WO2009116961A1

WO2009116961A1 - Multiblade windmill rotor with aerodynamic external and intermediate rings

Info

Publication number: WO2009116961A1
Application number: PCT/UA2009/000004
Authority: WO
Inventors: Евгений ИОСИМОВ
Original assignee: Izosimov Ievgen
Priority date: 2008-03-20
Filing date: 2009-01-29
Publication date: 2009-09-24
Also published as: UA88976C2

Abstract

The invention relates to the variant of the structural design of a windmill rotor for high-power wind-power stations. The rotor has an axis of rotation which is parallel to the wind flow and consists of 6-16 radially positioned blades with controllable setting angles and intermediate and outer rings. The blades and rings are shaped in the form of a wing exhibiting a high aerodynamic quality. The ends of the blades are movably attached to the rings, thereby making it possible to modify the setting angles thereof. The rings receives a partion of wind load from the blades and, in addition the outer ring eleiminates end losses. The invention makes it possible to achieve the coefficient of wind power use up to 60% within the wind speed ranging from 4 to 18 m/sec, thereby increasing by 2-3 times the annual wing energy harvestand, and to increase the rotor diameter up to 300 m.

Description

DESCRIPTION OF THE INVENTION. RUBRIC INDEX MPK-8: FЗD 1/06

MULTI-FASTED ROTOR OF A WIND MOTOR WITH EXTERNAL AND PROMOTIONAL SCIN (AND) RINGS OF AERODYNAMIC FORM.

FIELD OF TECHNOLOGY. The invention relates to wind energy and is a construction of a very powerful rotor of a wind turbine designed for wind power plants.

BACKGROUND OF THE INVENTION Analogs of the invention are powerful wind turbines with an axis of rotation parallel to the wind flow, radially arranged blades with adjustable installation angles with a cross section in the form of an aerodynamic shape profile:

1. Traditional 3-lobed, commercially available by such leading world wind energy companies as РРёвег (model 5M), Multibrid (model M5000), Epegsop (models E-112, E-126), Vestas (models VlOO, V 120), Gepegal Еlestris (model GE / 3.6), Siemeps (model SWT-3.6-107) and others. Information on models can be found on the websites of these companies: www.rerowеr.de; www.multibrid.com; www.enercon.de; www.vestas.sot; www.geroveg.sot; www.rovergepegtiop.sieteps.sot.

2. My invention JV »UA 84360 dated 10.10.2008, (JVs application a 2007 02147 dated 02.28.2007) - A multi-blade rotor of a wind turbine with an outer ring of aerodynamic shape, also described in www.windgoto.info / full_agt_gu and www.wiprotrot. ipfo / frart art ru.

Analogs 1 have:

1. 3 blades with a relative thickness varying along the length of the blade from 10 - 15% at the narrow end to 40 - 45% in a wide part located closer to the center of the rotor.

2. The speed of movement of the ends of the blades at a wind speed of 12 m / s, which is in the range of 80 - 100 m / s.

3. The initial wind speed (wind speed of turning on the generator), which is 3 - 4 m / s, the nominal wind speed (wind speed of the generator reaching its rated power) - 12 - 14 m / s, the maximum wind speed (wind speed of turning off the generator) - 21 - 30 m / s.

4. In the range of wind speeds from initial to nominal, the average coefficient of use of wind energy (Cp) for different models is in the range of 35 - 45%. 5. The maximum rotor diameters, not exceeding 126 m with a mass of the blade 15 - 25 tons. The main disadvantages of 3 - blade rotors:

1. The difficulty is to significantly increase the size of existing rotors, because the cost of the turbine due to the increase in the weight of the blades and their cost will increase much more than the increase in added energy, and the aerodynamic quality will deteriorate.

2. Relatively low Cp. It decreases in the outer (end) part of the blade due to inductive, so-called end losses, as well as due to large profile losses (loss of friction of the blade against the air) caused by the high speed of movement of the ends of the blades. In the part of the blade located closer to the center, the speed of movement of the blades is lower, but the relative thickness of the blade, which is necessary for sufficient strength, is higher. The large thickness also reduces the aerodynamic quality of the blade and significantly reduces Cp.

