Lifting type vortex generator and lifting regulation and control method

Abstract

The invention provides a lifting type vortex generator and a lifting regulation and control method, and belongs to the field of active flow control and equipment. In the vortex generator VG, a base is arranged on a web plate; a motor is fixed to the base and connected with one end of a rocker, the other end of the rocker is hinged to one end of a connecting rod, an insertion hole is formed in the free end of the connecting rod, and the support is perpendicular to the connecting rod and inserted into the insertion hole. The VG bodies are symmetrically distributed on the support in pairs with the connecting rod as the center, a hollow groove is reserved in the suction surface, a pin is arranged in the hollow groove, the VG bodies are hinged to the pin, and the height is adjusted and controlled within the range of 0% and 1.5% of the chord length of the current blade element in the hollow groove with the pin as the center; during lifting regulation and control, an attack angle-height optimization model is constructed according to the optimal lift-drag ratio; and outputting a corresponding optimal VG body height based on the calculated attack angle, and controlling the VG body through a motor. According to the vortex generator, the lift-increasing and drag-reducing effects are improved, and the power generation power is increased.

Description

Technical Field

[0001] The present invention belongs to the field of active flow control and equipment, and particularly relates to a lifting type vortex generator and a lifting control method. Background Art

[0002] Vortex generators are commonly used components in aerodynamics, and are generally applied to aircraft, blades of wind turbines, etc. For wind turbines, when the blade is at a large angle of attack, air flow separation will occur on the surface, resulting in a series of adverse consequences such as reduced lift, increased drag, and reduced maneuverability and stability. Vortex generators are one of the most commonly used means to suppress flow separation at present and have been applied to blades of many models.

[0003] Generally, a vortex generator is a small protrusion vertically installed on the blade surface. Its effective part can be regarded as a thin plate with a very small aspect ratio. Common shapes include triangles, rectangles, trapezoids, etc. The plane where it is located has a certain angle with the oncoming flow direction. Since the aspect ratio of the vortex generator is very small, a strong tip vortex can be generated. This tip vortex can promote the mixing of low-energy air flow inside the boundary layer and high-energy air flow outside the boundary layer, thereby increasing the energy of the boundary layer air flow. As the energy of the air flow in the boundary layer increases, a stronger ability to resist the adverse pressure gradient is obtained, so the flow separation of the boundary layer is suppressed.

[0004] In the prior art, the vortex generator is arranged on the blade surface, and generally it is fixed both in terms of the installation angle and the installation height; however, the blade element has different parameters such as Reynolds number and angle of attack under different working conditions, and the boundary layer thickness and air flow direction at the same position will also change accordingly, and the effect generated by the vortex generator will also change accordingly. A fixedly installed vortex generator cannot achieve the effect of suppressing flow separation under all working conditions; in addition, traditional vortex generators are designed for the working conditions of large angles of attack, and there are small angles of attack in the working state of the blade. Traditional vortex generators cannot play a role in this state, and even have a negative effect, bringing additional resistance to the vortex generator itself and reducing the lift-drag ratio. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present invention aims to provide a lifting type vortex generator and a lifting control method. Based on wind turbine blades, the vortex generator is combined with an optimization algorithm. Starting from dynamic adaptability, intelligence and efficiency, with sensors as the medium and motors as the drive, the installation height of the vortex generator is adjusted in real time according to the oncoming flow conditions (such as angle of attack, wind speed, etc.), so as to avoid increased power loss at small angles of attack and improve the flow control effect of the vortex generator at large angles of attack by designing an active vortex generator, reduce unnecessary power loss, and optimize the aerodynamic performance of wind turbine blades.

[0006] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0007] In a first aspect, the embodiments of the present invention provide a lift-type vortex generator (VG). The lift-type sector-shaped VG is disposed on the suction surface of a predetermined blade element 8 of a fan blade, and includes: a VG body 1, a bracket 2, a connecting rod 3, a rocker 4, a base 5, a motor 6, and a pin 9; wherein,

[0008] The base 5 is disposed on an internal web 7 that intersects and is fixedly connected to the suction surface; a motor 6 is fixed on the base; one end of the motor 6 is connected to one end of the rocker 4, and the other end of the rocker 4 is hinged to one end of the connecting rod 3; the free end of the connecting rod 3 has a jack; the bracket 2 is an elongated rod, inserted into the jack at the free end of the connecting rod 3, perpendicular to the connecting rod 3, and symmetrically distributed on both sides of the jack with the jack as the center, and parallel to the suction surface; the VG body 1 is disposed on the bracket 2 in pairs and symmetrically with the jack of the connecting rod 3 as the center; a hollow groove is provided on the suction surface of the blade element 8 opposite to the VG body 1, and the VG body 1 passes through the corresponding hollow groove and extends or retracts from the hollow groove within a defined range. Preferably, the hollow groove is provided at the 20% chord position; the adjustable height value of the VG body within the hollow groove with the pin as the center is 0 to 1.5% of the current blade element chord length.

