CN110080937B - Wind turbine blades for broadband active control - Google Patents

Abstract

The invention is a wind turbine blade for broadband active control, which comprises a blade body and a plurality of jet parts, the plurality of jet parts are arranged under the surface of the blade body, and the plurality of jet parts are along the upstream side of the air flow separation line on the surface of the blade body The surface of the blade body is provided with a plurality of jet outlets communicating with the jet ports of the jet component, which is a low Reynolds number plasma synthetic jet exciter. The invention drives the plasma synthetic jet exciter by high-frequency DC pulse power supply, generates a synthetic jet with a higher speed, controls the flow on the surface of the wind turbine blade, and overcomes the flow separation of the suction surface of the blade through the jet active control method, which can be more It has high aerodynamic performance in the range of large incoming flow angle of attack, reduces the working resistance and unsteady aerodynamic load of wind turbine blades, and improves the power generation efficiency and stability of wind turbines.

Description

Wind turbine blades for broadband active control

technical field

The invention belongs to the field of active control of wind turbine blades, in particular to a wind turbine blade for broadband active control.

Background technique

With the increasing energy crisis, many countries are developing renewable energy, wind energy is an important part of it, and the number of wind turbines in the world is huge. It is of great significance to study the aerodynamic characteristics of wind turbine blades to improve efficiency and stability.

When the common horizontal axis wind turbine is running, the working environment is complex, and the aerodynamic parameters of the incoming gas (speed, incoming flow angle of attack, etc.) change greatly. Steady separation leads to the dynamic stall phenomenon of the blades, which increases the unsteady aerodynamic load of the wind turbine, has a great impact on the aerodynamic performance and structural fatigue life of the wind turbine, and reduces the power generation efficiency and service life of the wind turbine.

At present, in the field of active control of wind turbine blades, the widely used air blowing control scheme, plasma actuator based on dielectric barrier discharge and piezoelectric thin film synthetic jet actuator to change the local or global flow field structure, effectively reduce the factors Aerodynamic losses due to flow separation. The insufflation air flow control solution in the prior art requires additional air sources, pipelines and control valves, thus resulting in increased extra weight and reduced system reliability due to complex structures. A wind turbine blade based on the dielectric barrier discharge plasma actuator improves the aerodynamic characteristics of the blade surface, but the structure of the dielectric barrier discharge plasma actuator determines that the blade surface must have a protruding structure, which obviously increases the surface resistance of the wind blade. Although this design makes the blade have more stable aerodynamic characteristics, it loses efficiency; a synthetic jet exciter that uses the repeated oscillation of the piezoelectric film to periodically blow air and convert the consumed electrical energy into fluid kinetic energy, thereby Improve the local or global flow field structure and reduce the aerodynamic loss, but its momentum output ability is weak, the control ability is not strong, and the response frequency is low.

Therefore, in the field of wind power generation, there is an urgent need for a blade with excellent active control ability, which should have the advantages of small additional weight, simple structure, stable operation, strong control ability, and wide operating frequency, so that the wind turbine blade can be used in complex working conditions. It has excellent aerodynamic characteristics and stability.

SUMMARY OF THE INVENTION

In view of this, the present invention aims to provide a wind turbine blade for broadband active control, which has a wider active control response frequency, has a strong control ability to improve the aerodynamic performance of the blade, and has a simple additional structure.

For achieving the above object, technical scheme of the present invention is as follows:

A wind turbine blade for broadband active control, comprising a blade body and a plurality of jet parts, a plurality of the jet parts are arranged below the surface of the blade body, and the plurality of the jet parts are along the upstream of the air flow separation line on the surface of the blade body It is arranged on the side, and is mainly arranged at the high lift section near the tip of the blade. On the surface of the blade body, there are a plurality of jet outlets that communicate with the jet ports of the jet components, and the jet components are low Reynolds number plasma synthetic jet excitation. device.

