Vertical axis wind turbine with front edge active telescopic sliding blade
阅读说明：本技术 一种带有前缘主动伸缩滑片的垂直轴风力机 (Vertical axis wind turbine with front edge active telescopic sliding blade ) 是由 倪露露 李春 缪维跑 向斌 于 2019-09-26 设计创作，主要内容包括：本发明提供了一种带有前缘主动伸缩滑片的垂直轴风力机,属于风力发电机领域。本发明提供的带有前缘主动伸缩滑片的垂直轴风力机具有多个翼型叶片,翼型叶片包括：开槽,设置在翼型叶片的上表面上；伸缩滑片,设置在开槽内；驱动装置,用于驱动伸缩滑片伸出开槽或缩回开槽；以及控制系统,用于检测所述翼型叶片的相位角状态并控制所述驱动装置。所以,本发明可以根据叶片运行的攻角控制滑片的伸出和收缩,达到在失速攻角时伸出提高翼型的气动性能,非失速攻角时缩回不影响原有的气动性能,相对于涡流发生器与格尼襟翼,伸缩滑片不会产生额外阻力,整个机构简单重量轻,耗能低,易操作,维护成本低。(The invention provides a vertical axis wind turbine with a front edge active telescopic sliding blade, and belongs to the field of wind driven generators. The invention provides a vertical axis wind turbine with a front edge active telescopic sliding blade, which is provided with a plurality of airfoil blades, wherein each airfoil blade comprises: the slot is arranged on the upper surface of the airfoil blade; the telescopic sliding sheet is arranged in the open slot; the driving device is used for driving the telescopic sliding sheet to extend out of the slot or retract into the slot; and the control system is used for detecting the phase angle state of the airfoil blade and controlling the driving device. Therefore, the extension and contraction of the sliding vane can be controlled according to the operating attack angle of the blade, the aerodynamic performance of the airfoil profile is improved by extending the sliding vane when the attack angle is stalled, the original aerodynamic performance is not affected by retracting the sliding vane when the attack angle is not stalled, compared with a vortex generator and a gurney flap, the telescopic sliding vane does not generate extra resistance, and the whole mechanism is simple, light in weight, low in energy consumption, easy to operate and low in maintenance cost.)
1. A vertical axis wind turbine with a leading edge active telescoping vane having a plurality of airfoil blades, the airfoil blades comprising:
a slot disposed on an upper surface of the airfoil blade;
the telescopic sliding sheet is arranged in the open slot;
the driving device is used for driving the telescopic sliding piece to extend out of the slot or retract into the slot; and
and the control system is used for monitoring the azimuth angle state of the airfoil blade and controlling the driving device.
2. The vertical axis wind turbine with leading edge active telescoping vanes as claimed in claim 1, wherein:
wherein, the horizontal distance between the slotted groove and the front edge of the airfoil blade is 5% -15% of the chord length of the airfoil.
3. The vertical axis wind turbine with leading edge active telescoping vanes as claimed in claim 1, wherein:
wherein the drive means is disposed inside the airfoil blade.
4. The vertical axis wind turbine with leading edge active telescoping vanes as claimed in claim 1, wherein:
when the telescopic sliding vane retracts into the slot, the top end of the telescopic sliding vane and the outer surface of the airfoil blade form a smooth curve.
5. The vertical axis wind turbine with leading edge active telescoping vanes as claimed in claim 1, wherein:
wherein the chord length direction of the airfoil blade parallel to the horizontal plane is taken as an X axis, the direction parallel to the horizontal plane and vertical to the chord length is taken as a Y axis, and the direction vertical to the horizontal plane and the chord length is taken as a Z axis,
when the telescopic sliding vane extends out of the slot, the height of the telescopic sliding vane on the Z axis is 2% -3% of the chord length of the airfoil blade, the thickness of the part of the telescopic sliding vane extending out of the slot along the X axis is 0.5% -0.6% of the chord length of the airfoil blade, and the length of the part of the telescopic sliding vane extending out of the slot along the Y axis is less than or equal to the width of the airfoil blade at the position of the slot along the Y axis.
6. The vertical axis wind turbine with leading edge active telescoping vanes as claimed in claim 1, wherein:
wherein the driving device includes:
the stepping motor is fixedly arranged on the airfoil blade;
the speed reduction gear is fixedly arranged on the airfoil blade and is driven by the stepping motor; and
and one end of the crank connecting rod is fixedly arranged on the reduction gear, and the other end of the crank connecting rod is fixedly connected with the telescopic sliding piece and moves along with the movement of the reduction gear, so that the telescopic sliding piece is driven to extend out of the open slot or retract back into the open slot.
