RU2251023C1 - Windmill orthogonal rotor - Google Patents

Abstract

FIELD: wind power engineering.

SUBSTANCE: invention is designed for use in windmills whose rotating blades are parallel to axis of rotation. Proposed rotor contains rotating shaft designed for mounting in one or more supports of windmill, and one or several brackets secured on rotating shaft and equipped with brake panel. Wind profile rotating blade is rigidly secured on each bracket parallel to rotation shaft. Brake panel is connected with angular speed pickup through kinematic coupling unit, and is connected through elastic coupling element with rotor member stationary relative to rotating shaft.

EFFECT: improved aerodynamic characteristics, increased efficiency, provision of limiting of rotor speed and accuracy of maintaining its nominal value.

15 cl, 8 dwg

Description

Technical field

The invention relates to the field of wind energy and is intended for use in wind turbines, the rotating blades of which are parallel to the axis of rotation. The rotors of such engines are called orthogonal, since the axis of their rotation is orthogonal to the direction of air flow. Orthogonal rotors are typically used in wind turbines with a vertical axis of rotation, since they do not need to be oriented in the direction of the wind.

The level of technology.

Known orthogonal rotor of a wind turbine containing a rotation shaft designed to be placed in a vertical support stand of the wind turbine, and brackets fixed to the rotation shaft, each of which is equipped with a vertical wing-shaped blade (vertical wing) and a brake flap. In this case, the blade and the brake flap are mounted with the possibility of rotation about the axis of the bracket and are fixed on the outer end of the torsion bar (elastic to twist the rod), the inner end of which is fixed to the base of the bracket (patent RU 2039309, IPC F 03 D 7/06 [1]).

In the device [1], the blades, in addition to the main function (rotor rotation), perform the function of an angular velocity sensor that rotates about the axis of the bracket with increasing angular velocity. The rotation of the blade - the sensor - relative to the axis of the bracket causes the rotation of the brake flap mounted on the same end of the torsion bar, as a result of which the aerodynamic resistance of the rotor increases and the maximum frequency of its rotation is limited.

The torsion bar in the device [1] performs the function of an elastic element holding the blade and shield in the initial position corresponding to the minimum aerodynamic drag.

The disadvantage of the technical solution [1] is the high requirements for the torsion bar, the weakness of the blade attachment (it is attached at one point to the torsion bar) and the large cantilever flights of the blade relative to the attachment point. An additional technical solution proposed there to strengthen the blade fastening with profiled guy rods required the introduction of an additional rotating support at the base of the bracket, which complicates and increases the cost of the design.

In addition, the rotation of the brake flap and the blade at the same angle leads to the fact that the maximum rotational speed of the rotor is significantly higher than the nominal frequency (1.4 times).

Known as a prototype orthogonal rotor of a wind turbine is known, comprising a rotation shaft intended for installation in a vertical support stand of the wind turbine and brackets fixed to the rotation shaft, on each of which a wing-shaped rotary blade is rigidly fixed (patent RU 2136960, IPC F 03 D 7 / 06 [2]. In the prototype device, each bracket (called a traverse in [2]) is equipped with a half-wing acting as a brake flap and rigidly fixed on the end part of the half-wing with an additional blade of reduced dimensions, which performs the function of an angular velocity sensor, for which a half-wing is mounted rotatably relative to the axis of the bracket, which is hollow and equipped with a torsion bar, the ends of which are fixed in the root parts of the bracket and half-wing.

Due to the rigid connection of the main blade with the bracket, it can be made oversized and without the use of auxiliary bearing units mounted on the shaft of rotation of the rotor with additional brackets, profiled guy wires or other structural elements, stationary relative to the shaft of rotation. The reduced dimensions of the additional blade reduce the requirements for the torsion bar, which accordingly reduces its size, weight and cost.

The disadvantage of the prototype is additional aerodynamic losses and reduced efficiency in the nominal speed mode.

This is due to the fact that the additional blade performing the function of the angular velocity sensor in the rotor prototype is fixed together with the wing on the outside of the main rotating blade and therefore obscures it from the wind, reducing the pulling force. This decrease in the pulling force of the main rotary blade is not compensated by the fully pulling force of the additional blade.

Another reason for additional aerodynamic losses, common to devices [1] and [2], is that the brake flap begins to rotate and leaves the horizontal position corresponding to the minimum aerodynamic losses, prematurely - even before the rotor reaches its rated speed.