Further, each of the low Reynolds number plasma synthetic jet exciters includes a buffer cavity, a discharge cavity, an anode discharge electrode, a cathode discharge electrode and a heat-resistant silica gel, and the discharge cavity is arranged inside the buffer cavity, The discharge chamber is arranged at the bottom of the buffer chamber, and a plurality of low-speed jet ports are evenly opened on the upper wall of the buffer chamber. The low-speed jet ports are the jet ports of the exciter, and the lower wall of the discharge chamber penetrates the anode discharge electrode and the cathode discharge electrode, fixed and sealed with the heat-resistant silica gel, and a plurality of high-speed jet ports are evenly opened on the upper wall of the discharge chamber.

Further, each of the low Reynolds number plasma synthetic jet exciters includes a buffer cavity, a discharge cavity, an anode discharge electrode, a cathode discharge electrode and a heat-resistant silica gel, and the discharge cavity is fixed outside the buffer cavity, The discharge chamber is arranged at the bottom of the buffer chamber, and the anode discharge electrode and the cathode discharge electrode penetrate into the bottom wall of the discharge chamber, and are fixed and sealed with the heat-resistant silica gel. For the jet port, a through hole corresponding to the high-speed jet port is opened on the bottom wall of the buffer cavity, and the size of the through hole and the high-speed jet port are adapted. The low-speed jet port is the jet port of the exciter.

Further, the sum of the cross-sectional areas of all the low-speed jet ports is greater than the sum of the cross-sectional areas of all the high-speed jet ports.

Further, the jet outlet on the surface of the blade body matches the low-speed jet outlet of the exciter, and is a hole or a slit, specifically a straight hole, an oblique hole, a straight slit or an oblique slit.

Further, a buffer cavity is prefabricated on the inner surface of the blade body, the buffer cavity is made of the same material as the blade body, and the discharge cavity is assembled to the buffer cavity.

Further, a buffer cavity is formed by grinding the lower surface of the blade body, and the discharge cavity is assembled to the buffer cavity.

Further, an active control system for adjusting the discharge frequency of the exciter according to the real-time flow field aerodynamic characteristics of the wind turbine blade surface is installed on the blade body.

Further, the anode discharge electrode and the cathode discharge electrode are powered by a high-pulse power source, and the pulse power source is used to adjust the jet outflow intensity under different working conditions of the wind turbine.

Further, the cavity wall of the discharge cavity is made of insulating material, and a flow guiding structure is arranged in the buffer cavity.

Compared with the prior art, the wind turbine blade for broadband active control of the present invention has the following advantages:

1. The additional structure of the blade of the present invention is simple, the additional weight is small, and the response frequency range is wide. Compared with the blade without active control capability, the active control capability of the blade can reduce the unsteady aerodynamic load when the blade is working, so it has a longer life than ordinary wind turbine blades.

2. The local control ability of the blade surface is strong, the control effect is good, and the control is strengthened in the main parts of the wind turbine blade that generate lift. Due to the small geometric size of a single jet component and the characteristics of easy installation, multiple jet components are arranged in an array on the surface of the wind turbine blade. Local control effect.

3. The designed blade has a wide operating frequency range and has the real-time response capability of high-frequency control. The wind turbine can realize the adjustment method based on the incoming flow feedforward, and adjust the control pulse spectrum according to the surface of the wind turbine blade or the real-time flow field characteristics of the incoming flow. Compared with the traditional control method, a better active control effect can be obtained.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

1 is a schematic structural diagram of a wind turbine blade for broadband active control according to an embodiment of the present invention;

Fig. 2 is the structural representation of the jet component;

Figure 3 is a schematic diagram of the arrangement of the exciters with the buffer cavity being a cylinder and the low-speed jet port being a straight hole on the wind turbine blade;

FIG. 4 is a schematic diagram of the arrangement of the exciters on the wind turbine blade with the buffer cavity as a cuboid and the low-speed jet opening as a slit.

Description of reference numbers:

1-Low-speed jet port, 2-buffer chamber, 3-high-speed jet port, 4-discharge chamber, 5-anode discharge electrode, 6-blade body, 7-low Reynolds number plasma synthetic jet exciter, 8-cathode discharge electrode , 9-high lift section of the blade tip, 10-jet outlet.

Detailed ways

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict.

