CN106286122A - A kind of band bilayer lift strengthens and rises the vertical axis windmill hindering automatic switching foil - Google Patents

Abstract

The invention relates to a vertical-axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades, which consists of outer blades, inner blades, inner blade rotating shafts, supporting connecting rods, wind turbine main shafts, lift limit stoppers, and resistance limiters. block etc. The wind turbine is rotated by several inner and outer blades. Both the inner and outer blades have a lift-type aerodynamic shape. The outer blades are fixed to the main shaft of the wind turbine through two supporting connecting rods to form a basic frame of an H-shaped wind turbine; the inner blades can freely rotate about 90 degrees between the two supporting connecting rods through the rotating shafts on both ends. When the wind speed is low, the inner blade working on the windward side of the wind turbine is close to the resistance limit stopper, and the resistance of the blade drives the wind turbine to rotate; on the side wind or the leeward side, the inner blade is free to rotate to the windward angle with less resistance. When the wind speed is high, the inner blade is close to the lift limit block, and the inner blade provides enhanced lift for the wind turbine, which realizes the automatic conversion of the lift resistance of the blade, and improves the low-speed start-up capability and effective output of the lift-type wind turbine.

Description

A vertical axis wind turbine with double-layer lift enhancement and lift-drag automatic switching blades

technical field

The invention relates to the field of wind turbines, in particular to a vertical axis wind turbine with dual-layer lift enhancement and lift-drag automatic switching blades.

Background technique

According to the working principle of wind turbine blades, vertical axis wind turbines can be divided into two types: lift type and drag type. The lift-type wind turbine relies on the lift generated by the blades in the wind field to drive the wind turbine to rotate. The representative vertical-axis lift-type wind turbine is the Darrieux-type wind turbine, among which small wind turbines with straight blades in the shape of H are more common.

The characteristic of the lift-type wind turbine is that when the tip speed ratio (the ratio of the blade linear speed to the wind speed) reaches a reasonable range, its wind energy utilization rate is high, but if the wind speed is low when it is started, the torque generated by the blades is very low. Small, almost no self-starting ability.

The drag-type wind turbine is a wind turbine that relies on the difference between the effective thrust torque on the windward side of the blade and the resistance torque on the other side to drive the wind wheel to rotate and do work. The S-type resistance wind turbine is more representative.

Because the tip speed ratio of the resistance type blade cannot be greater than 1 (the linear speed of the blade cannot be greater than the wind speed), its wind energy utilization rate is low. However, its starting torque is large, and it can generate electricity in light wind conditions.

In order to meet the demand for power generation where the wind resources are not very abundant and the wind speed stability is poor, some people install two kinds of blades on the same shaft. When the wind speed is small, the resistance blades drive the wind turbine to start, and the speed of the wind turbine is accelerated to the lift blades, which is ideal. speed range, the wind turbine generates electricity.

The above method of simply combining the lift type and the drag type can alleviate the low wind speed start-up problem of the traditional lift type vertical axis wind turbine, but it also brings other problems that hinder the wind energy conversion efficiency of the fan. Because the tip speed ratio corresponding to the efficient work of the lift-type blade is above 4, and when the fan reaches this speed, the tip speed ratio of the coaxially rotating resistance-type blade is often greater than 1. The generated torque is in the opposite direction, and the resistance blades hinder the rotation of the wind turbine. In order to reduce the probability of this happening, the radius of the resistance-type S-shaped blade is generally reduced as much as possible to avoid its tip speed ratio being greater than 1, but the result of this will seriously affect the wind turbine's ability to adapt to wind speed changes and Starting performance at low wind speeds.

Contents of the invention

Technical problem: Aiming at the problem that the wind turbine with vertical axis lift type and resistance type has a small starting torque and the resistance type blades are prone to negative torque at high speed, the present invention designs a double-layer lift enhancement and lift-drag wind turbine. Vertical axis wind turbine with automatic blade switching.

