A vertical-axis wind turbine blade with deformable leading edge and a vertical-axis wind turbine

Abstract

The present invention discloses a vertical axis wind turbine blade with a deformable leading edge and a vertical wind turbine, and relates to a blade suitable for a vertical axis wind turbine, comprising a symmetrical blade body, airbag structures are installed on both sides of the leading edge of the blade body, and the two airbag structures are symmetrically arranged; one side of the airbag structure is connected with the side of the blade body, and the other side of the airbag structure is streamlined with the leading edge of the blade body; an air supply system for supplying air to the two airbag structures is also installed inside the blade body; the air supply system is controlled by the measurement results of the angle of attack sensor to achieve the purpose of dynamic control of the blade shape. The present invention overcomes the disadvantage of low lift coefficient of conventional symmetrical airfoils, improves the lift and dynamic stall angle of attack of the blade during the entire rotation cycle, and is conducive to the blade capturing more wind energy and improving output power.

Description

Technical Field

[0001] The present invention relates to the technical field of vertical axis wind turbines, and in particular to a vertical axis wind turbine blade with a deformable leading edge and a vertical axis wind turbine. Background Art

[0002] Vertical axis wind turbines appeared relatively late on the market. Although in theory they have the same efficiency as horizontal axis wind turbines, they have become a research hotspot today due to their advantages such as low requirements on wind direction, good generator maintenance and low noise.

[0003] When the vertical axis wind turbine is in operation, the blade angle of attack of the vertical axis wind turbine presents unsteady periodic changes, so that the blade angle of attack may change alternately within a range close to ±90°, which not only affects the aerodynamic performance of the vertical axis wind turbine, but also seriously affects the lift of the blades. Conventional blades with high lift and curvature are difficult to perform effectively. Therefore, the blades of vertical axis wind turbines generally adopt symmetrical airfoils. At the same time, due to the rapid change of the blade angle of attack, the flow around the blade will produce the so-called "dynamic stall" phenomenon, so that the periodic change of the blade angle of attack causes unsteady flow and nonlinear hysteresis of the aerodynamic force. The dynamic stall will also cause structural vibration, reduce the efficiency of the wind turbine, and cause additional noise.

[0004] To overcome the above problems, existing vertical axis wind turbines are equipped with pitch-changing mechanisms to keep the blade angle of attack within a certain range. However, when the size of the vertical axis wind turbine increases to a certain extent, the free flow conditions change significantly along the blade span, and it is difficult to maintain an optimal angle at this time. On the other hand, since the blades of the vertical axis wind turbine have a large inertia when in operation, it poses a great challenge to the reaction speed and load of the pitch-changing system. Therefore, there is an urgent need for a wind turbine blade that can significantly improve the aerodynamic performance of the blade through active flow control, thereby suppressing the dynamic stall phenomenon, improving the efficiency of the vertical axis wind turbine, and improving the operation quality of the wind turbine. Summary of the invention

[0005] In view of the serious dynamic stall phenomenon faced by vertical axis wind turbines and the insignificant aerodynamic efficiency of blades, the present invention provides a vertical axis wind turbine blade with a deformable leading edge, which improves the flow quality near the leading edge by actively changing the shape of the blade, thereby improving the wind turbine's ability to capture wind, reducing the wind turbine's structural vibration, and suppressing noise.

[0006] In order to achieve the purpose of the present invention, the technical solution adopted is: a vertical axis wind turbine blade with a deformable leading edge, including a symmetrical blade body, airbag structures are installed on both sides of the leading edge of the blade body, and the two airbag structures are symmetrically arranged; one side of the airbag structure is connected with the side of the blade body, and the other side of the airbag structure is streamlined with the leading edge of the blade body; an air supply system for supplying air to the two airbag structures is also installed inside the blade body.

[0007] Furthermore, the airbag structure includes an inflatable bag located at the leading edge of the blade body; a deformable rectifying structure is connected between the inflatable bag and the maximum thickness of the blade body.

[0008] Furthermore, the angle between the protruding direction of the inflatable bag and the central symmetry line of the blade body is 15° to 60°.

[0009] Furthermore, the rectification structure is a flexible diaphragm, and the rectification structure, the air-filled bag and the blade body together form a closed space, and the blade body is also provided with a through hole communicating with the closed space.

[0010] Furthermore, the air supply system includes an air pump fixedly installed in the blade body, and ventilation pipelines are connected between the outlet of the air pump and the two inflatable bags.

[0011] Furthermore, the air pump is a three-phase air pump.