7. The vertical axis wind turbine with leading edge active telescoping vanes of claim 6, wherein:
wherein the driving device further comprises:
and a supporting fixture for preventing the stepping motor from being displaced.
8. The vertical axis wind turbine with leading edge active telescoping vanes as claimed in claim 1, wherein:
wherein the control system comprises:
the angle sensor is used for monitoring the azimuth angle of the airfoil blade; and
a control unit for controlling the driving device,
when the angle sensor monitors that the airfoil blade rotates to an azimuth angle corresponding to a stall attack angle of an upwind area, a first control signal is generated and sent to the control unit, and the control unit controls the driving device to drive the telescopic sliding sheet to extend out of the slot and keep the extending height unchanged; when the airfoil blade is monitored to be at an azimuth angle corresponding to a non-stall attack angle, a second control signal is generated and sent to the control unit, and the control unit controls the driving device to drive the telescopic sliding vane to be completely retracted into the slot.
Technical Field
The invention relates to a vertical axis wind turbine, in particular to a vertical axis wind turbine with a front edge active telescopic sliding sheet, and belongs to the field of wind driven generators.
Background
In order to deal with the huge crisis of increased energy demand and exhaustion of fossil energy, the wind power generation technology is rapidly developed in the past decades as a new energy utilization mode. The wind driven generator can be divided into a horizontal axis wind turbine and a vertical axis wind turbine according to the relation between the rotating shaft of the wind wheel and the wind direction. Among them, the horizontal axis wind turbine is a major research object at present because of its advantages such as being suitable for large wind power plants and having a relatively high wind energy utilization coefficient. However, site selection suitable for building large wind farms is almost eliminated in the future, and therefore vertical axis wind turbines have received increasing attention due to their advantages of miniaturization and integration with buildings. Compared with a horizontal shaft wind turbine, the vertical shaft wind turbine has the advantages of no need of wind alignment, low noise, simple design, compactness, low installation and maintenance cost and the like. However, the wind energy utilization coefficient of the vertical axis wind turbine is low, and the dynamic stall phenomenon is easily caused by the large change of the attack angle of the blade in the operation process. The dynamic stall of the wind turbine blade not only can cause the lift and the resistance to be increased rapidly, but also can cause larger vortex-shaped disturbance, thereby greatly influencing the safe operation of the wind turbine structure.
The existing flow control technology for improving the stall attack angle and the aerodynamic performance of the wind turbine blade comprises the following steps: vortex generators, gurney flaps, inflatable leading edge technology, applied jets, and the like. Although researches have been carried out, the passive or active control technologies can effectively slow down or inhibit the dynamic stall, and improve the aerodynamic performance and the operation safety of the wind turbine. However, they have some defects which are difficult to overcome, such as that the passive control technology is easy to react under the small attack angle of the wing profile, and the aerodynamic performance of the wing profile is reduced; the active control technology is complex in control and transmission mechanism and requires large energy input.
Disclosure of Invention
The invention aims to solve the problem of aerodynamic performance of a wing profile, and provides a vertical axis wind turbine with a front edge active telescopic sliding blade.
The invention provides a vertical axis wind turbine with a front edge active telescopic sliding sheet, which is provided with a plurality of airfoil blades and is characterized in that the airfoil blades comprise: the slot is arranged on the upper surface of the airfoil blade; the telescopic sliding sheet is arranged in the open slot; the driving device is used for driving the telescopic sliding sheet to extend out of the slot or retract into the slot; and a control system for monitoring the state of the airfoil blade angle and controlling the drive means.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: wherein, the horizontal distance between the slot and the front edge of the airfoil blade is 5% -15% of the chord length of the airfoil.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: wherein the drive device is arranged inside the airfoil blade.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: when the telescopic sliding vane retracts to the groove, the top end of the telescopic sliding vane and the outer surface of the airfoil blade form a smooth curve.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: the chord length direction of the airfoil blade parallel to the horizontal plane is taken as an X axis, the direction parallel to the horizontal plane and perpendicular to the chord length is taken as a Y axis, the direction perpendicular to the horizontal plane and the chord length is taken as a Z axis, when the telescopic sliding sheet extends out of the slot, the height of the telescopic sliding sheet on the Z axis is 2% -3% of the chord length of the airfoil blade, the thickness of the part of the telescopic sliding sheet extending out of the slot along the X axis is 0.5% -0.6% of the chord length of the airfoil blade, and the length of the part of the telescopic sliding sheet extending out of the slot along the Y axis is less than or equal to the width of the airfoil blade at the.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: wherein, drive arrangement includes: the stepping motor is fixedly arranged on the airfoil blade; the speed reduction gear is fixedly arranged on the airfoil blade and is driven by the stepping motor; and one end of the crank connecting rod is fixedly arranged on the reduction gear, and the other end of the crank connecting rod is fixedly connected with the telescopic sliding piece and moves along with the movement of the reduction gear, so that the telescopic sliding piece is driven to extend out of the slot or retract into the slot.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: wherein, drive arrangement still includes: and a holding fixture for preventing the displacement of the stepping motor.
