reducing the impact caused by the wake.

[0043] Refer to Figure 1 、 Figure 2 and Figure 7, an embodiment of the present invention provides an active control optimization system for a wind turbine wake, including: a water source supply device 2 that supplies water to a high-pressure atomization device 3 through a pumping device (not shown) and a water supply pipeline; the high-pressure atomization device 3 is disposed at the nacelle 1 position of the wind turbine hub and is connected to the water source supply device 2 for atomizing water and spraying it into the wake area. Among them, the sprayed atomized water droplets undergo gasification phase change endothermic in the wake area, reducing the wake air temperature and increasing its density. The wake air generates a downward component velocity, inducing the high-speed air above the wake area to supplement downward, thereby increasing the wind speed in the wake area and improving the inflow conditions of the downstream wind turbines; a control unit (not shown) for controlling the operation of the water source supply device 2 and the high-pressure atomization device 3. The control of the control unit can specifically include controlling the water extraction volume, the spraying parameters of the atomized water droplets, and the operating state of the wake induction to optimize the wind speed distribution in the wake area and increase the inflow wind speed and power generation efficiency of the downstream wind turbines.

[0044] In a preferred embodiment, the wind turbine is an offshore wind turbine, and the water source supply device 2 includes a seawater extraction device for extracting seawater and transporting it to the high-pressure atomization device 3.

[0045] In a preferred embodiment, the seawater extraction device includes a seawater filtration device, a water supply high-pressure pump, and a vacuum pump, which are installed around the wind turbine tower barrel on the sea surface. Among them, the seawater filtration device is used to filter seawater, the water supply high-pressure pump is used to transport the filtered seawater to the high-pressure atomization device 3, and the vacuum pump is used to extract seawater.

[0046] Refer to Figure 1 , in a preferred embodiment, the high-pressure atomization device 3 includes an atomization high-pressure pump (not shown) and an atomization nozzle assembly. Among them, the atomization high-pressure pump is used to pressurize and transport the liquid working medium to the atomization nozzle assembly; the atomization nozzle assembly includes a plurality of atomization nozzles. As Figure 1 shown, the plurality of atomization nozzles are evenly distributed in a preset area behind the nacelle 1 and are connected to the atomization high-pressure pump through a water supply pipeline. The nozzle spacing meets the discrete requirements of the atomized droplets to form a uniform atomization coverage in the wake area. The control unit adjusts the atomization parameters and can dynamically adjust the atomization particle size to a preset range and control the outflow rate of a single nozzle.

[0047] In a preferred embodiment, the rated flow rate of the atomization high-pressure pump is not less than 1500 liters / min@4 Mpa to meet the spraying process of atomized water droplets with a particle size of 0.1 mm to 0.2 mm at 0 to 25 kg / s.

[0048] In a preferred embodiment, the atomization nozzles are distributed in a circular or rectangular range area at least 100 m 2 behind the nacelle 1 and are connected to the atomization high-pressure pump through a water supply pipe. The flow rate of a single atomization nozzle is 3 to 6 liters / min.

[0049] In a preferred embodiment, the atomization spraying range of the high-pressure atomization device 3 in the rear area of the nacelle 1 is not less than 100 m 2 ; the water droplet flow rate per second ranges from 0 to 50 Kg / s; the particle size range of the water droplets is between 0.1 mm and 0.2 mm; the air temperature when spraying the water droplets is not lower than 285 K.

[0050] The embodiment of the present invention further provides a method for optimizing the active control of the wind turbine wake. The active control of the wind turbine wake is optimized by using the active control optimization system of the wind turbine wake in any of the foregoing embodiments. Among them, by spraying atomized water droplets into the wake area of the wind turbine, the density of the wake air increases after cooling due to the endothermic gasification phase change of the atomized water droplets, and a downward component velocity is generated in the wake area. After the wake air sinks, the high-speed air above the wake area is induced to enter the wake area to supplement the sinking air, thereby increasing the wind speed in the wake area and improving the inflow conditions of the downstream wind turbines.

[0051] The specific embodiments and effect verification of the present invention are further described below.