When the wind turbine is working normally, the outer lift-type blades provide the main power for the wind turbine, and the lift generated by the inner blades provides enhanced torque for the wind turbine; when the wind speed is low, the inner movable blades are converted into drag-type, generating The large torque drives the wind turbine to rotate at a low speed and generate electricity; as the external wind increases, the wind turbine speed gradually increases. When the linear velocity at the inner blade exceeds the wind speed, the resistance blade is converted into a lift blade under the action of the wind. , while effectively reducing the drag torque of the wind turbine, it provides a beneficial lift for the wind turbine to rotate and do work, thereby improving the wind energy utilization rate of the wind turbine.

Technical solution: The present invention is a vertical-axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades, which consists of outer blades, inner blades, inner blade shafts, bearings, supporting connecting rods, wind turbine main shafts, and lift limit stops. , resistance limit block and other components.

The wind turbine is rotated by several coaxial outer blades and inner blades, and the main shaft of the wind turbine outputs power.

The outer blades are straight blades and have the aerodynamic shape of common lift-type wind turbine blades.

The outer blades are longitudinally parallel to the shaft of the wind turbine, and each is fixedly connected to the main shaft of the wind turbine through two upper and lower supporting connecting rods arranged in parallel, forming a wind turbine similar to an H shape.

The inner blade is also a straight blade, which has the aerodynamic shape of a lift-type blade, and the inner blade rotating shaft is arranged at the aerodynamic center of the two transverse end surfaces of the blade (1/4 of the chord length of the aerodynamic blade).

The proper position of the supporting connecting rod middle part is provided with a bearing cooperating with the inner blade rotating shaft, so that the inner blade can rotate freely in the upper and lower supporting connecting rods around its rotating shaft.

The support link is provided with a resistance limit stopper, which is used to limit the rotation range of the tail of the inner blade; the support link is also provided with a lift limit stopper, which is used to limit the blade angle after the inner blade changes from resistance to lift .

Furthermore, the main shaft of the wind turbine is the mechanical transmission main shaft of the vertical axis wind turbine of the present invention, which is responsible for transmitting the torque and rotational motion generated by the blades to the generator, and the main shaft of the wind turbine is installed vertically to the ground.

Further, the outer blades of the wind turbine have the aerodynamic shape of the lift-type wind turbine blades, such as general-purpose NACA series or other lift-type airfoils, and the blades are evenly distributed on the circumference of the wind turbine.

Further, the outer blade is installed parallel to the main shaft of the wind turbine, and is fixedly connected to the main shaft of the wind turbine through two parallel support links at a suitable position in the longitudinal direction of the outer blade. If the two parallel support links are regarded as a whole, then the The outer blades at both ends form an "H" shape with the connecting rod.

Further, the inner blade also has the aerodynamic shape and size of a lift-type blade, and is installed between the above-mentioned two parallel supporting rods, generally parallel to the outer blade and leaving a free rotation space for the inner blade; The inner blade shaft is set near the aerodynamic center of the blade on the transverse end surface (1/4 of the chord length of the aerodynamic blade). between, so that the inner blade can freely rotate around its rotating shaft between the upper and lower supporting connecting rods.

Further, the resistance limit block is arranged on the support connecting rod close to the main shaft of the wind turbine. The stopper contacts with the afterbody of inner blade, limits inner blade and continues to rotate.

Further, the lift limit stopper is arranged on the support connecting rod close to the shaft of the inner blade, and is used to limit the rotation of the inner blade until its chord line is nearly perpendicular to the support connecting rod (the corresponding blade changes from resistance to lift type, Inner blade about 90 degree angle), do not continue to rotate.

The inner blade of the wind turbine is limited by the resistance limit block and the lift limit block, and automatically changes the windward angle around its rotating shaft along with the size of the wind force. At low wind speed, the resistance limit block limits the rotation angle of the blades, and the resistance reaction force of the inner blades to the wind drives the wind turbine to rotate; when the wind force increases to a certain level, the inner blades turn against the lift limit block under the action of the wind force. When the inner blade is parallel to the outer blade, the resistance decreases, and the lift becomes its main driving force.