[0009] Preferably, the VG body includes at least a first body and a second body, which are distributed in pairs and symmetrically on the bracket.

[0010] As a preferred embodiment of the present invention, the VG body 1 is sector-shaped, with a first through-hole at the center of the sector and a second through-hole at one of the edge angles; a pin 9 is provided in each hollow groove of the suction surface, and the pin 9 passes through the first through-hole of the sector of the VG body 1, and the VG body 1 rotates around the pin 9 within the hollow groove; the second through-hole of the sector of the VG body 1 penetrates through the bracket 2, and the other opposite edge angle extends or retracts from the suction surface within the hollow groove of the suction surface.

[0011] As a preferred embodiment of the present invention, the pin 9 is installed at the upper edge, lower edge, or middle position of the hollow groove.

[0012] As a preferred embodiment of the present invention, the vortex generator further includes: a data request module 10, an angle of attack calculation module 11, an optimization module 12, and a motor control module 13, all of which are disposed on the same web 7 as the base 5; wherein,

[0013] The data request module 10 can exchange data with the fan control center and is also connected to the angle of attack calculation module 11 and the motor control module 13. The data request module 10 is used to preset angle of attack points within the range of the local inflow angle of attack of the blade element, preset VG body height points within the range of the VG body height, collect all the angle of attack points corresponding to each VG body height point, as well as the corresponding lift and drag characteristics, to form an original data set, and send it to the angle of attack calculation module 11. It is also used to collect the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the liftable vortex generator is located, and is also used to upload the motor control data of the motor control module 13 to the fan control center;

[0014] The angle of attack calculation module 11 is also connected to the optimization module 12, and is used to calculate the local inflow angle of attack of the blade element according to the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the current liftable vortex generator is located. It is also used to determine whether the current angle of attack is the same as the angle of attack at the previous moment. If they are the same, it waits until the next moment and starts the data request module. If they are not the same, it starts the optimization module 12 and sends the calculated angle of attack to the optimization module 12 at the same time;

[0015] The optimization module 12 is connected to the motor control module 13, and is used to find the optimal VG body height value at each angle of attack point based on the original data set with the best lift-to-drag ratio as the objective function. It constructs an optimization model based on the angle of attack and the optimal VG body height. It is also used to determine the optimal VG body height according to the angle of attack and the optimization model, and feedback the optimal VG body height to the motor control module 13;

[0016] The motor control module 13 is used to control the motor using the PID algorithm according to the optimal VG body height, drive the VG body to move to the optimal VG body height, wait until the next moment, and start the data request module 10. At the same time, it sends the motor control data to the data request module 10 in real time.

[0017] In a second aspect, an embodiment of the present invention also provides a lifting control method for a liftable vortex generator, and the method is used to control the liftable vortex generator as described above. The lifting control method includes:

[0018] Step S1, preset angle of attack points within the range of the local inflow angle of attack of the blade element, preset VG body height points within the range of the VG body height, collect all the angle of attack points corresponding to each VG body height point, as well as the corresponding lift and drag characteristics, to form an original data set;

[0019] Step S2, based on the original data set, with the best lift-to-drag ratio as the objective function, find the optimal VG body height value at each angle of attack point; construct an optimization model based on the angle of attack and the optimal VG body height;

[0020] Step S3: Collect the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the lift-type vortex generator is located, and calculate the angle of attack of the blade element inflow.

[0021] Step S4: Determine whether the current angle of attack is the same as the angle of attack at the previous moment; if they are the same, wait until the next moment and return to Step S3; if they are different, proceed to Step S5.

[0022] Step S5: Input the calculated current angle of attack value into the optimization model, and output the optimal VG body height corresponding to the current angle of attack value.

[0023] Step S6: According to the optimal VG body height, use the PID algorithm to control the motor and drive the VG body to move to the optimal VG body height; wait until the next moment and return to Step S3.

[0024] As a preferred embodiment of the present invention, Step S2 further includes: using the interpolation method to expand the basic data set to obtain a smoother and more continuous data set, and improving the accuracy and precision of the optimization model.

[0025] As a preferred embodiment of the present invention, for the construction of the optimization model in Step S2, an optimal height analysis table is established as the optimization model.

[0026] As a preferred embodiment of the present invention, for the construction of the optimization model in Step S2, according to the angle of attack and the optimal VG body height, with the angle of attack as the independent variable and the optimal VG body height as the dependent variable, function fitting is performed, and the continuous function obtained after fitting is used as the optimization model.