[0052] An active control optimization system for a wind turbine wake provides a solution for spraying atomized water droplets to absorb heat through gasification phase change to cool the air, causing the wake air with a relatively high density in the environment to sink. The system includes a water source supply device 2, a high-pressure atomization device 3, and a control unit. For an offshore wind turbine, the water source supply device 2 pumps seawater from the sea to the position of the nacelle 1 of the wind turbine hub. The seawater is sprayed out through the high-pressure atomization device 3 installed at the position of the nacelle 1. With the help of the temperature difference and high wind speed, the gasification process of the water droplets is accelerated, so that the wake air cools and sinks, and finally the high-altitude wind speed is induced to enter the wake area.

[0053] The water source supply device 2 in one embodiment mainly includes a seawater filtration device, a water supply high-pressure pump, and a vacuum pump. It is installed around the tower barrel on the sea surface, with a rated flow rate of not less than 3000 liters / min@2 Mpa at a suction depth of 3 m. Since seawater is pumped, the material is required to be seawater corrosion-resistant. The vertical water supply height of the water supply high-pressure pump can reach 100 m. The vacuum pump can adopt a mechanical fully automatic piston vacuum pump.

[0054] The high-pressure atomization device 3 includes an atomization high-pressure pump and atomizing nozzles, which are installed at the position of the nacelle 1. On the premise of meeting the tower barrel load-bearing capacity, the system can be installed outside the nacelle 1. The rated flow of the atomization high-pressure pump is not less than 1500 liters per minute @ 4 Mpa to meet the spraying process of atomized water droplets with a particle size of 0.1 mm to 0.2 mm at 0 to 25 kg / s. The atomizing nozzles are distributed in a circular or rectangular area behind the nacelle 1 and are connected through a water supply pipe. The atomizing nozzles can adopt the Lechler 502.448 model nozzles. These nozzles can provide atomized water droplets with a particle size of about 0.1 to 0.2 mm according to different operating pressures of 1 Mpa to 4 Mpa. The flow rate of a single nozzle is 3 to 6 liters per minute, and there are a total of 250 nozzles. To ensure the evaporation effect of the water droplets after atomization and reduce the agglomeration effect between the atomized water droplets, a certain distance needs to be ensured between each nozzle. Therefore, the nozzles are evenly distributed in a circular or rectangular space area of at least 100 m behind the nacelle 1 and are connected by a water delivery pipe. The maximum power of the high-pressure atomization device 3 is the maximum pressure multiplied by the maximum flow rate, that is, the atomized water spraying at 25 kg / s under 4 Mpa, and the power is 100 KW. In fact, the purpose of reducing power consumption can be achieved by increasing the number of nozzles and reducing the atomization particle size. 2 The control unit controls the operation of the water source supply device 2 and the high-pressure atomization device 3, including controlling the extraction volume of seawater (land fresh water), the spraying parameters of atomized water droplets, and the operating state of the wake induction device. It can be adjusted in real time according to the severity of the wake influence on the actual wind farm. Similar to the wake optimization control system adopting the yaw scheme, a similar algorithm can also be designed.

[0055] Based on the FLUENT software, the wake of the wind turbine is numerically simulated. The mesh division and the wind turbine layout are as