The vertical axis wind turbine with the front edge active telescopic sliding blade provided by the invention can also have the following characteristics: wherein, the control system includes: the angle sensor is used for monitoring the azimuth angle of the blade; the control unit is used for controlling the driving device, wherein when the angle sensor monitors that the airfoil blade rotates to an azimuth angle corresponding to a stall attack angle of an upwind area, a first control signal is generated and sent to the control unit, and the control unit controls the driving device to drive the telescopic sliding sheet to extend out of the slot and keep the extending height unchanged; and when the airfoil blade is monitored to be positioned at the azimuth angle corresponding to the non-stall attack angle, generating a second control signal and sending the second control signal to the control unit, wherein the control unit controls the driving device to drive the telescopic sliding blade to be completely retracted into the slot.
Action and Effect of the invention
According to the vertical axis wind turbine with the front edge active telescopic sliding vane, the controllable telescopic sliding vane is arranged at the front edge of the airfoil profile, so that the extension and the contraction of the sliding vane can be controlled according to the operating azimuth angle of the blade, the blade extends to the azimuth angle corresponding to the stall attack angle to improve the aerodynamic performance of the airfoil profile when operating, and the retraction does not influence the original aerodynamic performance when not operating at the stall attack angle. Compared with a vortex generator and a gurney flap, the telescopic sliding piece can not generate extra resistance, and the whole mechanism is simple, light in weight, low in energy consumption, easy to operate and low in maintenance cost.
Drawings
FIG. 1 is a schematic view of a telescoping vane and drive arrangement in a leading edge of an airfoil blade according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view of a airfoil blade of a vertical axis wind turbine with a leading edge active telescoping vane in an embodiment of the present invention;
FIG. 3 is a graph of tangential force variation at different phase angles for a vertical wind turbine using the original airfoil blade without the telescoping slide;
FIG. 4 is a schematic diagram showing the variation of the angle of attack with the phase angle and the variation of the height of the extension sliding blade extending out of the slot with the angle of attack at different tip speed ratios.
FIG. 5 is a graph of the vorticity in pitch for a pristine airfoil blade and an airfoil blade with a leading edge vane provided in accordance with an embodiment of the present invention.
Detailed Description
In order to make the technical means, the creation features, the achievement purposes and the effects of the invention easy to understand, the invention is specifically described below by combining the embodiment and the attached drawings.
In the following embodiments, chord length refers to the length of the airfoil blade leading edge to trailing edge line (i.e., chord line).
The angle of attack is the angle between the incoming flow and the chord line of the airfoil blade.
Tip speed ratio (λ) refers to the ratio of the linear velocity of the blade to the incoming wind speed.
< example >
FIG. 1 is a schematic structural diagram of a retractable blade and a driving device in a leading edge of an airfoil blade according to an embodiment of the present invention.
As shown in FIG. 1, the vertical axis wind turbine with the front edge active telescopic sliding vane comprises a plurality of
In the embodiment, the blade airfoil adopts a NACA0021 airfoil, and the maximum thickness is 21 percent of chord length.
FIG. 2 is a cross-sectional view of a airfoil blade of a vertical axis wind turbine with a leading edge active telescoping vane in an embodiment of the present invention.
In fig. 2, c is the chord length, u is the incoming flow velocity, and α is the angle of attack.
The chord length direction of the airfoil blade parallel to the horizontal plane is taken as an X axis, the direction parallel to the horizontal plane and vertical to the chord length is taken as a Y axis, and the direction vertical to the horizontal plane and the chord length is taken as a Z axis.
As shown in fig. 2, the
As shown in fig. 2, the telescopic sliding
FIG. 1 is a schematic structural diagram of a retractable blade and a driving device in a leading edge of an airfoil blade according to an embodiment of the present invention.
As shown in fig. 1, the
The whole driving device is fixedly arranged inside the
The supporting and
The stepping motor 7 is fixedly arranged inside the
The
One end of the
The control system consists of an angle sensor and a control unit.