[0027] As a preferred embodiment of the present invention, the process of calculating the angle of attack of the blade element inflow in Step S3 is as follows:

[0028] Calculate the current blade element inflow velocity v according to formula (1) r :

[0029]

[0030] In formula (1), v ∞ represents the oncoming flow velocity, Ω represents the blade rotation speed, a represents the axial induction factor, a′ represents the tangential induction factor, and r represents the blade element radial position;

[0031] Then calculate the suction surface angle of attack α according to formula (2):

[0032]

[0033] In formula (2), θ represents the sum of the blade element twist angle and the blade pitch angle.

[0034] As a preferred embodiment of the present invention, step S4 determines whether the current angle of attack is the same as that of the previous moment. The judgment logic is as follows: If the ratio of the difference between the current angle of attack and the angle of attack of the previous moment to the angle of attack of the previous moment is greater than a preset threshold, it is judged to be inconsistent; otherwise, it is judged to be consistent.

[0035] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0036] The lift-type vortex generator and the lift control method provided by the embodiment of the present invention can accurately control the generation and distribution of vortices on the surface of the wind turbine blade by actively adjusting the height of the vortex generator, optimize the aerodynamic performance of the wind power generation unit, reduce flow separation, increase the wind energy captured by the blade, thereby improving the power generation efficiency and output power of the entire wind turbine, solving the problem of reduced power generation efficiency sometimes caused by passive vortex generators on the market, and improving the utilization efficiency of wind energy resources; at the same time, it improves the adaptability and stability to wind energy resources, can dynamically adjust the vortex generation according to different wind speed conditions, enables the wind turbine to operate efficiently within a wide wind speed range, improves the adaptability of the wind turbine, and the vortex generator can also reduce mechanical vibration and noise during wind power generation to a certain extent, improving the operation stability and reliability of the wind turbine; in addition, by increasing the power generation of the wind turbine, the operation cost per unit of electricity is reduced to a certain extent, and by reducing flow separation and mechanical vibration, the service life of the wind turbine components is extended, and the maintenance cost caused by frequent maintenance and component replacement is reduced.

[0037] Of course, it is not necessary for any product or method implementing the present invention to achieve all the above advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 is a first perspective schematic diagram of the structure and installation effect of the lift-type vortex generator according to the embodiment of the present invention;

[0040] Figure 2 is a second perspective schematic diagram of the structure and installation effect of the lift-type vortex generator according to the embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of the geometric main structure of the lift-type vortex generator according to the embodiment of the present invention;

[0042] Figure 4 isFigure 2 Schematic diagram of the position of the pin after magnifying the A part in the middle;

[0043] Figure 5 Schematic diagram of the position of the lift-type vortex generator according to the embodiment of the present invention at a large angle of attack;

[0044] Figure 6 Schematic diagram of the position of the lift-type vortex generator according to the embodiment of the present invention at a small angle of attack;

[0045] Figure 7 Flowchart of the lift control method of the lift-type vortex generator according to the embodiment of the present invention;

[0046] Figure 8 Force analysis diagram of the blade in the lift control method according to the embodiment of the present invention;

[0047] Figure 9 Percentage of power improvement of the lift-type vortex generator according to the embodiment of the present invention at different tip speed ratios of a 5MW wind turbine when ignoring the leading edge roughness;

[0048] Figure 10 Percentage of power improvement of the lift-type vortex generator according to the embodiment of the present invention at different tip speed ratios of a 5MW wind turbine when considering the leading edge roughness.

[0049] Description of reference numerals:

[0050] 1 - VG body; 2 - bracket; 3 - connecting rod; 4 - rocker; 5 - base; 6 - motor; 7 - web; 8 - blade element; 9 - pin; 10 - data request module; 11 - angle of attack calculation module; 12 - optimization module; 13 - motor control module. Detailed implementation manner