The objective of the invention is to improve aerodynamics, increase efficiency, reliability of limiting the rotor speed and accuracy of maintaining its nominal value.

Disclosure of invention

The subject of the invention is an orthogonal rotor of a wind turbine, comprising a rotation shaft, intended for installation in at least one support of the wind turbine, and at least one bracket fixed to the rotation shaft and provided with a brake flap, on which a rotating blade is rigidly fixed parallel to the rotation shaft wing-shaped profile, while the brake flap through the kinematic connection unit is connected to the angular velocity sensor and through an elastic element is connected to the rotor design element, motionless no rotation of the shaft.

This set of features can improve the aerodynamics and efficiency of the rotor.

The invention has a development.

One of them is that the angular velocity sensor is installed with a deviation of its axis from the plane of the brake flap by 70-90 degrees, and the elastic element is pre-stressed by an additionally introduced displacement limiter.

This improves the accuracy of maintaining the nominal value of the rotational speed and the reliability of its limitation by an acceptable value while maintaining the improved aerodynamic qualities and rotor efficiency.

Another development of the invention is that the kinematic communication unit can be made in the form of a rotation shaft or in the form of a multiplier, on a slow-moving shaft of which an angular velocity sensor is located, and on a high-speed one - a brake flap. In this case, the multiplier can be made either on the basis of a gear (cylindrical or bevel) or chain transmission, or on the basis of a lever-hinge mechanism. Using the multiplier as a kinematic communication unit can further improve the stabilization efficiency of the nominal shaft speed, and the choice of multiplier modifications allows you to optimize the design layout of the rotor elements in particular cases of its execution. The preferred transmission coefficient of the multiplier is in the range from 2 to 5.

For a special case of the implementation of the rotor with two or more brackets, the further development of the invention provides for the possibility of kinematic communication between all the brake flaps of the rotor using a common element (for example, a bevel gear) introduced into the kinematic communication unit.

This allows for better balance of the rotor during braking by the shields.

Other development of the invention include various versions of the elastic element:

- in the form of one torsion placed in the cavity of the kinematic communication unit;

- in the form of a torsion spring, covering the shaft of the kinematic communication unit;

- combined - in the form of one torsion bar and torsion kinematically connected with it;

as well as various options for placing the angular velocity sensor:

- on the bracket;

- in a cavity made in a rotating blade;

- in a hollow hub made on a shaft of rotation.

These developments allow optimizing the design of the rotor in particular cases of its implementation.

Another development of the invention provides for two-console implementation of the bracket with the brake flap on the main console of the bracket, and the angular velocity sensor on its additional shortened console.

This modification of the rotor design allows the use of a torsion with a large ratio of length to diameter as an elastic element, which reduces the shear stresses that arise in the torsion when it is twisted.

Brief Description of the Drawings

Figure 1-4 illustrate an example embodiment of the invention (taking into account its development) in a three-blade rotor. Figure 1 and 2 shows an example of a rotor with two-console brackets, figure 3 and 4 with single-console. In Fig.1, 3 presents a General view of the rotor installed in the support rack of the wind turbine, Fig.2, 4 - its view in plan. Figure 5, illustrating an example of the placement of the sensor on a single-console bracket, presents a transverse section of the bracket in a plane passing through the axis of the sensor. 6 illustrates an example of a multiplier with its placement in the hub of the rotation shaft. 7 and 8 illustrate the reinforcement of the mounting of the blades with additionally installed guy wires.

The implementation of the invention

Figure 1-4 shows:

1 - support of a wind turbine;

2 - shaft of rotation of the rotor installed in the support 1;

3 - the hub made on the shaft 2;

4 - brackets mounted on the hub 3 (see Fig.3, 4);

5 - rotating wing-shaped blades mounted on brackets 4;

6 - brake flaps, which are equipped with brackets 4;

7 - rotation shafts, representing a special case of the execution of the kinematic communication unit;

8 - rotor angular velocity sensors, each of which is connected by a shaft 7 to the brake flap 6;

9 - the main bracket bracket (see figures 1 and 2);

10 - additional shortened bracket bracket (see figures 1 and 2);

11 - elastic elements made in the form of torsions;

12 - limiters of angular displacement.