The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

As shown in Figures 1-2, a wide-band active control wind turbine blade includes a blade body 6 and a plurality of low Reynolds number plasma synthetic jet exciters 7, a plurality of said low Reynolds number plasma synthetic jets The exciter 7 is arranged under the surface of the blade body 6, and several of the low Reynolds number plasma synthetic jet exciters 7 are arranged along the upstream side of the air flow separation line on the surface of the blade body 6, and are mainly arranged in the high lift section 9 near the blade tip There, a plurality of jet outlets 10 communicated with the jet ports of the low Reynolds number plasma synthetic jet exciter 7 are opened on the surface of the blade body.

The specific structure of the low Reynolds number plasma synthetic jet exciter 7 is: including a buffer chamber 2, a discharge chamber 4, an anode discharge electrode 5, a cathode discharge electrode 8 and heat-resistant silica gel, and the discharge chamber 4 is arranged in the buffer chamber 2. Inside, the discharge chamber 4 is arranged at the bottom of the buffer chamber 2, and a plurality of low-speed jet ports 1 are evenly opened on the upper wall of the buffer chamber 2. The low-speed jet ports 1 are the jet ports of the exciter. The lower wall of the discharge chamber 4 penetrates the anode discharge electrode 5 and the cathode discharge electrode 8, and is fixed and sealed with the heat-resistant silica gel.

The specific structure of the low Reynolds number plasma synthetic jet exciter 7 can also be: including a buffer chamber 2, a discharge chamber 4, an anode discharge electrode 5, a cathode discharge electrode 8 and heat-resistant silica gel, and the discharge chamber 4 is fixed in the buffer chamber. Outside the cavity 2, the discharge cavity 4 is arranged at the bottom of the buffer cavity 2, and the anode discharge electrode 5 and the cathode discharge electrode 8 are penetrated into the bottom wall of the discharge cavity 4, and are fixed and sealed with the heat-resistant silica gel. The top wall of the cavity 4 is evenly provided with a plurality of high-speed jet ports 3, and the bottom wall of the buffer cavity 2 is provided with through holes corresponding to the high-speed jet ports 3 one-to-one, and the size of the through holes and the high-speed jet ports are adapted. A plurality of low-speed jet openings 1 are evenly opened on the top wall of the device, and the low-speed jet openings 1 are the jet openings of the exciter.

The sum of the cross-sectional areas of all the low-speed jet ports 1 is greater than the sum of the cross-sectional areas of all the high-speed jet ports 3 .

The jet outlet 10 on the surface of the blade body 6 is adapted to the low-speed jet outlet 1 of the buffer cavity, and is a hole or a slit, specifically a straight hole, an oblique hole, a straight slit or an oblique slit. The specific arrangement may be as follows: a plurality of arrays of holes or a slot are arranged on the upper wall of the buffer cavity 2, and the airfoil jet outlet 10 is adapted to it.

A buffer cavity 2 is prefabricated on the inner surface of the blade 6 , the buffer cavity 2 is made of the same material as the blade 6 , and the discharge cavity 4 is assembled into the buffer cavity 2 .

The buffer cavity 2 may also be formed by grinding the lower surface of the blade 6 , and the discharge cavity 4 is assembled into the buffer cavity 2 .

An active control system that adjusts the discharge frequency of the exciter according to the real-time flow field aerodynamic characteristics of the wind turbine blade surface is installed on the blade 6 .

The anode discharge electrode 5 and the cathode discharge electrode 8 are powered by a high-frequency pulse power supply, which is used to adjust the jet outflow intensity under different working conditions of the wind turbine.

The cavity wall of the discharge cavity 4 is made of insulating material, and a flow guiding structure is arranged in the buffer cavity 2 .

In order to make the control effect of the blade body 6 better, there must be a larger control area, and then a number of the exciters 7 need to be evenly arranged on the surface of the blade body 6 of the wind turbine, which can be single or multiple. The rows are arranged linearly. Since the lift of the wind turbine is mainly in the high-lift section 9 of the blade tip of the blade body 6, it is densely arranged at the high-lift section 9 of the blade tip.