The rotating shaft of the inner blade can be arranged as far away from the main shaft of the wind turbine as possible, so that the torque generated by the inner blade is relatively large when it works in the resistance stage, which improves the acceleration performance and wind speed adaptability of the wind turbine, and improves the utilization rate of wind energy.

Beneficial effect: the beneficial effect of the present invention is:

A vertical-axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades is designed. The main shaft of the wind turbine is driven to rotate by several coaxial outer blades and inner blades, and the main shaft of the wind turbine outputs power generation. When , the lift generated on the inner blades can enhance the output torque of the wind turbine and improve the utilization rate of wind energy of the wind turbine.

When the wind force is small, the inner blade will transform its windward angle under the action of wind resistance, and when the wind turbine rotates to the best position where the resistance plays a role, the windward angle becomes about 90 degrees to obtain the best windward driving force; On the other half of the circumference, the blades will rotate freely until the windward angle becomes about 0 degrees, the aerodynamic resistance is the smallest, and the fan shaft obtains the largest resistance difference. At this time, the wind turbine is a resistance type, and the inner blades provide the wind turbine with high torque at low speed for rapid start-up of the wind turbine or low wind speed power generation.

After the wind speed increases to a certain extent, the inner blade will follow the principle of the minimum resistance of the aerodynamic blade under the combined action of wind resistance and blade centrifugal force, so that the windward angle becomes smaller, and finally the limit stop restricts the continued rotation of the blade, and the inner blade is completely transformed into Same lift type as the outer blades.

Description of drawings

Figure 1 is a schematic diagram of the structure and principle of a vertical axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades;

Figure 2 is a top view of the mutual positions of the starting points of the blades when the linear speed of the blades in the wind turbine is lower than the external wind speed;

Figure 3 is a top view of the mutual position of the blades rotating 45 degrees when the linear speed of the blades in the wind turbine is lower than the external wind speed;

Fig. 4 is a top view of the mutual position of the blades when the linear speed of the blades in the wind turbine is greater than the external wind speed.

In the figure: 1-outer blade, 2-inner blade, 3-inner blade rotating shaft, 4-bearing, 5-support connecting rod, 6-lift limit stopper, 7-resistance limit stopper, 8-fan main shaft.

detailed description

The embodiment of the present invention provides a vertical axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades, which drives the wind turbine to rotate through the inner and outer two-layer blades to provide power for the generator. The outer blades are fixedly installed with the main shaft of the wind turbine, and provide torque for the wind turbine with the lift generated in the flow field.

In this embodiment, both the outer blade and the inner blade adopt the aerodynamic shape of the NACA0012 standard blade. During the rotation of the wind turbine, the inner blade swings freely in a specified space through the rotating shaft, so that when the wind turbine starts or runs at a low speed, The windward side of the inner blade works in the state of the resistance blade, and the blade on the leeward side automatically turns to a position with little resistance; after the speed of the wind turbine increases to a certain extent, the inner blade automatically switches to the state of the lift blade, together with the outer blade The lift type power is provided for the wind turbine, and the utilization rate of wind energy of the wind turbine is improved.

The following will clearly describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by persons of ordinary skill without creative efforts all belong to the protection scope of the present invention.

1 to 4, the vertical axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades of the present invention consists of outer blade 1, inner blade 2, inner blade rotating shaft 3, bearing 4, supporting connecting rod 5, lift limiter Block 6, resistance limit block, 7, fan main shaft 8 etc. are formed.

The outer blade 1 and the inner blade 2 are evenly distributed in two layers on the rotation circumference of the wind turbine, the outer blade is fixedly connected to the main shaft 8 of the wind turbine through two parallel support connecting rods 5, and the inner blade 2 is connected through the inner blade on it. The rotating shaft 3 forms a rotatable hinge connection with the inner blade bearing 4 supporting the middle part of the connecting rod 5 .

A lift limit stopper 6 and a resistance limit stopper 7 are arranged on the support link 5 to limit the rotation angle of the inner blade 2 so that it can complete the conversion of lift and resistance working modes within a specified rotation range.