[0051] After discovering the above problems, the inventors of this application have conducted a detailed study on the existing vortex generator technology based on the blades of wind turbines (hereinafter referred to as wind turbines). The study found that the angle of attack of the blade and the height H of the vortex generator extending from the blade surface have an important influence on the performance of the vortex generator (VG). The installation height objectively increases the windward area of ​​the blade, resulting in an increase in resistance at a small angle of attack. Specifically, under the condition of a small angle of attack of the blade, the vortex generator does not contact the local airflow, or the vortex generator does not extend from the blade surface to minimize the resistance caused by the vortex generator. This state of the vortex generator is called the zero position. As the blade angle of attack increases, the airflow tends to flow separation, driving the rocker device to rotate around the axis, driving the vortex generator up and down, obtaining the height of the vortex generator that matches the thickness of the boundary layer and the appropriate installation angle with the local airflow, and generating vortices of sufficient strength to suppress flow separation. When the blade leaves the large angle of attack state and the angle of attack state tends to decrease, the drive mechanism moves in the opposite direction to restore the vortex generator to the zero position. The inhibitory effect of the vortex generator on airflow separation is directly related to its height. The height of the vortex generator should be close to the local boundary layer thickness. If the height of the vortex generator extending from the blade surface is too low, the generated vortex is weak and the flow control effect is weak. If the height of the vortex generator extending from the blade surface is too high, the generated drag is too large, resulting in a decrease in the overall aerodynamic efficiency and an unsatisfactory control effect. In addition, the boundary layer thickness of the same part of the blade is different at different angles of attack, and different installation schemes of the vortex generator have different effects on the lift-to-drag ratio. For example, Figure 1 As shown in the figure, at a small angle of attack, the scheme with an installation height of 0 mm has a higher lift-to-drag ratio; while at a large angle of attack, the scheme with an installation height of 10 mm has a higher lift-to-drag ratio. It can be seen that the optimal vortex generator installation height is different at different angles of attack. In order to maximize the effectiveness of the vortex generator, the height of the vortex generator should be dynamically adjusted according to the local boundary layer thickness, so that the parameters can be adjusted according to different flight conditions.

[0052] According to the above analysis, the embodiments of the present invention improve the traditional vortex generator. The improved vortex generator not only has a simple structure, but also can adjust the height of the vortex generator extending out of the blade surface, thereby solving the above-mentioned shortcomings.

[0053] It should be noted that the defects existing in the solutions in the above-mentioned prior art are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above-mentioned problems and the solutions proposed in the embodiments of the present invention for the above-mentioned problems below should all be the contributions made by the inventor to the present invention in the process of the present invention.

[0054] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can also be combined with each other.

[0055] It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the present invention, the terms "first", "second", "third", "fourth", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0056] After the above in-depth analysis, the embodiments of the present invention provide a lifting type vortex generator and a lifting control method. Based on the blades of a wind turbine (hereinafter referred to as a wind turbine), the vortex generator is combined with an optimization algorithm. Starting from dynamic adaptability, intelligence, and efficiency, with a sensor as a medium and a motor as a drive, the installation height of the vortex generator is adjusted in real time according to the oncoming flow conditions (such as the angle of attack, wind speed, etc.), so as to avoid the increased power loss at a small angle of attack, improve the flow control effect of the vortex generator at a large angle of attack, reduce unnecessary power loss, and optimize the aerodynamic performance by designing an active vortex generator.

[0057] As Figures 2 to 5 shown, the lifting type vortex generator VG provided by the embodiments of the present invention, the VG is arranged on the suction surface of a predetermined blade element 8 of the wind turbine blade, and includes: a VG body 1, a bracket 2, a connecting rod 3, a rocker 4, a base 5, a motor 6, a pin 9, a data request module 10, an angle of attack calculation module 11, an optimization module 12, and a motor control module 13.

[0058] Among them, the base 5 is arranged on the inner web 7 that intersects and is fixedly connected to the suction surface of the blade element 8; a motor 6 is fixed on the base 5; the motor 6 is connected to one end of the rocker 4, and the other end of the rocker 4 is hinged to one end of the connecting rod 3; the free end of the connecting rod 3 has a jack; the bracket 2 is a slender rod, inserted into the jack at the free end of the connecting rod 3, perpendicular to the connecting rod 3, and evenly distributed on both sides of the jack with the jack as the center, and parallel to the suction surface; the VG body 1 is arranged on the bracket 2 in pairs and symmetrically with the jack of the connecting rod 3 as the center; a hollow groove is arranged on the suction surface opposite to the VG body 1, and the VG body 1 passes through the corresponding hollow groove and can extend or retract into the hollow groove within a limited range. Preferably, the hollow groove is arranged at the 20% chord position; the adjustable height value of the VG body inside the hollow groove with the pin as the center is 0 to 1.5% of the current blade element chord length. In a specific embodiment, the VG body 1 is fan-shaped, with a first through hole at the center of the fan, and a second through hole at one of the edge angles; a pin 9 is arranged in each hollow groove of the suction surface, and the pin 9 passes through the first through hole of the fan-shaped VG body 1, and the VG body 1 rotates around the pin 9 in the hollow groove; the second through hole of the fan-shaped VG body 1 penetrates through the bracket 2, and the other free edge angle extends or retracts from the suction surface in the hollow groove of the suction surface. As Figure 4 and Figure 5 shown, the pin 9 can be installed at the upper edge, lower edge or middle position of the hollow groove.