Presented in figures 1-4, an example implementation of the invention relates to a rotor with a shaft 2, designed for vertical installation in one support 1 of a wind turbine. In places with a predominant or constant wind direction (for example, in gorges), the invention can be implemented (with an obvious change in the figures) with a shaft 2 intended for horizontal installation in two supports 1.

Figures 1 and 2 show an example of a rotor with two-console brackets 4, when the brake flaps 6 are placed on the peripheral end of the main consoles 9 of the bracket 4 behind the blades 5, and the sensors 8 are located on additional shortened consoles 10 mounted on the opposite side of the hub 3.

Figures 3 and 4 show an example of a rotor with single-console brackets, when the brake flaps 6 are also located on the periphery of the brackets, and the sensors 8 are placed in the cavity of the hub 3.

Shown in figures 1 to 4, the hub 3, the brackets 4 and the shields 6 are made hollow. In the cavity of each bracket 4, the hole made in the blade 5, and in the cavity of the hub 3 is a shaft 7.

The brackets 4 or its console 9 and 10 (in the case of a two-console version) are made in the form of a pipe closed by a cowl.

Figure 1 - 4 shows the simplest embodiment of the kinematic connection between the shield 6 and the sensor 8 - they are rigidly fixed to a common shaft 7. In this case, the sensor 8 is installed perpendicular to the shaft 7, and the shield 6 so that the axis of the shaft 7 lies in its plane .

In the example shown in FIGS. 1 and 2, the sensors 8 are made in the form of short wing-shaped blades mounted on an additional shortened console 10; FIGS. 3 and 4 show an example of sensors in the form of rods placed in the hollow hub 3. In FIG. .6 shows the case of the sensor 8 in the form of a dumbbell.

Shafts 7 and 1 shown in FIGS. 1 and 2 intersect inside the hub 3. Therefore, they are made vertically offset from each other by an amount slightly larger than the diameter of these shafts.

Each shaft 7 is made in the form of a pipe of circular cross section, inside which a torsion bar (long thin rod) 11 is placed, which performs the function of an elastic element. One (rotary) end of the torsion bar 11 is attached to the flap 6 (see node A in figure 1), and the other (fixed) to the rotor structure element, fixed relative to the shaft 2. In the example shown in figures 1, 2, fixed the end of the torsion bar is attached to the console 10, and in Fig.3. 4 - to the fastening element 13 (see node A in figure 3) installed in the cavity of the hub 3. The end of the torsion 11 is secured to the console 10 also by means of the corresponding fastening element (not shown in the figures), which is located in the slots made in the walls of the hollow shaft 7.

Another possible option for the placement of the sensor 8 in a single-console implementation of the bracket (not requiring a hollow hub on the shaft 2) is illustrated in FIG. 5, in which the sensor 8 is located on a portion of the shaft 7 extending inside the bracket 4. As shown in FIG. 5 in the wall of the bracket 4 made in the form of a pipe closed by a fairing, there are slots 14 for accommodating the sensor 8, which in the initial state abuts against the limiter 12.

It is also possible placement of the sensor 8 in the cavity made in the blades 5, not shown in the figures.

In the examples of the rotor shown in figures 1-4, the shield 6 is placed behind the blade 5. It is also possible, for example, to place the shield 6 on the inside of the blade 5, used in [1].

As can be seen in figure 2 (view along arrow C) and figure 5, the sensor 8 is mounted on the shaft 7 with a slight slope of α ₀ degrees relative to the vertical axis (α ₀ does not exceed 20 °). The shield 6 in the initial state occupies a horizontal position, and, therefore, the angle between the plane of the shield 6 and the axis of the sensor 8 mounted on the shaft 7 is (90 - α ₀ ) degrees. In this case, the elastic element 11 using the limiter 12 of the angular displacement is pre-stressed so that the angle of twist is also α ₀ degrees.

The kinematic communication unit can be made in the form of a multiplier. Figure 6 shows, by way of example, a multiplier having a low-speed shaft 15, a high-speed shaft 16, and an angular displacement transducer in the form of cylindrical gears 17 and 18 mounted on these shafts. The shafts 15 and 16 are installed in the bearing bearings 19. A sensor 8 is fixed on the shaft 15, and a shield 6 is mounted on the shaft 16, which is not shown in Fig. 6. An elastic element made in the form of a torsion bar 11 is placed in the cavity of the shaft 16. The fixed end of the torsion bar 11, as in FIG. 3 (node A), is fixed by the element 13, and the other (movable) end is fixed in the cavity of the shield 6 as shown figure 1 (node A). It is also possible to install a second torsion bar inside the hollow shaft 15.