3. Inefficient use of powerful winds. Wind speeds above 12-14 m / s are still frequent, and the power of the rotor is already limited, a fairly large part of the energy is lost. First of all, a significant increase in the wind load on the blades prevents the increase of the rated power. To make the blades more durable without impairing the aerodynamic quality and significantly increasing their cost is almost impossible.

Analog 2 is a multi-blade rotor with an axis of rotation parallel to the wind flow, radially arranged blades, the ends of which are movably connected to a strong outer ring. The blades have the shape of a wing with high aerodynamic quality, the necessary twist and the ability to adjust the installation angle optimal for the corresponding wind speed, similar to analogues 1. The outer ring has a cross section in the form of an aerodynamic shape profile (can be either symmetrical or asymmetric) with a chord parallel to the air flow . The outer ring, in order to simplify and reduce the cost of its manufacture, transportation and installation, consists of separately made and rigidly fastened segments during installation.

The outer ring is strengthened by spars, ribs and a strong shell or only a strong shell (without spars) in order to redistribute the wind load mainly from the blades to the outer ring. This redistribution occurs due to the fact that the ring does not allow the blades to bend from strong winds, like the rim and spokes of a bicycle wheel. Moreover, the wind load on the blade does not bending force, and pulling. Due to the fact that tearing the blade is more difficult than breaking, it can be made thinner (the maximum relative thickness can be no more than 25 - 30%), significantly improving aerodynamic quality, and cheaper by reducing the shell thickness and using less expensive materials (for example, fiberglass instead of carbon fiber) even with a significant increase in wind speed.

An increase in the number of blades (ranging from 6 to 16, optimally 8 - 9) is necessary, firstly, to more evenly distribute the load on the outer ring, and secondly, to reduce the optimal peripheral speed of the blades, in order to reduce profile losses and increase Cp. When the number of blades is less than 6, the ring is loaded unevenly, which leads to the need to make it too strong and stiff, and therefore too heavy. This will add load to the blades instead of reducing it. The number of blades over 16 will be superfluous, since the uniformity of the load on the ring is already sufficient. The outer ring also eliminates inductive losses and stabilizes the blades (primarily, reduces the likelihood of flutter).

Analog 2 has much better characteristics and capabilities compared to traditional 3-bladed wind rotors. Aerodynamic calculations for a rotor with a diameter of 120 m, the number of blades equal to 8, an outer ring 1.5 m wide, 0.3 m thick and a nominal wind speed of 18 m / s show:

1. The optimal speed of movement of the ends of the blades is 74 m / s at a wind speed of 12 m / s and 94 m / s at a wind speed of 18 m / s.

2. Due to the reduction of profile losses, due to the reduction of the peripheral speed and relative thickness of the blades, as well as the elimination of the end losses, Cp was achieved in excess of 60% in the range of wind speeds from initial to nominal.

3. Due to an increase in the nominal wind speed and Cp, the rated power was increased from 4.5 MW (for analogues 1 with a rotor diameter of 120 m) to 20 MW. Maximum wind speed increased to 35 m / s.

4. The calculation of the total annual electricity collection shows an increase of 2 to 3 times, depending on the wind class of the installation location of the wind unit.

5. There was an opportunity to increase the maximum rotor dimensions from existing ones, with a diameter of 120 - 126 m, to diameters of 250 - 300 m.

6. Due to the redistribution of part of the load from the blades to the outer ring, the ability to reduce the cost of production, delivery and installation makes it easier to divide the blades into several components with assembly during installation of the rotor. The disadvantages of analogue 2:

1. The cost of construction at all stages - production, delivery, installation and maintenance due to the larger number of blades, the outer ring, increased generator power and greater congestion of the tower even with a significant reduction in the cost of each blade.

2. Additional difficulties in the installation of the rotor, due to the fact that while the ring is not assembled, long blades, including in the horizontal position, must withstand their own weight and the weight of the ring segments attached to their ends.

SUMMARY OF THE INVENTION The main tasks solved by the invention:

1. Further reduction of the load on the outer ring and on the blades, especially at the stage of installation of the rotor.

2. Improving stabilization of the middle parts of the blades without hardening of the blades, which is most important for rotors with diameters of more than 150 - 200 m with increased nominal wind speeds.