[0059] At this time, the motor 6 fixed on the base 5 drives the rocker 4 to rotate, the rocker 4 drives the connecting rod 3 to move up and down, the connecting rod 3 drives the bracket 2 to move up and down horizontally, pulls one of the edge angles of the fan-shaped VG body 1 through the second through hole, makes the VG body 1 rotate with the pin 9 as the center of the circle, and the other free edge angle of the VG body 1 is the highest point extending from the suction surface. At this time, the free edge angle moves up and down in the hollow groove, so as to adjust the height of the vortex generator.

[0060] The vortex generator further includes: a data request module 10, an angle of attack calculation module 11, an optimization module 12 and a motor control module 13, and are all arranged on the same web 7 as the base 5.

[0061] Among them, the data request module 10 can exchange data with the fan control center in a wireless or wired manner, and is electrically connected to the angle of attack calculation module 11 and the motor control module 13 at the same time; the data request module 10 is used to preset angle of attack points within the range of the blade element inflow angle of attack, preset VG body height points within the range of the VG body height, collect all the angle of attack points corresponding to each VG body height point, and the corresponding lift-drag ratio, to form an original data set, and send it to the angle of attack calculation module 11; it is also used to collect the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the lift-type vortex generator is located, and is also used to upload the motor control data of the motor control module 13 to the fan control center;

[0062] The angle of attack calculation module 11 is connected to the optimization module 12, and is used to calculate the blade element inflow angle of attack according to the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the current lift-type vortex generator is located; it is also used to judge whether the current angle of attack is the same as the angle of attack at the previous moment; if they are the same, wait until the next moment and start the data request module 10; if they are different, start the optimization module 12, and at the same time send the calculated angle of attack to the optimization module 12;

[0063] The optimization module 12 is connected to the motor control module 13, and is used to find the optimal VG body height value at each angle of attack point based on the original data set with the best lift-drag ratio as the objective function; construct an optimization model based on the angle of attack and the optimal VG body height; it is also used to determine the optimal VG body height according to the angle of attack and the optimization model, and feedback the optimal VG body height to the motor control module 13;

[0064] The motor control module 13 is used to control the motor by using the PID algorithm according to the optimal VG body height, and drive the VG body to move to the optimal VG body height; wait until the next moment and start the data request module 10; at the same time, send the motor control data to the data request module 10 in real time.

[0065] As Figure 6 shown, when the blade element 8 of the blade is in the condition of a large angle of attack α and flow separation on the suction surface, the VG body 1 extends out of the suction surface of the blade, so that the VG body 1 is in a working state, thereby effectively suppressing the flow separation on the suction surface under the condition of a large angle of attack and improving the aerodynamic performance of the fan blade.

[0066] As Figure 7 shown, when the blade element 8 of the blade is in the condition of a small angle of attack α and no flow separation on the suction surface, the VG body 1 on the suction surface of the blade element 8 does not extend out, thereby avoiding the additional form drag and vortex drag generated by the vortex generator.

[0067] Based on the same idea, an embodiment of the present invention also provides a lifting control method based on the lifting type vortex generator. As Figure 8 shown, the lifting control method of the lifting type vortex generator includes the following steps:

[0068] Step S1, preset angle of attack points within the inflow angle of attack range of the blade element, preset VG body height points within the VG body height range, collect all angle of attack points corresponding to each VG body height point, and the corresponding lift-drag ratio, and form an original data set.

[0069] In this step, the data is collected by the data request module to request historical data from the fan control center, or the corresponding data is obtained through experiments based on the preset angle of attack points and VG body height points.

[0070] Step S2, based on the original data set, with the best lift-drag ratio as the objective function, find the optimal VG body height value at each angle of attack point; construct an optimization model based on the angle of attack and the optimal VG body height.

[0071] In this step, the optimization model can be constructed by establishing an optimal height analysis table as the optimization model; it can also be based on the angle of attack and the optimal VG body height, with the angle of attack as the independent variable and the optimal VG body height as the dependent variable, perform function fitting, and use the continuous function obtained after fitting as the optimization model. At this time, the optimization model is a continuous curve function based on the angle of attack and the optimal VG body height.

[0072] Preferably, this step may further include: using the interpolation method to expand the basic data set to obtain a smoother and more continuous data set, and improve the accuracy and precision of the optimization model. The interpolation method includes, but is not limited to, cubic spline interpolation, etc.

[0073] Preferably, the lift-drag ratio is characterized by the ratio of the lift coefficient or the drag coefficient.

[0074] Step S3, collect the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the lifting type vortex generator is located, and calculate the inflow angle of attack of the blade element.

[0075] In this step, the oncoming flow velocity and blade rotation speed are generally obtained by the wind speed and rotation speed sensors arranged on the suction surface.

[0076] As Figure 9 shown, perform a force analysis on the blade, and thus the process of calculating the inflow angle of attack of the blade element is as follows:

[0077] Calculate the current inflow velocity v of the blade element according to formula (1) r :

[0078]

[0079] In Equation (1), v ∞ represents the oncoming flow velocity, Ω represents the blade rotational speed, a represents the axial induction factor, a′ represents the tangential induction factor, and r represents the radial position of the blade element.

