CN102364098A - A kind of wind power generating set and its blade - Google Patents

Abstract

The invention discloses a blade for a wind generating set. The blade is a shell (3) in which a hollow cavity is formed. The blade comprises a pneumatic surface (32) and a pressure surface (31) opposite to the pneumatic surface (32), and is characterized by also comprising a channel (4) passing through the pneumatic surface (32), and an air extractor (2) arranged in the channel (4), wherein the air inlet of the channel (4) is positioned outside the shell (3) and the air outlet of the channel (4) is positioned in the hollow cavity of the shell; and the air extractor (2) is arranged on one side, close to the air outlet, of the channel (4). During work of the blade, a separation phenomenon of boundary layers is delayed or avoided; the lift drag ratio of the surface of the blade is increased effectively; and the working efficiency of a fan is improved. The invention also provides a wind generating set comprising the blade.

Description

A kind of wind power generating set and its blade

technical field

The invention relates to the technical field of wind power generating equipment, in particular to a blade for a wind power generating set. The invention also relates to a wind power generator comprising the blade described above.

Background technique

With the outbreak of energy crisis worldwide, wind power and other renewable energy sources have been more and more widely used, thus driving the development of wind power generation systems.

A wind turbine is a mechanical device that converts wind resources into electrical energy. The device required for wind power generation is called a wind turbine (hereinafter referred to as a fan), and a fan generally includes three parts: a wind wheel, a generator and a tower; The wheel mainly includes a hub and blades. When the wind blows to the blades, aerodynamic force is generated on the blades to drive the wind wheel to rotate.

Please refer to FIG. 1 , which is a diagram of a surface flow field of a typical blade surface when the boundary layer is separated.

The flow direction of the airflow is the direction from the leading edge to the trailing edge of the blade. The side of the blade 1 with a higher airflow velocity and a lower pressure is the aerodynamic surface 12, and the side with a lower airflow velocity and higher pressure is the pressure surface. It faces away from the aerodynamic surface 12 . The cross-section formed by cutting the blade transversely is called the airfoil, and the airflow flows from the leading edge to the trailing edge of the airfoil, and the variable-section blade has multiple airfoils. On the same airfoil of the blade 1, the airflow velocity of the aerodynamic surface 12 is greater than that of the pressure surface 11. According to Bernoulli's principle, the pressure of the pressure surface 11 is greater than that of the aerodynamic surface 12, and the total pressure direction is from the pressure surface 11 to the aerodynamic surface. 12. To form a lift force, the force formed by the obstruction of the airfoil to the gas flow is the resistance of the airfoil.

As shown in Figure 1, the process of airflow flowing from the leading edge to the trailing edge on the aerodynamic surface generally includes an acceleration phase and a deceleration phase. In the acceleration stage of the airflow, due to the shape change of the airfoil, the airflow is squeezed, so that the speed of the airflow in the acceleration stage increases, and the forward (the forward direction in the text refers to the direction from the leading edge to the trailing edge) pressure gradually decreases; in the airflow In the acceleration stage of the airflow, the forward pressure of the airflow is greater than its reverse (reverse in the text refers to the direction from the trailing edge to the leading edge) pressure, the total pressure direction is towards the trailing edge, and the airflow can flow forward. When the forward pressure drops to the minimum value, the reverse pressure is greater than the forward pressure, the total pressure direction is towards the leading edge, the forward flow velocity of the airflow decreases, and the airflow enters the deceleration stage. In the deceleration stage, the forward pressure of the airflow is still decreasing, and the forward velocity is gradually reduced. When the forward velocity of the airflow drops to the point where its kinetic energy is not enough to maintain the forward flow of the airflow, the airflow appears countercurrent at the position of the boundary layer. The countercurrent will push the boundary layer upwards, causing the boundary layer to separate from the airfoil surface, resulting in boundary layer separation.

Boundary layer separation will generate fluid backflow at the separation point, which intensifies the collision friction between fluids and between fluid and airfoil, thereby increasing the resistance of the airfoil and greatly reducing the lift of the airfoil, resulting in the ratio of lift and drag on the surface of blade 1 (ie the lift-to-drag ratio) is greatly reduced, which affects the rotation of the blade 1, and then seriously affects the working efficiency of the fan.