As shown in Figure 1, the four outer blades 1 are evenly distributed on the circumference of the wind turbine main shaft 8 through the parallel support connecting rod 5 and the wind turbine main shaft 8, and the installation angle of the blades conforms to the general lift type vertical axis wind turbine aerodynamic blade installation. specification to obtain a reasonable wind angle of attack.

As shown in Figure 1, 4 inner blades 2 are installed in the bearing 4 corresponding to the middle part of the supporting connecting rod 5 through its inner blade rotating shaft 3, and the inner blade is supported by two supporting connecting rods up and down, and can freely rotate around its rotating shaft.

As shown in Figure 1, a resistance limit block 7 is set on the support link 5 close to the main shaft 8 of the wind turbine, which is used to limit the tail of the inner blade 2 from rotating through the support link; The limit block 6 is used to limit the rotation angle of the inner blade 2 in another direction, so that the maximum angle between the chord line of the inner blade and the supporting link is basically the same as the fixed angle of the outer blade.

In order to reduce the impact, the resistance limit block 7 and the lift limit block 6 are provided with a buffer device (not marked in the figure), and a collision buffer structure (not marked in the figure) is designed at the corresponding position of the inner blade 2, Improve the safety of the collision between the inner blade and the limit stopper.

As shown in Figure 2, the wind turbine is rotating and the linear velocity at the inner blade is lower than the external wind speed. The top view of the mutual position of the starting points of the blades. The description is as follows: when the wind turbine is started or at low speed, under the action of the wind, the inner blade 2 at 12 o’clock is at the horizontal position where the head faces the wind according to the principle of minimum resistance; the inner blade 2 at 9 o’clock The tail is deflected to the center direction due to the joint effect of wind force and centrifugal force (very small at this time); the inner blade 2 in the direction of 6 o'clock will rotate to the As far as the contact resistance limit stopper 7 is reached, the windward angle of the inner blade is nearly 90 degrees at this moment, the resistance on the aerodynamic blade is the largest and the lift is very small, and the torque generated by the resistance on the wind turbine reaches the maximum value; The wind force at the tail of the blade 2 quickly reverses the inner blade 2 to the position in contact with the lift limit stopper 6. At this time, the head of the inner blade 2 is in the same direction as the wind turbine rotating forward, and the wind force produces the largest resistance on it, but Due to the small torque, it has little effect on the output torque of the wind turbine; in the direction of 0 o'clock, the inner blade 2 adjusts the head position according to the principle of minimum resistance, so that the negative resistance on the leeward side is reduced to the minimum.

When the wind turbine starts or rotates at low speed, a more detailed description of the state of the inner blades is shown in Figure 3. The state shown in the figure is the attitude of the inner blades when the wind turbine rotates 45 degrees counterclockwise from the initial state shown in Figure 2. The blade rotates to the direction of 10:30, and the inner blade is subjected to the combined action of wind force and centrifugal force. Due to the low speed of the wind turbine, the wind resistance at the tail of the inner blade is greater than the centrifugal force, and the tail is drawn toward the direction of the wind turbine shaft; similarly, the inner blade passes through 9 o'clock. And after the 7:30 position, realize the attitude of 6 o'clock shown in Figure 2. In the direction of 4:30, the wind force on the inner blade keeps its tail in contact with the resistance limit stopper; because the wind force may be unstable, the tail of the inner blade will flip sharply at an uncertain interval around 3 o’clock, Until it hits the lift limit block; as shown in Figure 3, at the 2:30 position, the resistance formed by the wind-receiving surface at the tail of the inner blade will make the inner blade close to the lift limit block, and produce a force that blocks the forward rotation of the wind turbine. Negative torque, but because the distance between the resistance direction and the main shaft of the wind turbine is small, the total resistance distance is small; as the blades continue to rotate toward the zero point, the windward angle of the inner blades gradually decreases, and the resistance gradually decreases.