[0080] Then, calculate the suction surface angle of attack α according to Equation (2):

[0081]

[0082] In Equation (2), θ represents the sum of the blade element twist angle and the blade pitch angle.

[0083] Step S4: Determine whether the current angle of attack is the same as that at the previous moment; if it is the same, wait until the next moment and return to Step S3; if it is not the same, enter Step S5.

[0084] In this step, the judgment logic for whether they are the same is as follows: If the ratio of the difference between the current angle of attack and the angle of attack at the previous moment to the angle of attack at the previous moment is greater than the preset threshold, it is judged as inconsistent; otherwise, it is judged as consistent. The preset threshold is set according to the actual situation. For example, it is 2%.

[0085] Preferably, the current moment and the previous moment are set according to the actual operating conditions of the blade. They can be set as data acquisition points at equal time intervals, or can be set by calculating the corresponding time length according to the same blade rotation angle intervals.

[0086] Step S5: Input the calculated current angle of attack value into the optimization model, and output the optimal VG body height corresponding to the current angle of attack value.

[0087] Step S6: According to the optimal VG body height, use the PID algorithm to control the motor to drive the VG body to move along the belt guide rail, so that the VG body moves to the optimal VG body height; wait until the next moment and return to Step S3.

[0088] As described above, the lift - type vortex generator according to the embodiment of the present invention can be applied to various design structures that conform to the aerodynamic principle, such as aircraft, automobiles, or wind turbine blades. Taking the blades of a wind turbine as an example, the lift - type vortex generator is designed on the inner side of the suction surface of the blade element. Based on different blade angles of attack, a set of height values of the vortex generator protruding from the blade element surface are obtained. Within the preset search space, the height of the vortex generator is repeatedly searched, and further analysis is carried out to obtain the protruding height required for the vortex generator to exert the optimal efficiency under different operating conditions of the blade.

[0089] Perform performance evaluation on the blade installed with the lift - type vortex generator according to the embodiment of the present invention. The evaluation process is as follows:

[0090] Adopt the data shown in Table 1:

[0091] Table 1

[0092]

[0093] Preferably, the data in Table 1 can also be pre - processed to construct a smoother and more continuous data set, so as to obtain a height search result closer to the optimal value.

[0094] According to the data acquisition or request in Table 1 for the oncoming flow wind speed, blade rotation speed, blade pitch angle, element twist angle, and element radial position, calculate the angle of attack. In the states of large and small angles of attack, the vortex generator is in different working states, that is, it has different optimal heights. When the blade or element 8 is in the condition of a large angle of attack α and there is flow separation on the suction surface, the VG body 1 extends out of the suction surface of the blade, making the VG body 1 in the working state, so as to effectively suppress the flow separation on the suction surface under the condition of a large angle of attack and improve the aerodynamic performance of the blade; when the element 8 is in the condition of a small angle of attack α and there is no flow separation on the suction surface, the VG body 1 on the suction surface of the element 8 does not extend out, thus avoiding the additional form drag and vortex drag generated by the vortex generator. Therefore, based on the original data in Table 1 and the relevant data collected or requested, find the optimal height values of the vortex generator body at different angles of attack, and adjust the height of the vortex generator differently at different angles of attack of the blade, so as to improve the power generation efficiency and output power of the whole wind turbine.

[0095] In order to evaluate the effect of height adjustment, evaluate the power load of the wind turbine, and the evaluation process is as follows:

[0096] As Figure 9 shown, select a certain type of wind turbine for force analysis. It is known that the length of the wind turbine blade is R, and according to the linear interpolation carried out in the data optimization, obtain the sum θ of the twist angle and the blade pitch angle and the chord length c at different element radial positions r.

[0097] The dynamic pressure q under the radial velocity ∞ (the density is the density under standard atmospheric pressure) can be obtained from the following formula (3):

[0098]

[0099] In formula (3), ρ represents the air density.

[0100] Also from the following formulas (4), (5):

[0101] L = q ∞ ·C l ·c (2)

[0102] D = q ∞ ·C d ·C (3)

[0103] In equations (4)-(5), L represents lift, D represents drag, C l represents the lift coefficient, C d represents the drag coefficient, and c represents the chord length.

[0104] The lift L and drag D can be obtained.

[0105] The moment calculation formulas (6), (7), and (8) per unit chord length are as follows:

[0106] T = L sin(θ + α) - D cos(θ + α) (4)

[0107] N = L cosα + D cosα (5)

[0108] T q = N sinθ + T cosθ (6)

[0109] In equations (6)-(8), T represents the tangential force component of the chord length on the blade element, N represents the normal force component of the chord length on the blade element, and T q represents the in-plane force component of a single blade along the wind turbine plane.