In the actual working process of the fan, the inflow position of the airflow on the airfoil is generally changed by adjusting the pitch and yaw system of the wind turbine, thereby changing the angle between the inflow direction of the airflow and the chord line of the airfoil (that is, the angle of attack). , thereby increasing the positive component of the pressure and the positive component of the velocity in order to delay or eliminate the boundary layer separation of the blade. However, the wind speed and direction in the wind farm change quickly and are uncontrollable. There are many heavy moving parts in the yaw and pitch system of the wind turbine. Frequent use of the yaw and pitch system will increase the wear of the fan and affect the wind turbine. At the same time, if the system responds too fast, it will easily cause fatigue damage to the yaw and pitch system and increase the wear and tear of the fan. However, if the system responds too slowly, it will not be able to respond to the upcoming boundary layer separation phenomenon in time, thus affecting Utilization of wind energy by wind turbines.

Therefore, under the condition of avoiding frequent use of yaw and pitch systems, how to realize the timely response of wind turbines to the upcoming boundary layer separation phenomenon, and delay or avoid the occurrence of boundary layer separation phenomenon when the wind conditions change, Just become the problem that those skilled in the art need to solve urgently.

Contents of the invention

The object of the present invention is to provide a blade for a wind power generating set, which is provided with a channel communicating through the aerodynamic surface, and the air outlet of the channel is located in the cavity, and an air extraction device is arranged at the air outlet. When the pressure of the air on the surface drops, the air extraction device starts to pump the stagnant airflow on the aerodynamic surface into the cavity, and the subsequent high-pressure airflow can be replenished in time, thereby delaying or avoiding the occurrence of boundary layer separation, effectively The lift-to-drag ratio of the blade surface is greatly improved, thereby improving the working efficiency of the fan. Another object of the present invention is to provide a wind power generating set comprising the above-mentioned blade.

In order to solve the above technical problems, the present invention provides a blade for a wind power generator set, which is a shell with a cavity inside, the blade includes an aerodynamic surface and a pressure surface opposite to the aerodynamic surface, and also includes a The channel of the aerodynamic surface, and the air extraction device installed in the channel; the air inlet of the channel is located outside the housing, and the air outlet is located in the cavity of the housing, and the air extraction device is installed on the side of the channel close to the air outlet.

Preferably, the air inlet is arranged at the end of the air inlet section of the passage, and the included angle between the axial direction of the air inlet section and the tangential direction of the aerodynamic surface at the air inlet point is greater than or equal to 0 °, and less than 90°.

Preferably, the axial direction of the air intake section is tangent to the aerodynamic surface at the air intake point.

Preferably, there are multiple channels, and each channel is independent of each other.

Preferably, each of the passages communicates in the radial direction of the blade.

Preferably, each of the passages is opened at the tip portion of the blade.

Preferably, a control device is also included, and the control device controls the opening or closing of the suction device according to a predetermined strategy.

Preferably, the control device includes a detection element and a control element;

The predetermined strategy is: the detection element detects the operating parameters of the wind power generating set, and transmits the operating parameters to the control element; the control element compares the received operating parameters with the predetermined parameters, and when receiving When the operating parameter of the control unit matches the predetermined parameter, the air pumping device is controlled to open.

Preferably, a pipe is opened in the cavity, one end of the pipe communicates with the air outlet, and the other end of the pipe is located at the pitch system of the wind power generating set.

The present invention also provides a wind power generating set, which includes a tower, a wind rotor and blades installed on the wind rotor, and the blades are the blades as described above.

The blade of the wind power generating set provided by the present invention is a shell with a cavity inside, and the blade includes an aerodynamic surface and a pressure surface, wherein the pressure on the aerodynamic surface is lower than the pressure on the pressure surface, and the pressure surface is opposite to the aerodynamic surface; The blade also includes a channel and an air extraction device, wherein the channel passes through the aerodynamic surface, the air extraction device is installed in the channel, the air inlet of the channel is located outside the casing, and communicates with the atmosphere, and the air outlet of the channel is located in the cavity of the housing , The air extraction device is installed on the side of the channel close to the air outlet.