The problems are solved by using at least one intermediate ring in the multi-vane rotor with the outer ring (analog 2), similar to the outer ring. The intermediate rings divide the blades into external and internal parts, they have the appearance of a wing with high aerodynamic quality with a chord parallel to the air flow. By parallelism here and in the claims, as well as in analogue 2, we mean the type of construction, and not the exact value of parallelism (the actual inclination of the chords can be in the range of 0 - 20 degrees). It is assumed that for rotors with diameters of 150 - 240 m., One intermediate ring will be sufficient, for diameters of 250 - 300 m - two. All rings, as well as the outer ring of analogue 2, consist of separate segments connected during installation. For unification, they can be the same, and their number can be a multiple of the number of blades.

In the following, a variant with one intermediate ring will be described. The option with two or more intermediate rings is completely similar.

Reducing the load on the blade and on the outer ring will occur due to the fact that the intermediate ring will take on part of the load from the inner part of the blade, similar to the redistribution of the load by the outer ring in analogue 2. The load on the outer ring will only be due to the outer part of the blade. Also, stabilization of the middle parts of the blades will occur, which will allow not to increase the thickness of their shells and the thickness of their spars (if any) to ensure rigidity. The connection of the parts of the blades between themselves is carried out using an intermediate ring located between them, and can be either rigid or adjustable. The fastening of the parts of the blade to the rings, as in analogue 2, is movable and can be carried out in six versions:

1. Fixation of the shaft part extending from the end of the shaft blade, for example, the end of the spar, in the bearing of the sleeve located in the ring and fixed to its spar (there can be several spars of the ring) or for ribs (in the absence of the spar of the ring).

2. By fixing the shafts fixed in the ring in the bearings of the bushings located at the ends of the parts of the blades.

3. By fixing the threaded rods emerging from the ends of the parts of the blades with nuts in the splines of the short shafts of the bushes located in the rings, similar to the fastening of the root parts of the blades to the central hub of the rotor.

4. Fixing the threaded rods emerging from the short shafts of the sleeve rings, nuts in the splines of the ends of the parts of the blades.

5. Fixing the threaded rods emerging from the shafts of the bushings of the ends of the parts of the blades, nuts in the splines of the rings.

6. Fixing the threaded rods emerging from the rings, nuts in the splines of the shafts of the bushings of the ends of the parts of the blades.

These mounting options allow you to freely change the installation angles of the blades depending on the specific wind speed. Mounting options may require a forced rotation of the outer part of the blade. The transmission of torque to one shaft of the sleeve relative to the other shaft (or torque from the sleeve to the shaft) can be carried out, for example, by gear transmission either from an electric motor or by means of mechanical traction from a rotation device located in the central rotor sleeve.

The device for forced rotation of the outer part of the blade will further reduce the load on the outer ring and on the outer part of the blade due to the maximum load for the inner part of the blade at wind speeds above nominal, which is desirable due to the narrower and thinner parts of the blades. In addition, it makes no sense to rotate the entire blade if it is enough to rotate only the narrow outer part. The resulting uneven load on the blade will give a result only if there is an intermediate ring stabilizing the middle part of the blade. In order to reduce inductive losses, as in analogue 2, the gap between the parts of the blades and the rings should not be large and should be in the range of 0.5 - 10 cm (optimally 1 - 2 cm). Due to temperature (seasonal) small changes in the size of the rotor within a small range, the taper of the rotor will change. The shafts of the fastening parts of the blades and rings must be hollow for the passage of a lightning rod connecting the metallized strip of the outer part of the outer ring to the central rotor hub, and the wires of the device for adjusting the installation angles of the outer part of the blade (if any). The presence of an intermediate ring will not worsen the aerodynamic and improve the strength (and, therefore, weight and cost) qualities of the rotor with a diameter of more than 120 - 150 m, therefore, the above parameters and advantages of analogue 2 will be preserved for the rotor proposed in the invention.