The elastic element 11 can be made in the form of a spring of any type with appropriate devices, for example, in the form of one or more torsion springs covering the shafts of the kinematic coupling unit (shaft 7 in Figs. 1-4 or shafts 15 and 16 shown in Fig. 6 ) In this case, one of the ends of the torsion spring is attached to the corresponding shaft, and the other to any structural element of the rotor, stationary relative to the shaft 2.

It is also possible to use a combined elastic element in the form of a torsion bar and a torsion spring kinematically connected with it. In this case, for example, a torsion bar is placed in the shaft 15, and the shaft 16 is covered by a torsion spring. In another case, a torsion bar can be placed in each of the shafts 15 and 16 and each of the shafts is surrounded by a torsion spring.

The possibility of using elastic elements of various types allows optimizing the design of the rotor in particular cases of its implementation.

The converter of angular movements of the multiplier can also be made on the basis of a lever-articulated mechanism, a bevel gear or chain transmission.

Shown in Fig.6, the angular displacement transducer together with the sensor 8 is placed in the hub 3. Other options for their placement are possible - in the cavities of the bracket 4 or blades 5.

The use of the multiplier as a kinematic communication unit can further improve the stabilization efficiency of the nominal speed of the shaft 2 by increasing the angle of rotation of the shield 6 compared with the angle of rotation of the sensor 8.

The use of various options of the multiplier instead of the rotation shaft allows you to expand the design capabilities of the layout of additional consoles 10 with sensors 8 relative to the main consoles 9 (placement of consoles 9 and 10 at an angle to each other or under each other).

A common element can be introduced into the kinematic communication unit, for example, a bevel gear connecting all the brake flaps.

This allows for more accurate central symmetry of the rotor elements when the brake flaps 6 deviate from the initial position and thereby improve the balance of the rotor during braking.

With the increase in the size of the blades 5, their fastening can be strengthened with the help of additionally installed brackets and / or streamlined braces. 7 and 8 show an example of a rotor with reinforcing the fastening of the blades 5 by guy wires 20, which connect additional elements of the hub (rack 21 and skirt 22) with blades 5.

The rotor installed in the support rack 1 of the wind turbine operates as follows.

In the initial position (in the absence of wind), the rotor is stationary, and the shield 6 is installed in a plane perpendicular to the shaft 2. At the same time, the aerodynamic drag of the shield 6 is minimal, and the axis of the sensor 8 kinematically connected to the shield 6 is inclined relative to the vertical shaft 2 by an angle α ₀ degrees. The shield 6 and the sensor 8 are held in this position by means of a limiter 12 and an elastic element 11, for example a torsion bar, the preliminary twisting angle of which is also α ₀ degrees.

In the range of operating wind speeds, starting from a certain minimum value, and when there is no load on the shaft 2, the rotor starts automatically - the blades 5 begin to rotate the shaft 2, gradually accelerating their movement under the influence of the wind. Forced start and acceleration of the rotor is also possible. In more detail, the principle of action of orthogonal rotors is described, for example, in the article: Historian B.L., Shpolyansky Yu.B. The study of a vertical wind turbine with aerodynamic regulation. / Energy construction / 1991, No. 3, p. 37-39.

When the rotor speed exceeds a certain value (the linear speed of the circular motion of the blade 5 is several times higher than the wind speed), the load is connected, for example, in the form of a consumer of electricity generated by a generator mounted on the shaft 2. In this case, the work of a loaded rotor with a variable or constant speed. In both cases, however, the rotor speed must not exceed a certain nominal value n _p , after which centrifugal forces acting on the rotor can be dangerous. While the rotor speed is less than n _p , the prestressed elastic element 11 does not allow the shield 6 and the sensor 8, rigidly connected to each other through the kinematic communication unit, to leave the initial position defined by the limiter 12.

If for any reason (increase in wind speed, decrease in load on shaft 2, for example, due to emergency shutdown of the consumer), the rotor speed will exceed the nominal, the shield 6 should provide aerodynamic braking of the rotor.

This is as follows.