The angle sensor is used for monitoring the azimuth angle of the airfoil blade.
The control unit is used for controlling the driving device.
When the angle sensor monitors that the airfoil blade rotates to an azimuth angle corresponding to a stall attack angle of an upwind area, a first control signal is generated and sent to the control unit, and the control unit controls the driving device to drive the telescopic sliding blade to extend out of the slot and keep the extending height unchanged; and when the airfoil blade is monitored to be positioned at the azimuth angle corresponding to the non-stall attack angle, generating a second control signal and sending the second control signal to the control unit, wherein the control unit controls the driving device to drive the telescopic sliding blade to be completely retracted into the slot. In the range from the blade to the leeward area, the telescopic sliding sheet is completely retracted into the slot, and the original aerodynamic performance of the wind turbine is not affected.
FIG. 3 is a graph of tangential force variation at different phase angles for a vertical wind turbine using the original airfoil blade without the telescoping slide.
As shown in FIG. 3, the vertical axis wind turbine blade mainly provides the torque in the windward region, and the torque provided by the blade in the leeward region is smaller. Therefore, the control system mainly detects the angle of attack of the blades in the windward region, and the sliders are kept in a retracted state inside the blades in the leeward region.
FIG. 4 is a schematic illustration of the variation of the angle of attack with tip ratio and the variation of the height of the telescoping slide extending out of the slot with angle of attack in an embodiment of the present invention.
As shown in fig. 4, the angle of attack of the blades varies in one revolution at different tip speed ratios. When the wind turbine rotates at a fixed rotating speed, the change curve of the attack angle of the blade along with the azimuth angle is also determined. When the angle sensor monitors that the airfoil blade rotates to an azimuth angle corresponding to a stall attack angle of an upwind area, a first control signal is generated and sent to the control unit, and the control unit controls the driving device to drive the telescopic sliding blade to extend out of the slot and keep the extending height unchanged; and when the airfoil blade is monitored to be positioned at the azimuth angle corresponding to the non-stall attack angle, generating a second control signal and sending the second control signal to the control unit, wherein the control unit controls the driving device to drive the telescopic sliding blade to be completely retracted into the slot. In the range from the blade to the leeward area, the telescopic sliding sheet is completely retracted into the slot, and the original aerodynamic performance of the wind turbine is not affected.
Specifically, as shown in fig. 4, fig. 4 illustrates the stall range of the blade and the variation of the vane with azimuth angle when λ ═ 2. In this embodiment, the telescopic sliding vane is kept in the slot under normal condition, and the original pneumatic performance of the blade is not affected. As the blade rotates, the angle of attack of the blade begins to increase, when the angle of attack of the blade increases to about 18 degrees, the corresponding azimuth angle of the blade is about 50 degrees, the front edge of the blade begins to generate separation vortex, at the moment, the stall azimuth angle is detected by the angle sensor, the control system controls the operation of the driving device, the telescopic sliding vane is driven to extend out of the surface of the blade and keep the maximum height of the sliding vane unchanged, the extending speed is related to the rotating speed of the wind turbine and the incoming flow wind speed, and the time taken for the sliding vane to extend to the maximum height in the example is the time of about 10 degrees of azimuth. Until the blade rotates to about 18 degrees of attack angle again, when the azimuth angle of the blade is about 170 degrees, the dynamic stall phenomenon disappears, at this time, the azimuth angle is detected by the angle sensor, the control system controls the operation of the driving device to drive the telescopic sliding blade to retract into the blade, and the retraction speed is the same as the extension speed. The blade rotates to a leeward area of 180-360 degrees, the suction surface and the pressure surface of the blade are exchanged, and the sliding blade is retracted into the blade slot in the azimuth angle range, so that the original pneumatic performance of the wind turbine is not influenced.
FIG. 5 is a graph of the vorticity in pitch for a pristine airfoil blade and an airfoil blade with a leading edge vane provided in accordance with an embodiment of the present invention.
As shown in fig. 5, when the pitch up angle of attack reaches 22.45 °, the original airfoil leading edge generates significant separation vortices, and the separation vortices have developed from the leading edge to the trailing edge and start to shed from the airfoil surface, flow separation occurs, leading to a sharp drop in the airfoil lift coefficient, while the airfoil leading edge with the telescopic sliding vane still maintains a good attached flow, and separation vortices occur only at the trailing edge. When the wing blocking type tilts up to 25 degrees, the control effect of the telescopic sliding vane is further displayed, the generation and the falling of separation vortex are inhibited, and the stall characteristic of the wing type is improved.
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