BRIEF DESCRIPTION OF THE DRAWINGS. In FIG. 1 shows a general view of a rotor having 8 blades, an intermediate and an outer ring. In FIG. Figures 2 and 3 show a fragment of the rotor showing a variant of connecting the parts of the blade to each other and with the intermediate ring sleeve, in which the shafts of the parts of the blades are inserted one into the other and there is no separate adjustment of the installation angles of the outer part of the blade. In FIG. 4 and 5, a fragment of the rotor is shown, showing a variant of connecting the shaft of the end of the outer part of the blade with the sleeve of the outer ring, in which the outer ring contains 2 spars of circular cross section and there is no device for turning the end of the blade. FIG. 2 and 4 show a sectional connection in the plane of rotation of the rotor. FIG. 3 and 5 show a connection in section perpendicular to the plane of rotation of the rotor.

The numbers in the figures of FIG. 1 to 5 are indicated:

1. the outer part of the blade;

2. the inner part of the blade;

3. outer ring;

4. intermediate ring;

5. blade rib;

6. rib of the ring;

7. The sleeve of the intermediate ring as part of the rib;

8. bearing (must be closed type and designed for a long service life without additional lubrication); 9. a nut-clamp of an internal ring of the bearing;

10. washer-retainer of the outer ring of the bearing;

11. external docking shaft;

12. internal docking shaft;

13. screws securing the shaft to the rib of the blade;

14. connecting bolts for fixing the shafts to each other;

15. technological hatch openings for access to internal parts during installation of the structure;

16. The connecting shaft for the outer ring;

17. side members of the outer ring;

18. sleeve of the outer ring.

Instead of the connecting bolts 14, rings and studs inserted into the grooves between the connecting shafts can be used. The spar in the blade may be, may be absent or only at its end for rigid fixation in the blade of the shaft emerging from the end of the blade. There are many other mounting methods that can be used to implement the proposed design, including with the ability to adjust the installation angles of the parts of the blades. The drawings are shown for illustrative purposes only and as an option to prove its feasibility.

INDUSTRIAL APPLICABILITY. The technologies for the manufacture, transportation and installation of rotor blades have already been established in analogues 1 and differ only in a change in their shape and an increase in their number. The manufacture and transportation of individual ring sectors are carried out similarly to blades. Moreover, for the manufacture of segments of rings, blades, ribs and spars (if any), a multilayer sheath of fiberglass layers filled with epoxy or polyester glue can be used. The manufacture of bushings and shafts of rings and blades is also not difficult. The interconnection of the segments of the rings is carried out by connecting the spars (if any), for example, by a longitudinally detachable coupling, and screw (or screws) connecting the shells with strong internal overlays or wide ribs. To access the inner part of the ring or blade, you can use technological hatch holes (for example, rectangular), made (at the production stage) by cutting a portion of the shell of the ring or blade. Subsequently, these sections of the shell are fixed with screws (or screws) in the hatch holes to the overlays installed from the inside, and the resulting gaps are sealed with sealant. The rotor can be mounted using either a high crane or a small crane mounted on a special platform that can move vertically along the tower of a turbine under construction (most promising).

When mounting the rotor, first the internal parts of the blades are attached to the generator shaft sleeve mounted on the tower, as are the analogues 1. After that, the segments of the intermediate ring are alternately attached to the ends of the blades from the platform fixed to the tower or raised by a crane and fastened to each other, periodically turning to do this generator shaft. Then, the outer parts of the blades are attached to the finished intermediate ring and the inner parts of the blades. After that, the segments of the outer ring are likewise fastened and connected to each other.

As a result, all operations on the manufacture, transportation, installation and operation of the rotor are not very difficult and technically feasible.

Claims

CLAIM.

A wind turbine rotor that converts the energy of the wind flow into the energy of rotation of the shaft of the electric generator, with the axis of rotation parallel to the wind flow, radially arranged blades with adjustable installation angles having the necessary twist, with a section in the form of an aerodynamic shape profile, the number of blades from 6 to 16, with an outer ring movably attached to the ends of the blades, with a cross section in the form of an aerodynamic shape profile with a chord parallel to the air flow, reinforced in order to receive part of the load from the blades characterized by the presence of at least one intermediate ring dividing the blades into parts, movably attached to the parts of the blades, with a section in the form of an aerodynamic shape profile with a chord parallel to the air flow, consisting of segments rigidly fastened to each other.