Under the action of increased centrifugal forces acting on the sensor 8, made, for example, in the form of a massive rod, overcomes the moment of twisting of the elastic element 11, detaches from the limiter 12 and rotates through an angle α. At the same time, it leaves the initial position and the flap 6 is connected, connected with the sensor 8 through the kinematic communication unit (in Figs. 1-4, this is shaft 7).

The angle β of rotation of the shield is k · α, where k is the multiplication coefficient of the kinematic coupling unit (for the rotor in Figs. 1-4, the coefficient k = 1).

With an increase in the angle of rotation of the shield, the aerodynamic resistance of the rotor increases and the frequency of its rotation stops.

With the elimination of the reasons that caused the excess rotor speed above n _p , the elastic element 11 returns the sensor 8 and the brake flap 6 to its original state.

As shown by the calculations, confirmed experimentally, the torque developed by the sensor 8 does not depend on its distance from the axis of the shaft 2, but is determined by the value (α ₀ + α) of the angle of inclination and the angular speed of rotation of the rotor. Therefore, the movement of the sensor from the peripheral region of the rotor, where it is installed in the prototype, to the Central region does not cause a decrease in the moment transmitted from the sensor 8 to the shield 6. However, this eliminates the shadowing of the rotary blade by the sensor, reduces the losses introduced by the aerodynamic resistance of the sensor itself and, therefore, increases the efficiency of the wind turbine.

The installation of the sensor with the deviation of its axis from the plane of the brake flap 6 at an angle of (90-α ₀ ) degrees allows for a horizontal initial position of the flap 6 to obtain the initial inclination of the sensor relative to the axis of the shaft 2, equal to α ₀ degrees. This initial slope in the presence of the corresponding prestressing of the elastic element allows for timely deflection of the brake flap 6 when the speed exceeds the nominal value of n _p .

The implementation of the kinematic communication unit in the form of a multiplier makes it possible to choose the optimal correspondence between the angle (α ₀ + α) of the inclination of the sensor 8 and the angle β of the deflection of the shield 6. This allows for effective braking of the rotor with a smaller excess of its rotational speed over n _p , as well as with a smaller area of the brake flaps 6. Reducing the area of the brake flaps allows you to reduce aerodynamic losses on them before the start of braking.

Claims (15)

1. An orthogonal rotor of a wind turbine, comprising a rotation shaft intended for installation in at least one support of the wind turbine, and at least one bracket fixed to the rotation shaft and provided with a brake flap, on which a wing-shaped rotary blade is rigidly fixed parallel to the rotation shaft, while the brake flap through the kinematic communication unit is connected to the angular velocity sensor and through an elastic element is connected to the rotor construction element, which is stationary relative to the rotation shaft. 2. The rotor according to claim 1, in which the angular velocity sensor is installed with a deviation of its axis from the plane of the brake flap by 70-90 °, and the elastic element is pre-stressed by an additionally introduced displacement limiter. 3. The rotor according to claim 1, in which the bracket is double-console, while the brake flap is placed on the main console of the bracket, and the angular velocity sensor is located on its additional shortened console. 4. The rotor according to claim 1, in which the kinematic communication unit is made in the form of a rotation shaft. 5. The rotor according to claim 1, in which the kinematic communication unit is made in the form of a multiplier, while the angular velocity sensor is located on a low-speed shaft, and the brake flap is located on a high-speed multiplier shaft. 6. The rotor according to claim 5, in which the transmission coefficient of the multiplier is in the range of 2-5. 7. The rotor according to claim 5, in which the multiplier is made on the basis of a gear or chain transmission. 8. The rotor according to claim 5, in which the multiplier is made on the basis of a lever-articulated mechanism. 9. The rotor according to claim 1, in which the kinematic communication unit contains a common element connecting all the brake flaps. 10. The rotor according to claim 1 or 2, in which the elastic element is made in the form of at least one torsion bar located in the cavity of the kinematic communication unit. 11. The rotor according to claim 1 or 2, in which the elastic element is made in the form of at least one torsion spring, covering the shaft of the kinematic communication unit. 12. The rotor according to claim 1 or 2, in which the elastic element is made in the form of at least one torsion bar and kinematically connected with it at least one torsion spring. 13. The rotor according to claim 1, in which the angular velocity sensor is placed in a hollow hub made on the shaft of rotation. 14. The rotor according to claim 1, in which the angular velocity sensor is placed on the bracket. 15. The rotor according to claim 1, in which the angular velocity sensor is placed in a cavity made in a rotating blade.

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