[0056] and Figure 3a shown. Figure 3b shows the schematic diagram of the mesh division for the numerical simulation of the wind turbine wake. Different boundary conditions are marked in the figure, including the pressure outlet a1, the zero-shear upper boundary a2, the velocity inlet a3, the no-slip bottom boundary a4, and the periodic boundary a5. The sizes of the meshes are 250 m, 500 m, and 2000 m respectively, which are used to simulate different regions of the wind farm. Figure 3a shows the schematic diagram of the wind turbine layout. The figure shows the incoming flow wind speed b1, the wake region b2, the upper tip height b3, the hub height b4, and the lower tip height b5. The distribution of the wind turbine wake region is shown through the coordinate axes (x / d and z / d), where x / d represents the horizontal distance and z / d represents the vertical height. Under the condition of a neutrally stable atmospheric boundary layer, the incoming flow wind speed of 8 m / s will generate a wake field as Figure 3b shown when passing through a 2 MW wind turbine array. Assume that a fixed heat absorption source term is provided at the wind turbine position, such as in the lower half-swept region of the wind turbine as Figure 4 shown.Figure 5 As shown. After setting the heat absorption source term, when the wind field passes through this area, heat will be absorbed, resulting in a cooling effect. When the calculation reaches a steady state, it is found that the wind speed distribution in the wake has changed significantly. For example, Figure 6a as shown, it is found that the low wind speed distribution in the wake no longer distributes flatly along the downstream direction, but shows a certain degree of downward trend. At the same time, compared with the result without adding the heat absorption source term, the wind speed at the inflow position of the second fan below the wake has increased significantly. The fundamental reason for this phenomenon is that the air temperature in the wake decreases ( Figure 6b ), which in turn leads to an increase in the density of the local air ( Figure 6c ). Since its density is lower than that of the lower-layer air, a downward component velocity is generated in the wake area. As Figure 6d shown, the maximum component velocity in the z direction reaches -1 m / s, which induces the air above the wake to supplement downward, and finally accelerates the recovery process of the wake wind speed. By comparing the power of the second and third fans before and after cooling, it is found that the power of the second fan has increased by about 30% after cooling, and the third fan has increased by about 40%. For the optimal control of the wake, this is an unprecedented improvement.

[0057] By integrating the heat absorption source term in the cooling area behind the first fan, it is found that to achieve the Figure 6b shown cooling effect of the wake air, a total of 5×10 7 Joules of heat need to be absorbed per second behind the wake. This is a very large amount of heat. Even if the power of the second fan has increased by 30%, the specific value of the increased power is only about 1.4×10 6 W, which is significantly smaller than 5×10 7 . The problem at this time is how to use the energy lower than the fan power gain to achieve the effect of reducing the required temperature. The ideal approach is to utilize the existing heat in reality, so the latent heat of phase change of water is considered.

[0058] The atomized water droplets will quickly evaporate and gasify in the high-speed flowing higher-temperature air. This phase change process is sufficient to take away a large amount of thermal energy. Then, to absorb a total of 5×10 7 Joules of heat per second, only 25 kg of water needs to be evaporated and gasified in the high altitude per second. Lifting 25 kg of water to a height of 70 m (the height of the fan hub), the gravitational potential energy that needs to be overcome per second is only 17500 W, which is 1 / 9 of the wake optimization power gain. What remains to be done is how to accelerate the gasification process of water.

[0059] The lifted seawater is sprayed onto the relatively high-temperature unsaturated atmosphere (humidity) by a high-pressure atomization device (forming small droplets to increase the contact area between water and the liquid), so as to promote the gasification of seawater in the wake region at high altitude to achieve the phase change endothermic process. Generally speaking, the smaller the particle size, the higher the air temperature, the lower the air humidity, and the greater the wind speed, the more conducive it is to the gasification process of water droplets. Therefore, the present invention essentially uses the latent heat of phase change of seawater in a circuitous and ingenious way to improve the power generation efficiency of the wake turbine. For offshore wind turbines, the feasibility of this solution is very high because seawater is easily accessible; for onshore wind turbines, to implement this solution, a wind farm close to a water source is considered. The overall schematic diagram is as Figure 7 shown. Figure 7 At the same time, it shows the working principle of the seawater spray system. By spraying atomized water droplets, the temperature of the wake air is reduced and its density is increased, thereby increasing the wind speed and improving the inflow conditions of the downstream wind turbine. Figure 7 In the figure, b1 represents the inflow wind speed entering the wind turbine area, b2 represents the wake area, b6 represents pumping water from seawater and supplying it to the high-pressure atomization device, b7 represents the high-pressure atomization device spraying water droplets, atomizing and spraying seawater into the wake area. b8 represents the air sinking formed by the gasification of water droplets to reduce the temperature. Since the sprayed water droplets absorb heat during gasification in the wake area, the air temperature drops and the density increases, prompting the air to sink. b9 represents accelerating the upper-layer wind speed into the wake area. After the sprayed water droplets are gasified and cooled, the process of inducing the upper-layer high-speed wind air into the wake area.