When the airflow pressure at the air inlet of the channel on the aerodynamic surface drops to the limit value, start the air extraction device to suck the gas with lower pressure on the aerodynamic surface into the cavity of the blade through the channel, so that the subsequent airflow with higher pressure can be released in time. Supplemented, thereby delaying or avoiding the occurrence of boundary layer separation, effectively improving the lift-to-drag ratio of the blade surface, thereby improving the working efficiency of the fan.

In a specific embodiment, the number of passages provided by the present invention can be multiple, and each passage is opened on a plurality of airfoils; due to changes in wind conditions, the position where the boundary layer separation is likely to occur on the blade Changes will occur, setting multiple passages 4 can adapt to various wind conditions and expand the scope of application of the blade.

In another specific embodiment, the cavity of the blade provided by the present invention may be provided with a pipeline, one end of the pipeline communicates with the air outlet of the channel, and the other end is located at the pitch system of the wind power generating set; thus, through The air extracted by the air extraction device can enter the pitch system of the fan through the pipes arranged in the cavity, as the cooling medium of the pitch system, and discharge into the atmosphere after cooling the pitch motor and other equipment, thereby improving the airflow efficiency. utilization rate.

Description of drawings

Fig. 1 is a surface flow field diagram when a typical blade surface boundary layer is separated;

Fig. 2 is the surface flow field diagram of the blade provided by the present invention;

Fig. 3 is a perspective view of a specific embodiment of the blade provided by the present invention;

Fig. 4 is a sectional view of the blade shown in Fig. 3;

Fig. 5 is a principle diagram of a specific embodiment of the control device provided by the present invention.

Detailed ways

The core of the present invention is to provide a blade for a wind power generating set, the blade is opened with a passage through the aerodynamic surface, and the air outlet of the passage is located in the cavity, and an air extraction device is arranged at the air outlet. When the pressure of the air on the surface drops, the air extraction device starts to pump the stagnant airflow on the aerodynamic surface into the cavity, and the subsequent high-pressure airflow can be replenished in time, thereby delaying or avoiding the occurrence of boundary layer separation, effectively The lift-to-drag ratio of the blade surface is greatly improved, thereby improving the working efficiency of the fan. Another core of the present invention is to provide a wind power generating set including the above-mentioned blade.

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Fig. 2, Fig. 3 and Fig. 4; Fig. 2 is a surface flow field diagram of the blade provided by the present invention; Fig. 3 is a perspective view of a specific embodiment of the blade provided by the present invention; Fig. 4 is shown in Fig. 3 Cutaway view of the blade.

The blade provided by the present invention is used for a wind power generating set, which includes a nacelle, a tower supporting the nacelle, and blades installed on the nacelle, and the number of blades can be one, two, or three or more The blades are evenly installed on the blade hub in the circumferential direction and can move with the wind. The number of blades should be determined according to the actual working conditions and power generation requirements, and there is no limitation here. The blade provided by the present invention is a housing 3 with a cavity inside. The blade includes an aerodynamic surface 32 with a relatively high surface air velocity and a low pressure, and a pressure surface 31 with a relatively low surface air velocity and a relatively high pressure. The pressure surface 31 and In contrast to the aerodynamic surface 32, both the aerodynamic surface 32 and the pressure surface 31 are formed by the outer surface of the casing 3; the blade also includes a channel 4 and an air extraction device 2, wherein the channel 4 passes through the aerodynamic surface 32, and the air extraction device 2 is installed on the channel 4, the air inlet of the channel 4 is located outside the housing 3, and its air outlet is located in the cavity of the housing 3, and the air extraction device 2 is installed on the side of the channel 4 close to the air outlet.

The material of the shell 3 can be various metal materials or composite materials conventionally used in this field. The blades are under the action of strong wind for a long time and in the field working environment. Therefore, the material of the shell 3 needs to have strong wear resistance. performance and corrosion resistance.

The arrangement form of the air inlet of the passage 4 can meet the requirement that the angle between the air intake direction and the tangential direction of the aerodynamic surface 32 at the air intake point is greater than or equal to 0° and less than 90°. Structurally speaking, the air intake The port is the end of the air intake section, and the angle between the axis direction of the air intake section and the tangential direction at the air intake point is greater than or equal to 0° and less than 90°, so as to ensure that more airflow enters the channel 4 .