[0012] Furthermore, a switch valve is installed on the ventilation pipeline.

[0013] A vertical axis wind turbine comprises the above blades, a rotating shaft and a bracket mounted on the rotating shaft, the blades are mounted on the bracket, and an angle of attack sensor is also embedded on the bracket.

[0014] Furthermore, a power supply and a controller are installed in the rotating shaft, the input end of the controller is electrically connected to the output end of the angle of attack sensor, and the output end of the controller is electrically connected to the air supply system.

[0015] The beneficial effects of the present invention are:

[0016] 1. By installing two airbag structures at the leading edge of the blade body, the blade shape can be actively changed according to the blade position and wind flow conditions when the blade rotates around the center, overcoming the disadvantage of low lift coefficient of conventional symmetrical airfoils, and improving the lift of the blade during the entire rotation cycle, which is conducive to the blade capturing more wind energy and increasing output power.

[0017] 2. By adjusting the two airbag structures, the curvature at the leading edge of the blade is dynamically changed, the stall angle of the blade is increased, and the maximum lift coefficient of the blade is increased, which is beneficial to improving the efficiency of the vertical axis force fan.

[0018] 3. Due to the dynamic change of the curvature at the leading edge of the blade, the dynamic stall phenomenon is slowed down, the structural vibration and noise are reduced, which is beneficial to improving the stability and safety of wind turbine operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of a vertical-axis wind turbine blade with a deformable leading edge provided by the present invention;

[0020] Figure 2 This is a schematic diagram of the operation of vertical axis wind turbine blades

[0021] Figure 3 It is a schematic diagram of the operation of an existing vertical axis wind turbine;

[0022] Figure 4 It is a schematic diagram of aerodynamic analysis of a vertical axis wind turbine blade with a deformable leading edge provided by the present invention;

[0023] Figure 5 It is a schematic diagram of the operation of a vertical-axis wind turbine blade with a deformable leading edge provided by the present invention.

[0024] Markings and corresponding parts names in the attached drawings:

[0025] 1. Blade body, 2. Airbag structure, 3. Air supply system, 4. Blade bracket, 5. Angle of attack sensor, 6. Fan rotating shaft;

[0026] 21. Inflatable bag, 22. Rectification structure;

[0027] 31. Air pump, 32. Ventilation pipe. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through specific implementation examples in conjunction with the accompanying drawings.

[0029] like Figure 1 As shown, the present invention provides a vertical axis wind turbine blade with a deformable leading edge, comprising a symmetrical blade body 1, airbag structures 2 are installed on both sides of the leading edge of the blade body 1, and the two airbag structures 2 are symmetrically arranged; one side of the airbag structure 2 is connected with the side streamline of the blade body 1, and the other side of the airbag structure 2 is connected with the leading edge of the blade body 1; an air supply system 3 for supplying air to the two airbag structures 2 is also installed inside the blade body 1.

[0030] The two sides of the blade body 1 refer to the side of the blade away from the vertical axis wind turbine rotation axis 6 and the side of the blade close to the vertical axis wind turbine rotation axis 6, and the two sides of the blade body 1 are symmetrical along the center of the blade body 1, so that the outer wall of the blade body 1 has a symmetrical structure.

[0031] When the two airbag structures 2 are inflated at the same time, the front end of the blade has a V-shaped groove, and the distance between the two side surfaces of the blade gradually decreases from the leading edge of the blade to the trailing edge of the blade, so that the two side surfaces of the blade remain streamlined. When one of the airbag structures 2 is inflated and the other airbag structure 2 is not inflated, the uninflated airbag structure 2 is attached to the blade body 1, so that the surface of the blade body 1 close to the uninflated airbag structure 2 maintains the original streamline; and one side of the inflated airbag structure 2 is tangent to the leading edge of the blade body 1, and the other side of the inflated airbag structure 2 is tangent to the side of the blade body 1, so that the blade body 1 close to the inflated airbag structure 2 can also maintain a streamlined shape, and finally the leading edge of the blade body 1 is tilted while the blade surface remains streamlined.

[0032] The interior of the blade body 1 is a hollow structure, and a ventilation gap is provided at the trailing edge of the blade body 1, so that outside air can enter the interior of the blade body 1 through the ventilation gap, thereby enabling the air supply system 3 to supply air to the two airbag structures 2; when there is no ventilation gap at the trailing edge of the blade body 1, an air intake pipe can be directly connected to the air inlet of the air supply system 3, and the outlet end of the air intake pipe can be extended to the trailing edge of the blade body 1, and the outlet end of the air intake pipe can be flush with the outer surface of the blade body 1.