[0060] In the preferred embodiment, the atomization spraying range in the area behind the nacelle satisfies not less than 100m 2 ; the water droplet flow rate sprayed per second can be adjusted according to actual needs, and the flow rate range is 0 - 25 Kg / s. If it is a wind farm more severely affected by the wake, the flow rate range can be increased to 0 - 50 Kg / s; the particle size range of the water droplets is between 0.1mm and 0.2mm. Using too large a particle size will excessively reduce the evaporation efficiency, and using too small a particle size will excessively increase the atomization cost. After calculation, the particle size range between 0.1mm and 0.2mm is the best choice; preferably, the air temperature when spraying water droplets is not lower than 285K, otherwise the gasification effect will be greatly reduced. The above are all range references obtained from simulation experiments.

[0061] During the test, on the basis of the original wind field simulation, the simulation of the gasification phase change process of water droplets in the air was added, and the DPM module in FLUENT was used. 25 Kg of water droplets are injected per second in a 40m×40m rectangular area behind the wind turbine nacelle. The particle size of the water droplets is 0.0001m (0.1mm), the temperature of the water droplets is 295K (5K lower than the air temperature), the ejection flow rate is 5m / s, and the inflow air is dry air. Use the DPM (Discrete Phase Model) in the FLUENT software to set the injection parameters of the discrete phase (such as water droplets).

[0062] It is found through calculation that the wake reduction degree and the effect of increasing air density generated by injecting water droplets using DPM are almost the same as those of only introducing the heat source term of suction before, as Figure 8 shown. And only by setting up a seawater spraying device in the wake area of the inflow fan, the influence of the wake on the fan power at the second and third wakes can be reduced simultaneously.

[0063] In addition, this scheme can also greatly reduce the turbulent kinetic energy in the wake, thereby reducing the fatigue load on the blades of the rear-row fans, as Figure 9 shown. This effect can improve the service life of the fan to a certain extent and reduce the maintenance cost.

[0064] In the scenario studied in the present invention, the seawater temperature is lower than the atmosphere, and the air density in the lower layer close to the sea surface is greater than that in the upper layer, belonging to the stable atmospheric condition (SBL). Therefore, the inhibitory effect of the buoyancy effect on the wake recovery also needs to be considered. At this time, the influence of the wake effect is greater than that under the neutral stable condition. At the same time, it should also be considered that the sea-air is in a state of relatively high humidity, which will be disadvantageous to the gasification process of water droplets to a certain extent. Therefore, the present invention conducts a numerical simulation that is more in line with the actual situation of the offshore wind farm. The buoyancy effect is considered during the simulation process, and the original dry air is set to a relative humidity of 70%. Compared with the ideal situation, the buoyancy effect limits the sinking of the wake air to a certain extent, as Figure 10 shown, and its vertical velocity is less than Figure 8 the result shown in. Even so, the proposed wake control method can still bring a very considerable power increase to the downstream fans, as Figure 11 shown.

[0065] In view of the fact that the Reynolds-averaged Navier-Stokes (RANS) method will overestimate the wake recovery process, the large eddy simulation (LES) technology is used for further research. In the large eddy simulation, the simulation is carried out for the actual layout of the HornsRev wind farm. The simulation area is as Figure 12 shown, and a total of 8 2MW fans under a 270° wind direction are simulated.

[0066] When the wind speed is 8 m / s and the air temperature is 300 K, the wind farm power before and after using the wake optimization control device proposed in the present invention at the first fan is as Figure 13 shown. It can be found that in the results obtained from the large eddy simulation, the wake optimization effect of the present invention is more significant. The wake optimization effect of only using the present invention at the first fan is sufficient to increase the power of the second fan by 0.17 MW, and the increase amplitude is close to 60% of the original power. There is also a certain improvement effect on the subsequent fans. Finally, the total power of the fan array is increased by more than 0.2 MW, and this power increase also far exceeds the power consumption generated by the wake optimization device.