[0110] By integrating the radius of T q ·r, the torque M can be obtained, as shown in equation (9):

[0111]

[0112] In equation (9), R represents the radius of the wind turbine.

[0113] Finally, according to equation (10):

[0114] P = M·Ω (8)

[0115] The magnitude of the power P is obtained.

[0116] The tip speed ratio λ is a key parameter in wind turbine design and performance analysis. It is equal to the ratio of the linear speed at the tip of the wind turbine blade to the wind speed. From the defining equation, it can be seen that the wind speed is inversely proportional to the tip speed ratio. Since the wind speed and the angle of attack are positively correlated, it means that the smaller the angle of attack, the larger the tip speed ratio. The relationship is as follows:

[0117] Tip speed ratio:

[0118] Tip linear speed: v tip = Ω·R (12)

[0119] Perform load assessment according to the power load assessment process described above. Taking the results obtained at different tip speed ratios of the NREL 5MW wind turbine as an example for illustration.

[0120] As Figure 10 shown, without considering the leading edge roughness, when λ = 9, the power increase percentage of the lift-type vortex generator (0.78%) is still positive, while that of the passive vortex generator drops to a negative value (-0.11%); compared with the passive type, at a high tip speed ratio (λ = 12), the power loss of the lift-type vortex generator is -0.22%, almost completely compensating for the -2.58% power loss brought by the passive type.

[0121] When considering the leading edge roughness, the lift-type vortex generator reduces the negative impact of the leading edge roughness, and the effect is significant when the tip speed ratio is small. As Figure 10 shown, when λ = 7, the power loss without a vortex generator is 22.29%, while the power loss with a lift-type vortex generator is only 10.31%, which is equivalent to the effect of the passive vortex generator; as the tip speed ratio increases, the power increase effect of the vortex generator gradually weakens, but the lift-type vortex generator can further reduce the power loss caused by the leading edge roughness.

[0122] It can be seen from the above technical solutions that the lift-type vortex generator and the lift control method provided by the embodiments of the present invention realize the intelligent perception of the wind condition and the intelligent adjustment of the vortex generator through an active control system. The vortex generator obtains real-time wind speed data through a wind speed sensor, determines the optimal height position of the vortex generator using a preset optimization model, and controls the motor using a PID algorithm to drive the gear and a group of vortex generators installed in the suction surface gap to move up and down, so that the VG body moves to the optimal height state to play a flow control role; when the wind turbine blade is out of the large angle of attack state, the motor rotates in the reverse direction and the vortex generator is restored to the zero position, so as to maximize the lift-drag ratio and increase the power generation; at the same time, the structure of the vortex generator is simple and has strong universality, and can adapt to the requirements for the height of the vortex generator under different working conditions.

[0123] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles applied, and is not intended to limit the scope of the present invention claimed, but only represents the preferred embodiments of the present invention. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

Claims

1. A lift-type vortex generator, the lift-type vortex generator VG is arranged on the suction surface of a predetermined blade element (8) of a fan blade, and is characterized in that, The lift-type VG includes: a VG body (1), a bracket (2), a connecting rod (3), a rocker (4), a base (5), a motor (6), and a pin (9); among which, the base (5) is arranged on an internal web (7) that intersects and is fixedly connected to the suction surface; the motor (6) is fixed on the base; the motor (6) is connected to one end of the rocker (4), and the other end of the rocker (4) is hinged to one end of the connecting rod (3); the free end of the connecting rod (3) has a socket; the bracket (2) is a slender rod, inserted into the socket at the free end of the connecting rod (3), perpendicular to the connecting rod (3), and evenly distributed on both sides of the socket with the socket as the center, and parallel to the suction surface; the VG body (1) is arranged on the bracket (2) in pairs and symmetrically with the socket of the connecting rod (3) as the center; a hollow groove is arranged on the suction surface opposite to the VG body (1), and the VG body (1) passes through the corresponding hollow groove and extends or retracts from the hollow groove within a defined range.

2. The lift type vortex generator according to claim 1, wherein, The VG body (1) is fan-shaped, with a first through-hole at the center of the fan, and a second through-hole at one of the edge angles; a pin (9) is arranged in each hollow groove of the suction surface, and the pin (9) passes through the first through-hole of the fan-shaped VG body (1), and the VG body (1) rotates in the hollow groove around the pin (9); the second through-hole of the fan-shaped VG body (1) penetrates through the bracket (2), and the other opposite edge angle extends or retracts from the suction surface in the hollow groove of the suction surface.

3. The lift type vortex generator according to claim 2, wherein, The pin (9) is installed at the upper edge, lower edge or middle position of the hollow groove.