[0033] The airbag structure 2 includes an inflatable bag 21 located at the front edge of the blade body 1; the inflatable bag 21 is connected to the side of the blade body 1 with a deformable rectifying structure 22; the rectifying structure 22 is located on the rear side of the inflatable bag 21. Since it is difficult to ensure a smooth transition between the shape of the inflatable bag 21 and the blade body after inflation, it is difficult to connect the inflatable bag 21 and the side of the blade body 1 to form a streamlined shape. By connecting the rectifying structure 22 between the inflatable bag 21 and the side of the blade body 1, when the inflatable bag 21 is inflated, the surface of the blade body 1 close to the inflated airbag 21 can remain streamlined through the connection of the rectifying structure 22, so that the surface of the blade body 1 is smoother after the inflatable bag 21 is inflated.

[0034] The angle between the protruding direction of the airbag 21 and the central symmetry line of the blade body 1 is 15° to 60°. The protruding direction of the airbag 21 is the direction in which the most protruding point of the airbag 21 is inclined relative to the central symmetry line of the blade body 1 after the airbag 21 is inflated. The specific angle between the protruding direction of the airbag 21 and the central symmetry line of the blade body 1 is determined according to factors such as the size of the blade body 1 and the distance between the blade body 1 and the rotation axis of the vertical axis wind turbine.

[0035] After the inflatable bag 21 is inflated, the top of the inflatable bag 21 is in an arc shape, so that the protruding point of the inflatable bag 21 can replace the leading edge of the blade body 1, thereby changing the leading edge of the blade, thereby changing the stall angle of attack of the blade, increasing the maximum lift coefficient of the blade, and being beneficial to improving the efficiency of the wind turbine.

[0036] The rectifying structure 22 is a flexible diaphragm, and the rectifying structure, the air-filled bag, and the blade body together form a closed space, and a through hole connected to the closed space is also provided on the blade body; the through hole connects the closed space with the interior of the blade body, and since the interior of the blade body is connected with the atmosphere, the closed space is connected with the atmosphere, so that after the air-filled bag 21 is inflated, the surface of the blade is streamlined, effectively preventing the formation of a discontinuous blade shape after the air-filled bag 21 is inflated.

[0037] The air supply system 3 includes an air pump 31 fixedly installed in the blade body 1, and a ventilation pipe 32 is connected between the outlet of the air pump 31 and the two air-filled bags 21; the air pump 31 is installed in the blade body 1 by screws, and the air inlet ends of the two ventilation pipes 32 are connected in parallel to the outlet end of the air pump 31, and the air outlet ends of the two ventilation pipes 32 pass through the blade body 1 and are connected to the two air-filled bags 21. In order to prevent the air outlet end of the ventilation pipe 32 from causing damage to the air-filled bags 21, the air outlet end of the ventilation pipe 32 is flush with the surface of the blade body; or two inflation nozzles for respectively inflating the two air-filled bags 21 can be installed on the blade body, and the air outlet ends of the two ventilation pipes 32 can be connected to the two inflation nozzles respectively.

[0038] The air pump 31 is a three-phase air pump, that is, the impeller in the air pump 31 can rotate forward and reverse, so that the air pump 31 can inflate the airbag 21 and discharge the air in the airbag 21, so that one air pump 31 can realize the inflation and exhaust of the airbag 21, making the structure simpler and the equipment cost lower.

[0039] The ventilation duct 32 is provided with a switch valve, which may be a solenoid valve. The switch valve controls the opening and closing of the ventilation duct 32, so that when one of the airbags 21 needs to be inflated, the solenoid valve can close the ventilation duct 32 corresponding to the other airbag 21, so as to prevent the inflation of the air pump 31 from affecting the other airbag 21. At the same time, the ventilation duct is controlled by the switch valve, so that after the inflation of the airbag 21 is completed, the corresponding ventilation duct can be closed by the solenoid valve, so that the airbag 21 is sealed, thereby eliminating the need to continuously blow air to the airbag 21 through the air pump 31.