Preferably, the angle between the air intake direction of the channel 4 and the tangent direction of the aerodynamic surface 32 at the air intake point is equal to 0°, that is, the air intake direction is tangent to the aerodynamic surface 32, and the axial direction of the air intake section is in line with the aerodynamic surface 32. face tangent. In this way, the air flow enters the channel 4 more conveniently, and the energy loss of the air flow is reduced.

The air intake direction of the channel 4 is not limited to be tangent to the aerodynamic surface 32. Theoretically, as long as the passage of the air flow can be realized and the air flow can be ensured to enter the channel 4 smoothly, for example, the air intake direction of the air inlet can also be The tangent to the aerodynamic surface 32 has an appropriate leading edge angle.

The air intake point mentioned herein refers to the intersection of the axis of the airflow and the aerodynamic surface 32 .

It should be noted that the leading edge mentioned herein refers to the side of the airfoil on which the airflow flows in, and the trailing edge refers to the side of the airfoil on which the airflow flows out. The leading edge angle mentioned in this article refers to the angle between the airflow direction and the corresponding tangent to the airfoil surface in the direction towards the leading edge.

The above-mentioned air inlet can be opened on the aerodynamic surface 32, that is, the air inlet is directly opened on the housing 3 forming the aerodynamic surface 32; like this, there is no need to set up additional parts to install the air inlet on the aerodynamic surface 32, thereby simplifying the process. The opening process of channel 4.

The air inlet is not limited to being directly set on the aerodynamic surface 32, and it is also possible to only provide a connecting hole on the aerodynamic surface 32, and to set a connecting pipe in addition so that the outlet of the connecting pipe forms the above-mentioned air inlet.

Can be provided with pipeline 5 in the cavity of above-mentioned blade, and one end of pipeline 5 is communicated with described air outlet, and its other end is positioned at the pitch-changing system of described wind power generating set; It enters the pitch system of the fan through the pipe 5 arranged in the cavity, serves as the cooling medium of the pitch system, and discharges into the atmosphere after cooling the pitch motor and other equipment, thereby improving the utilization rate of the airflow and saving energy.

When the airflow pressure at the air inlet of the channel 4 on the aerodynamic surface 32 drops to the limit value, start the suction device 2, and the gas with a lower pressure on the aerodynamic surface 32 will be sucked into the cavity of the blade through the channel 4, so that the subsequent The high-pressure airflow can be replenished in time, thereby delaying or avoiding the occurrence of boundary layer separation, effectively improving the lift-to-drag ratio of the blade surface, and thus improving the working efficiency of the fan.

Further improvements can also be made to the blades of the wind power generating set provided by the present invention.

Please continue to refer to Fig. 3 and Fig. 4; in a specific embodiment, the number of channels 4 provided by the present invention can be multiple, and each channel 4 is respectively opened on a plurality of airfoils of the blade; As the conditions change, the position where the boundary layer separation is likely to occur on the blade will change. Setting multiple channels 4 can adapt to various wind conditions and expand the scope of application of the blade.

The number of channels 4 can be flexibly determined according to usage conditions, and the specific number is not limited here.

A plurality of passages 4 can also be provided on the same airfoil, these passages 4 are arranged along the chord line direction of the airfoil, and the passages 4 are independent, not connected to each other, and not interfered with each other.

The passages 4 on different airfoils can be independent of each other, or these passages 4 can be connected to each other along the radial direction of the blade, that is, a plurality of hole-shaped passages 4 on different airfoils can be connected to form A long slit, so that there is no need to make holes on each airfoil during processing, but only a long slit on the blade, which reduces the difficulty of processing.

Boundary layer separation is more likely to occur at the tip of the blade, therefore, each channel 4 can be opened in the part of the blade near the tip; or part of the channels 4 can be opened in the tip of the blade.

On the basis of the above specific embodiments, further improvements can be made to the blades of the wind power generating set provided by the present invention.

On the basis of the specific embodiments described above, further improvements can be made to the blade provided by the present invention.

Please refer to FIG. 5 , which is a schematic diagram of a specific embodiment of the control device provided by the present invention.

In another specific embodiment, the blade provided by the present invention also includes a control device, which controls the opening or closing of the air extraction device 2 according to a predetermined strategy, so that the air extraction device 2 can be realized by automatic control. The opening or closing of the air extraction device 2 does not need to be manually controlled, which reduces the labor intensity of the staff and improves the control accuracy of the air extraction device 2 .