4. The lift type vortex generator according to claim 1, wherein The hollow groove is arranged at the 20% chord position; the adjustable height value of the VG body inside the hollow groove with the pin as the center is between 0 and 1.5% of the current blade element chord length.

5. The lift type vortex generator according to any one of claims 1-4, characterized in that, The vortex generator further includes: a data request module (10), an angle of attack calculation module (11), an optimization module (12), and a motor control module (13), all of which are arranged on the same web (7) as the base (5); among which, the data request module (10) can exchange data with the fan control center, and is connected to the angle of attack calculation module (11) and the motor control module (13) at the same time; the data request module (10) is used to preset angle of attack points within the range of the blade element inflow angle of attack, preset VG body height points within the range of the VG body height, collect all angle of attack points corresponding to each VG body height point, as well as the corresponding lift-to-drag ratio, to form an original data set, and send it to the angle of attack calculation module (11); it is also used to collect the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the lift-type vortex generator is located, and is also used to upload the motor control data of the motor control module (13) to the fan control center; The angle of attack calculation module (11) is also connected to the optimization module (12), and is used to calculate the inflow angle of attack of the blade element according to the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the current lift-type vortex generator is located; it is also used to determine whether the current angle of attack is the same as the angle of attack at the previous moment; if they are the same, wait until the next moment and start the data request module (10); if they are different, start the optimization module (12), and at the same time send the calculated angle of attack to the optimization module (12); The optimization module (12) is connected to the motor control module (13), and is used to find the optimal VG body height value at each angle of attack point based on the original data set with the best lift-to-drag ratio as the objective function; construct an optimization model based on the angle of attack and the optimal VG body height; it is also used to determine the optimal VG body height according to the angle of attack and the optimization model, and feedback the optimal VG body height to the motor control module (13); The motor control module (13) is used to control the motor by using the PID algorithm according to the optimal VG body height, drive the VG body to move to the optimal VG body height; wait until the next moment and start the data request module (10); at the same time, send the motor control data to the data request module (10) in real time.

6. A lifting control method for a lifting type vortex generator, characterized in that, The method is used to regulate the lift-type vortex generator according to any one of claims 1-5; the lift regulation method includes: Step S1, preset angle of attack points within the inflow angle of attack range of the blade element, preset VG body height points within the VG body height range, collect all angle of attack points corresponding to each VG body height point, and the corresponding lift-to-drag ratio, and form an original data set; Step S2, based on the original data set, with the best lift-to-drag ratio as the objective function, find the optimal VG body height value at each angle of attack point; construct an optimization model based on the angle of attack and the optimal VG body height; Step S3, collect the oncoming flow velocity, blade rotation speed, blade pitch angle, blade element twist angle, and blade element radial position in the blade environment where the lift-type vortex generator is located, and calculate the inflow angle of attack of the blade element; Step S4, determine whether the current angle of attack is the same as the angle of attack at the previous moment; if they are the same, wait until the next moment and return to Step S3; if they are different, enter Step S5; Step S5, input the calculated current angle of attack value into the optimization model, and output the optimal VG body height corresponding to the current angle of attack value; Step S6, according to the optimal VG body height, control the motor by using the PID algorithm, drive the VG body to move to the optimal VG body height; wait until the next moment and return to Step S3.

7. The lifting control method of the lifting type vortex generator according to claim 6, characterized in that, For the construction of the optimization model in Step S2, establish an optimal height analysis table as the optimization model.

8. The lifting control method of the lifting type vortex generator according to claim 6, characterized in that, For the construction of the optimization model in Step S2, according to the angle of attack and the optimal VG body height, with the angle of attack as the independent variable and the optimal VG body height as the dependent variable, perform function fitting, and use the continuous function obtained after fitting as the optimization model.

9. The lifting control method of the lifting type vortex generator according to claim 6, characterized in that, The process of calculating the inflow angle of attack of the blade element in Step S3 is as follows: Calculate the current blade element inflow wind speed v according to formula (1) r :[[-END]] In Equation (1), v ∞ represents the incoming flow wind speed, Ω represents the blade rotational speed, a represents the axial induction factor, a′ represents the tangential induction factor, and r represents the radial position of the blade element; Then calculate the suction surface angle of attack α according to formula (2): In formula (2), θ represents the sum of the blade element twist angle and the blade pitch angle.

10. The lifting control method of the lifting type vortex generator according to claim 6, characterized in that, Step S4 determines whether the current angle of attack is the same as that at the previous moment. The judgment logic is as follows: If the ratio of the difference between the current angle of attack and the angle of attack at the previous moment to the angle of attack at the previous moment is greater than the preset threshold, it is judged to be inconsistent; otherwise, it is judged to be consistent.

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