[0040] Example 2

[0041] like Figure 2As shown, this embodiment 2 discloses a vertical axis wind turbine, in which the blade body 1 is mounted on the rotating shaft 6 through the bracket 4, and a power supply for powering the air pump 31 is embedded in the rotating shaft 6, and a relay is installed between the air pump 31 and the power supply; at the same time, an angle of attack sensor 5 is embedded in the bracket 4, and a controller is installed in the rotating shaft 6, the input end of the controller is connected to the output end of the angle of attack sensor 5, and the output end of the controller is respectively connected to the input ends of the relay and two switch valves; the angle of attack sensor 5 is a wind speed and direction sensor, and specifically a wind speed and direction sensor of model CFF-2D-3 can be used; the model of the controller is GD32F330RBT6, according to the angle of attack measurement result of the wind speed and direction sensor, when the controller can send a control signal to the relay, thereby realizing the control of the rotation of the air pump 31, when the controller sends a control signal to the switch valve, the switch valve is actuated, thereby realizing the control of the switch of the ventilation duct 32.

[0042] The angle of attack sensor 5 can effectively measure the flow velocity and flow direction of the wind, thereby determining the windward side and the leeward side of the blade. With the bracket 4 where the angle of attack sensor 5 is located as a reference, when the angle of attack is biased toward one end of the blade installation, the side of the blade close to the rotating shaft 6 is the windward side, and the other side of the blade is the leeward side; when the angle of attack is biased toward one end of the rotating shaft 6, the side of the blade away from the rotating shaft 6 is the windward side, and the other side of the blade is the leeward side.

[0043] In order to facilitate the detection of the air volume in the inflatable bag 21, an air volume sensor can also be installed on the inner wall of the two ventilation ducts 2. The air volume sensor can adopt a KGF2 air volume sensor. During the normal operation of the vertical axis wind turbine, the air volume of the inflatable bag 21 increases with the increase of the angle of attack. When the angle of attack reaches or exceeds 10°, the inflation volume reaches the maximum; at the same time, the air bag on the leeward side remains in an uninflated state.

[0044] like Figure 3 As shown, when the vertical axis force fan rotates counterclockwise, the direction of the wind is from left to right, and three blades are installed on the rotating shaft of the vertical axis force fan. The radius of the blade rotating around the rotating shaft of the vertical axis force fan is R, and the chord length of the blade is c. If a blade with a fixed curvature is used, due to the periodic rotation of the vertical axis wind turbine, the blade curvature plays a positive role in half of the rotation cycle, and the blade curvature plays a negative role in the other half of the cycle. The present invention adopts a method of dynamically changing the blade curvature, so that the blade curvature is adapted to the blade angle of attack, so that the blade curvature has a positive effect on the aerodynamic force in the entire cycle, thereby increasing the lift on the blade.

[0045] like Figure 4As shown, when the vertical axis wind turbine blade with deformable leading edge provided by the present invention is used, when the relative speed between the wind and the blade is Vr, the inflatable bag 21 located on the outside of the blade body 1 is tightly attached to the outside of the blade body 1, so that the outer side of the blade body 1 maintains the original shape of the blade body 1, and the air pump 31 inflates the inflatable bag 21 on the inside of the blade body 1 through the ventilation duct, so that the inflatable bag 21 on the inside of the blade body 1 swells, and the inflatable bag 21 on the inside of the blade body 1 swells, and the rectification structure 22 is straightened at the same time, so that the inflatable bag 21 and the rectification structure 22 jointly form the leading edge shape of the blade. Due to the change in the leading edge shape, the blade has a certain curvature, so that the blade generates a lift L at the angle of attack at this time, and the tangential projection La of the lift L is the power to drive the wind turbine to rotate. If the blade is an original symmetrical blade, the lift L' generated is smaller than the lift L of the blade with curvature, and the corresponding tangential projection is also smaller. Therefore, the leading edge of the vertical-axis wind turbine blade with a deformable leading edge provided by the present invention is conducive to improving the lift on the blade; on the other hand, the curvature of the blade can improve the dynamic stall characteristics of the blade, increase the stall angle of attack, and increase the maximum lift coefficient, so that the blade can reduce structural vibration and noise while improving the dynamic aerodynamic characteristics.