As shown in Figure 4, as the wind speed increases, the speed of the wind turbine continues to increase, and the lift effect of the outer blades will gradually appear, and the speed of the wind turbine will continue to increase, so that the linear speed of the blade exceeds the wind speed (the tip speed ratio is greater than 1). When the linear velocity of the inner blade is greater than the external wind speed, under the action of the wind, the inner blade 2 in the direction of 12 o'clock is the horizontal orientation of the head facing the wind; large) and wind resistance, so that the inner blade is close to the lift limit block; the inner blade 2 in the direction of 6 o’clock, because its linear velocity has exceeded the wind speed of the wind field, the inner blade will be under the combined action of centrifugal force and relative wind speed Keep close to the lift limit block; similarly, the blades in the following links will always keep in contact with the lift limit block 8 until the wind turbine speed drops to the point where the linear velocity of the inner blade is less than the wind speed, and returns to the state shown in Figure 2 .

As mentioned above, in the whole cycle shown in Figure 4, the inner blade 2 and the supporting link 5 do not move relative to each other, and the inner blade 2 is always kept parallel to the outer blade 1, forming two lift-type blades inside and outside to drive the wind force together. machine turns.

The working process of the lift type outer blade 1 is no different from that of the common vertical axis lift type wind turbine, and does not belong to the content of the present invention, so it will not be repeated.

A vertical axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades provided by the present invention has been introduced in detail above. There will be changes in the scope of application and the scope of application. In summary, the content of this specification should not be construed as limiting the present invention.

Claims (7)

1. A vertical-axis wind turbine with double-layer lift enhancement and lift-drag automatic conversion blades, including outer blades, inner blades, inner blade shafts, bearings, supporting connecting rods, wind turbine main shaft, lift limit stoppers, and resistance limiters. The outer and inner blades have the aerodynamic shape of the lift-type blades, which are installed in two layers, which drive the wind turbine to rotate on the same axis; the inner blade shaft is set near the aerodynamic center of the inner blade so that the inner blade can rotate around it. The rotating shaft rotates freely between the upper and lower supporting links; a resistance limit stop is set on the support link to limit the rotation range of the tail of the inner blade; a lift limit stop is set on the support link to limit the inner The blade angle after the blade changes from drag to lift. 2. A vertical axis wind turbine with double-layer lift-enhancing and lift-drag automatic conversion blades according to claim 1, characterized in that the inner blades have an aerodynamic shape and conform to the aerodynamic characteristics of general standard lift-type blades , that is, when the windward angle of the blade is small, the lift force generated is large and the resistance is small. When the windward angle is 90 degrees, the lift force drops to a very low level and the resistance reaches the maximum value. 3. A kind of vertical axis wind turbine with double-layer lift enhancement and lift-drag automatic switching blade according to claim 1, characterized in that the inner blade rotating shaft is set at (or near) the inner blade aerodynamic center, so that the inner blade can Rotate between the upper and lower two support connecting rods around its axis of rotation. 4. A vertical axis wind turbine with double-layer lift-enhancing and lift-drag automatic switching blades according to claim 1, characterized in that when the inner blade rotates around its axis of rotation between the upper and lower support connecting rods, Limited by the lift limit stop and the drag limit stop. 5. A vertical-axis wind turbine with double-layer lift-enhancing and lift-drag automatic conversion blades according to claim 1, characterized in that the resistance-type limit stopper restricts the inner blade from rotating to its chord length line and the support The included angle of the connecting rod axis ends at a position near 0 degrees, so that the inner blade works in a resistance mode. Obviously, the actual angle of the inner blade can be adjusted within a certain range according to the actual structure and use effect of the wind turbine. 6. A vertical-axis wind turbine with double-layer lift-enhancing and lift-drag automatic conversion blades according to claim 1, characterized in that the lift-type limit block restricts the inner blade from rotating to its chord length line and the support The included angle of the connecting rod axis ends at a position near 90 degrees, so that the inner blade works in a lift mode. Obviously, the actual angle of the inner blade can be adjusted within a certain range according to the actual structure and use effect of the wind turbine. 7. A vertical axis wind turbine with double-layer lift-enhancing and lift-drag automatic conversion blades according to claim 1, characterized in that said resistance and lift limit stoppers are provided with buffer devices, and the inner blades Measures such as buffer pads are provided at the contact part with the stopper to reduce the impact between the blade and the stopper and improve the service life of the wind turbine.