[0067] The present invention is applicable not only to offshore wind farms but also to onshore wind farms with sufficient water sources. After calculations under multiple working conditions, the range of applicable scenarios has been obtained. When the wind speed at the hub height is not lower than 4 m / s, the temperature is not lower than 285 K (12 °C), and the relative air humidity is not greater than 80%, the effects can be fully exerted. Moreover, such scenarios account for more than half of the whole year in most regions, indicating that the present invention is not only feasible in specific scenarios but has a broader range of applicable scenarios.

[0068] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several alternatives or modifications can be made to the described embodiments, and these alternative or modified forms should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "preferred embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the protection scope of the patent application.

Claims

1. A wind turbine wake active control optimization system, characterized in that: include: A water supply device, used for supplying water to the high-pressure atomizing device; The high-pressure atomization device is arranged at the position of the fan hub nacelle and is connected to the water supply device, and is used to atomize water and spray it into the wake area, wherein the sprayed atomized water droplets realize gasification phase change and heat absorption in the wake area, reduce the temperature of the wake air and increase its density, and the wake air generates a downward component velocity, inducing the high wind speed air above the wake area to replenish downward, and guiding the upper high wind speed to the wake area, thereby increasing the wind speed in the wake area and improving the inflow conditions of the downstream fan; A control unit is used to control the operation of the water supply device and the high-pressure atomization device, including controlling the water extraction volume, the spraying parameters of the atomized water droplets, and the operating state of the wake induction, so as to optimize the wind speed distribution in the wake area and improve the inflow wind speed and power generation efficiency of the downstream wind turbine.

2. The wind turbine wake active control optimization system according to claim 1, characterized in that: The wind turbine is an offshore wind turbine, and the water source supply device includes a seawater extraction device for extracting seawater and conveying it to the high-pressure atomization device.

3. The wind turbine wake active control optimization system according to claim 2, characterized in that: The seawater extraction device includes a seawater filtering device, a water supply high-pressure pump and a vacuum pump, and is installed around the wind turbine tower on the sea surface, wherein the seawater filtering device is used to filter seawater, the water supply high-pressure pump is used to transport the filtered seawater to the high-pressure atomization device, and the vacuum pump is used to extract seawater.

4. The wind turbine wake active control optimization system according to claim 1, characterized in that: The high-pressure atomization device includes an atomization high-pressure pump and an atomization nozzle assembly, wherein the atomization high-pressure pump is used to pressurize and deliver the liquid working medium to the atomization nozzle assembly; the atomization nozzle assembly includes a plurality of atomization nozzles, and the plurality of atomization nozzles are evenly distributed in a preset area behind the cabin and are connected to the atomization high-pressure pump through a water supply pipeline.

5. The wind turbine wake active control optimization system according to claim 4, characterized in that: The rated flow rate of the atomizing high-pressure pump meets the spraying process of atomized water droplets with a particle size of 0.1mm~0.2mm at 0~25kg / s.

6. The wind turbine wake active control optimization system according to claim 4, characterized in that: The atomizing nozzle is connected to the atomizing high-pressure pump through a water supply pipe, and the flow rate of a single atomizing nozzle is 3-6 liters / minute.

7. The wind turbine wake active control optimization system according to claim 1, characterized in that: The spraying range of the high-pressure atomizing device in the rear area of ​​the cabin is not less than 100m 2 ; The flow rate of water droplets sprayed per second ranges from 0 to 50 Kg / s; the particle size of water droplets ranges from 0.1 mm to 0.2 mm; the air temperature when spraying water droplets is not lower than 285 K.

8. A method for optimizing active wind turbine wake control, characterized in that: Active fan wake control optimization is performed using the fan wake active control optimization system according to any one of claims 1 to 7, wherein atomized water droplets are sprayed into the wake area of ​​the fan, the density of the wake air increases after cooling, and a downward component velocity is generated in the wake area. After the wake air sinks, the high-speed air above the wake area is induced to enter the wake area to supplement the sinking air, thereby increasing the wind speed in the wake area and improving the inflow conditions of the downstream fan.

Images