The specific structures of the buffer cavity 2 and the discharge cavity 4 may be that the buffer cavity 2 and the discharge cavity 4 are both hollow cylinder structures, and the two are arranged coaxially; or the buffer cavity 2 may be a hollow cuboid structure, so The discharge chamber 4 is a hollow cylindrical structure, and the discharge chamber 4 is arranged facing the bottom of the buffer chamber 2 .

As shown in Figure 3 and Figure 4, the arrangement of jet components with two specific structures on the wind turbine blade is shown. Figure 3 shows that the buffer cavity is a cylinder and the low-speed jet port is a straight hole on the wind turbine blade. An arrangement; Figure 4 shows an arrangement on the wind turbine blade when the buffer cavity is a cuboid and the low-speed jet port is a slit.

The exit airflow velocity of the low Reynolds number plasma synthetic jet exciter 7 can be controlled in the order of tens of meters per second, which is very suitable for the control of airflow separation on the suction surface of the horizontal axis wind turbine blade.

By setting the upper cross-sectional area of the buffer cavity 2 to be larger than the lower cross-sectional area of the buffer cavity 2, more low-speed jet ports 1 are arranged to increase the actual control area of the exciter, and the structure for adjusting the outflow can also be increased. or components for better control.

The cavity wall of the discharge cavity 4 is made of insulating material. The size, shape and spacing of the anode discharge electrode 5 and the cathode discharge electrode 8 can be set according to specific use requirements. A recommended method is that the electrode shape is cylindrical, the diameter is 1mm, and the spacing is 3mm.

The design of the structure of the discharge cavity and the buffer cavity controls the outflow speed; the pulse power supply controls the operating frequency and amplitude of the exciter, and the two work together to determine the outlet state of the jet, so as to communicate with the external airflow on the blade surface of the wind turbine. Momentum exchange to achieve the effect of active control.

The working principle of the exciter on the blade is: the gas in the discharge chamber 4 is heated and ionized by the discharge of the anode discharge electrode 5 and the cathode discharge electrode 8, so that the gas in the discharge chamber 4 expands, and the gas is ejected from the high-speed jet port 3 to the Buffer chamber 2, in the buffer chamber 2, the pressure and temperature of the high-speed gas are reduced and decelerated into a low-speed gas by resistance, and then ejected from the low-speed jet port 1. The diameter and height of the buffer chamber 2 and the size of the low-speed jet port 1 determine the jet flow to wind power generation. The air velocity on the surface of the blade body 6 and the air flow from the jet to the surface of the wind turbine blade body 6 exchange momentum with the outside air to achieve an active control effect. After one discharge is over, the external gas enters the exciter through the low-speed jet port 1, so that the gas parameters inside the exciter are restored to those before the discharge, and one working cycle ends.

Based on the above theoretical description, under the action of the broadband control signal input, the broadband DC pulse power supply drives the low-Reynolds number plasma synthetic jet exciter 7 to generate a higher-speed synthetic jet, which flows against the airfoil. For control, the wind turbine blade for broadband active control of the present invention overcomes the flow separation of the suction surface of the blade through the active jet control method, and can have higher aerodynamic performance in a larger range of inflow angle of attack, reducing wind turbine blades. The working resistance and unsteady aerodynamic load of the wind turbine can improve the power generation efficiency and stability of the wind turbine, and prolong the life of the wind turbine.

The jet flow scheme of the blade can also be adapted to the low-frequency active control signal, or to the high-frequency excitation control signal based on the wind turbine's flow feedforward, with a large operating frequency range and strong flow control capability.