[0046] like Figure 5As shown, the vertical axis force fan rotates counterclockwise, and the wind blows from due west to due east. When the blade rotates to due north around the vertical axis wind turbine rotation axis, the angle of attack sensor measures that the blade's angle of attack is 0°, and the air bag 21 located on the outside of the blade body and the air bag 21 located on the inside of the blade body 1 are both tightly attached to the blade body 1. At this time, the blade shape is symmetrical, no lift is generated, and the resistance is small; when the blade rotates from due north to due west around the vertical axis wind turbine rotation axis, the angle of attack sensor can determine that the outside of the blade body 1 is the windward side, and the switch valve on the ventilation pipe corresponding to the air bag 21 inside the blade body 1 is closed, and the air pump 31 is supplied to the ventilation pipe corresponding to the air bag 21 outside the blade body 1. The switch valve is opened, and compressed air is introduced into the ventilation pipeline through the air pump 31. The compressed air entering the ventilation pipeline enters the inflatable bag 21 located on the outside of the blade, so that the inflatable bag 21 located on the outside of the blade is fully inflated, and the curvature of the blade gradually reaches the maximum. At this time, the lift on the blade is L, which is greater than the lift L' of the conventional symmetrical blade. At the same time, since the curvature of the blade plays a positive role, the lift of the blade is increased, and the dynamic stall angle of attack and the maximum lift coefficient are improved; when the blade rotates from due west to due south around the vertical axis wind turbine rotation axis, the blade angle of attack measured by the angle of attack sensor gradually decreases to 0°, and the air pump 31 rotates in the opposite direction through the ventilation pipeline, so that the air pump 31 The air in the inflatable bag 21 on the outside of the blade body 1 is evacuated, so that the inflatable bag 21 on the outside of the blade body 1 is tightly attached to the blade body 1, and the shape of the blade is restored to a symmetrical shape. At this time, the blade does not generate lift and the resistance is small; when the blade rotates from due south to due east around the vertical axis wind turbine rotation axis, the angle of attack sensor can determine that the inside of the blade body 1 is the windward side, and the angle of attack gradually increases, and the switch valve on the ventilation pipeline corresponding to the inflatable bag 21 on the outside of the blade body 1 is closed, and the air pump 31 opens the switch valve on the ventilation pipeline corresponding to the inflatable bag 21 on the inside of the blade body 1, and compressed air is introduced into the ventilation pipeline through the air pump 31, and the compressed air entering the ventilation pipeline enters the air in the blade. The air bag 21 on the side of the blade is completely inflated, so that the air bag 21 located on the outside of the blade is completely inflated, and the curvature of the blade gradually reaches the maximum. At this time, the lift on the blade is L, which is greater than the lift L' of the conventional symmetrical blade. At the same time, due to the positive effect of the curvature of the blade, the lift of the blade is increased, and the dynamic stall angle of attack and the maximum lift coefficient are improved; when the blade rotates from due east to due north around the vertical axis wind turbine rotation axis, the air pump 31 rotates in the opposite direction, so that the air pump 31 pumps air toward the air bag 21 on the inner side of the blade body 1 through the ventilation pipeline, so that the air bag 21 located on the inner side of the blade body 1 is tightly attached to the blade body 1, and the shape of the blade is restored to a symmetrical shape. At this time, the blade does not generate lift and has less resistance.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vertical axis wind turbine blade with a deformable leading edge, characterized in that: The invention comprises a symmetrical blade body (1), wherein airbag structures (2) are installed on both sides of the leading edge of the blade body (1), and the two airbag structures (2) are arranged symmetrically; one side of the airbag structure (2) is connected to the side surface of the blade body (1), and the other side of the airbag structure (2) is connected to the leading edge of the blade body (1) in a streamlined manner; an air supply system (3) for supplying air to the two airbag structures (2) is also installed inside the blade body (1); the airbag structure (2) comprises an inflatable bag (21) located at the leading edge of the blade body (1); the inflatable bag (21) is connected to the leading edge of the blade body (1); A deformable rectifying structure (22) is connected to the maximum thickness; the rectifying structure (22) is a flexible diaphragm, and the flexible diaphragm, the airbag structure (2) and the blade body (1) together form a closed space, and the blade body (1) is also provided with a through hole connected to the closed space; the air supply system (3) includes an air pump (31) fixedly installed in the blade body (1), and a ventilation pipeline (32) is connected between the outlet of the air pump (31) and the two inflatable bags (21); the air pump (31) is a three-phase air pump; and a switch valve is installed on the ventilation pipeline (32).

2. A vertical axis wind turbine, characterized in that: It comprises the blade as claimed in claim 1, and also comprises a rotating shaft and a bracket mounted on the rotating shaft, wherein the blade is mounted on the bracket, and an angle of attack sensor is also embedded on the bracket.

3. The vertical axis wind turbine according to claim 2, characterized in that: A power supply and a controller are also installed in the rotating shaft, the input end of the controller is electrically connected to the output end of the angle of attack sensor, and the output end of the controller is electrically connected to the air supply system (3).

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