Apparently, the opening or closing of the suction device 2 is not limited to automatic control by the control device, and can also be manually controlled.

The above control system includes a detection element 61 and a control element 62; the predetermined strategy is: the detection element 61 detects the operating parameters of the wind power generating set, and transmits the operating parameters to the control element 62; the control element 62 The received operating parameters are compared with predetermined parameters, and when the received operating parameters match the predetermined parameters, the air pumping device 2 is controlled to be turned on. The control signal of the control device comes from the operating parameters of the fan, such as: wind speed, pitch angle, wind rotor speed and so on. Through calculation or computer simulation, the relationship between boundary layer separation and fan operating parameters such as incoming wind speed, pitch angle and rotor speed is obtained. The controller is programmed based on the relationship between these parameters to control the relationship between the opening of the air extraction device 2 and the separation of the boundary layer, so as to achieve the purpose of actively controlling the separation of the boundary layer.

During the normal operation of the fan, the operation of the fan will enter the "boundary layer separation" state due to changes in the external working conditions. It can be determined whether the blade has entered the "boundary layer separation" state through the calculation of the operating parameters of the fan. When the detection equipment on the fan detects the current operating parameters of the fan and calculates that the fan has entered the state of "boundary layer separation", the boundary layer control system of the airflow channel 4 is activated. The air extraction device 2 installed on the air flow channel 4 is turned on, so that the air with a lower pressure on the aerodynamic surface 32 flows from the aerodynamic surface 32 to the channel 4 under the action of the air extraction device 2, so that the subsequent high-pressure air flow can be replenished in time. Thereby delaying or eliminating boundary layer separation.

In addition to the above-mentioned blades, the present invention also provides a wind power generating set including the above-mentioned blades. For the structure of other parts of the wind power generating set, please refer to the prior art, which will not be repeated here.

The wind power generating set and its blades provided by the present invention have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (10)

1. A blade for a wind power generating set, which is a housing (3) with a cavity in it, and the blade includes an aerodynamic surface (32) and a pressure surface (31) opposite to the aerodynamic surface (32), It is characterized in that it also includes a channel (4) passing through the aerodynamic surface (32), and an air extraction device (2) installed in the channel (4); the air inlet of the channel (4) is located at Outside the housing (3), its air outlet is located in the cavity of the housing, and the air extraction device (2) is installed on the side of the channel (4) close to the air outlet. 2. The blade for wind power generating set according to claim 1, characterized in that, the air inlet is arranged at the end of the air inlet section of the passage, and the axial direction of the air inlet section is in line with the aerodynamic The included angle of the leading edge in the tangential direction of the surface (32) at the air intake point is greater than or equal to 0° and less than 90°. 3. The blade for a wind power generating set according to claim 2, characterized in that, the axial direction of the inlet section is tangent to the aerodynamic surface (32) at the inlet point. 4. The blade for a wind power generating set according to any one of claims 1 to 3, characterized in that there are multiple channels (4), and each channel (4) is independent of each other. 5. The blade for a wind power generating set according to claim 4, characterized in that, each of the passages (4) communicates in the radial direction of the blade. 6. The blade for a wind power generating set according to claim 5, characterized in that, each of the passages (4) is opened at the blade tip of the blade. 7. The blade for a wind power generating set according to any one of claims 1 to 3, further comprising a control device, the control device controls the opening or closing of the air extraction device (2) according to a predetermined strategy. closure. 8. The blade for wind power generating set according to claim 7, characterized in that, the control device comprises a detection element (61) and a control element (62); The predetermined strategy is: the detection element (61) detects the operating parameters of the wind power generating set, and transmits the operating parameters to the control element (62); the control element (62) transmits the received operating parameters Compared with a predetermined parameter, the air extraction device (2) is controlled to be turned on when the received operating parameter matches the predetermined parameter. 9. The blade for a wind power generating set according to any one of claims 1 to 3, characterized in that, a pipe (5) is opened in the cavity, and one end of the pipe (5) is connected to the outlet The air port is connected, and the other end is located at the pitch control system of the wind power generating set. 10. A wind power generating set, comprising a tower, a wind rotor and blades installed on the wind rotor, characterized in that the blades are the blades according to any one of claims 1-9.

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