Different positions of the blades have different jet control requirements due to different flow states. Therefore, the structure design of the buffer cavity 2 of the jet component is different, specifically the cross-sectional area of the buffer cavity 2, the shape and size of the low-speed jet port, and the specific flow guide structure. Arrangement, these factors all affect the situation of the exciter jet, which affects the airflow of the blade, and actively controls the airflow around the blade.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (9)

1. A broadband is aerogenerator blade for active control which characterized in that: the plasma synthetic jet flow exciter comprises a blade body (6) and a plurality of jet flow components, wherein the plurality of jet flow components are arranged below the surface of the blade body (6), the plurality of jet flow components are arranged along the upstream side of an airflow separation line on the surface of the blade body (6) and are mainly arranged at a high lift section (9) close to a blade tip, a plurality of jet flow outlets (10) communicated with the jet flow ports of the jet flow components are formed in the surface of the blade body (6), and the jet flow components are low Reynolds number plasma synthetic jet flow exciters (7);

an active control system for adjusting the discharge frequency of the exciter according to the real-time flow field aerodynamic characteristics of the surface of the wind driven generator blade is arranged on the blade body (6);

the pulse power supply controls the working frequency and amplitude of the exciter;

under the action of broadband control signal input, a broadband direct current pulse power supply drives a low Reynolds number plasma synthetic jet exciter (7) to generate high-speed synthetic jet to control the flow of the airfoil.

2. The broadband active control wind turbine blade according to claim 1, wherein: every low reynolds number plasma synthesis efflux exciter (7) all include cushion chamber (2), discharge chamber (4), anode discharge electrode (5), cathode discharge electrode (8) and heat-resisting silica gel, discharge chamber (4) set up the inside of cushion chamber (2), discharge chamber (4) set up in cushion chamber (2) bottom, evenly seted up a plurality of low-speed jet ports (1) at the roof of cushion chamber (2), low-speed jet port (1) be the jet orifice of exciter, penetrate anode discharge electrode (5) and cathode discharge electrode (8) at the diapire of discharge chamber (4), and use heat-resisting silica gel is fixed and sealed, has evenly seted up a plurality of high-speed jet ports (3) at the roof of discharge chamber (4).

3. The broadband active control wind turbine blade according to claim 1, wherein: each low Reynolds number plasma synthetic jet exciter (7) comprises a buffer cavity (2), a discharge cavity (4), an anode discharge electrode (5), a cathode discharge electrode (8) and heat-resistant silica gel, the discharge cavity (4) is fixed outside the buffer cavity (2), the discharge cavity (4) is arranged at the bottom of the buffer cavity (2), an anode discharge electrode (5) and a cathode discharge electrode (8) penetrate through the bottom wall of the discharge cavity (4) and are fixed and sealed by the heat-resistant silica gel, a plurality of high-speed jet orifices (3) are uniformly arranged on the top wall of the discharge cavity (4), through holes which are in one-to-one correspondence with the high-speed jet orifices (3) are arranged on the bottom wall of the buffer cavity (2), the sizes of the through holes are adapted to the sizes of the high-speed jet orifices, a plurality of low-speed jet ports (1) are uniformly formed in the top wall of the buffer cavity (2), and the low-speed jet ports (1) are jet ports of the exciter.

4. The broadband active control wind turbine blade according to claim 2 or 3, wherein: the sum of the cross-sectional areas of all the low-speed jet ports (1) is larger than the sum of the cross-sectional areas of all the high-speed jet ports (3).

5. The broadband active control wind turbine blade according to claim 4, wherein: the jet flow outlet (10) on the surface of the blade body (6) is matched with the low-speed jet flow port (1) of the exciter and is a hole or a seam, in particular a straight hole, an inclined hole, a straight seam or an inclined seam.

6. The broadband active control wind turbine blade according to claim 5, wherein: at prefabricated cushion chamber (2) of blade body (6) internal surface, cushion chamber (2) are the same with blade body (6) material, assemble discharge chamber (4) to cushion chamber (2).

7. The broadband active control wind turbine blade according to claim 5, wherein: the lower surface of the blade body (6) is polished to form a buffer cavity (2), and the discharge cavity (4) is assembled to the buffer cavity (2).

8. The broadband active control wind turbine blade according to claim 7, wherein: the anode discharge electrode (5) and the cathode discharge electrode (8) are powered by a high-frequency pulse power supply, and the pulse power supply is used for adjusting the strength of the jet flow under different working conditions of the wind driven generator.

9. The broadband active control wind turbine blade according to claim 8, wherein: the cavity wall of the discharge cavity (4) is made of insulating materials, and a flow guide structure is arranged in the buffer cavity (2).

Images