RU2463473C1 - Vane-sail wind power plant - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: vane-sail wind power plant comprises a rotary platform, which carries stands, where a vane-sail windwheel is installed as capable of free rotation in the form of a shaft, at the ends of which there are front and rear swings installed, which carry blades rigidly fixed on them. The front swing facing wind is arranged in the form of a tubular cross, the opposite rear swing is arranged in the form of a square tubular frame, ribs of which are rigidly and perpendicularly fixed with the middle part at the free ends of the tubular cross identical to the front cross. Blades are arranged in the form of rectangular plates from a thin-sheet or fabric material and are rigidly fixed by one of faces on tubes of the front swing and by the opposite face - on appropriate halves of external ribs of the rear swing frame, parallel to tubes of the front swing.

EFFECT: invention with simplicity and manufacturability provides for reduction of windwheel dimensions, which makes it possible to install it on roofs of residential and industrial buildings.

2 dwg

Description

The invention relates to wind energy, and in particular to a device for wind wheels of wind power plants (wind turbines) of small and medium power, including for installation on the roofs of residential buildings and industrial buildings.

A wind power installation is known, the wind wheel of which is made in the form of an impeller with three or four blades [1], (pp. 111 and 127), rigidly fixed to one end of the power shaft, the other end of which is connected to the actuator, for example by means of an elastic coupling.

Such a design of the known technical solution ensures the simplicity of the design of the winged wind wheel and high revolutions of the power shaft, which, when properly balanced, reduces the level of vibration to a minimum and allows the installation of wind turbines on the roofs of industrial buildings, but on the roofs of residential buildings they do not pass by noise level created by dissecting parts of the air flow in the inter-blade space.

But no less significant drawback of wind turbines with winged wind wheels is their extremely low coefficient of use of wind energy. Since at present there is an arbitrary interpretation of this criterion for comparing various structural schemes of wind wheels, it is necessary to provide the following explanations.

This criterion was first formulated and put into circulation by engineer V.P. Vetchinkin. in 1914, and in 1920, professor Zhukovsky N.E. concluded the utilization of wind energy by an ideal windmill, referring to a wind wheel, in which: "... - the axis of rotation is parallel to the wind speed vector;

- an infinitely large number of blades of very small width;

- the profile resistance of the wings is zero, and the circulation along the blade is constant;

- the lost speed of the air flow on the wind wheel is constant over the entire swept surface of the wind turbine;

“The angular speed of the wind wheel is tending to infinity.”

Given these assumptions, according to N.E. Zhukovsky, V.P. Vetchinkin and E.M. Fateev, the formula for determining the ideal coefficient of utilization of wind energy ξ should be:

where P is the frontal pressure of the air flow on the blades of the wind wheel;

V is the speed of the working stream of the air flow;

V ₁ - the same in the plane of the wind wheel;

F is the area of the working jet swept by the wind wheel;

ρ is the density of the air flow.

After transformations, equation (66) takes the form:

Obviously, the value of P in equation (66a) is that part of the total pressure of the wind flow that falls on the projection of a body of arbitrary shape onto a plane perpendicular to the direction of the wind, while it is called the mid-section and denoted by F ₁ , and the pressure value attributable to mid-section, called frontal pressure and denoted by P _x .

A known equation for determining the value of P _x , which is presented in the form:

Substituting (41) into (66a) after the transformations, we obtain:

where C _x - drag coefficient (determined according to table 2 [1], p. 49);

,

,

Substituting the above notation into formula (15), we obtain the final universal formula for determining the numerical value of the coefficient of utilization of wind energy by any type of wind wheels.

where C _x takes into account the ratio of the length and width of the blades;

To _s - shows what proportion of the surface swept by the windwheel is overlapped by its mid-section, and e - what proportion of the speed of the wind flow is spent on creating torque on the power shaft of the wind wheel.

So at C _x = 1.3; K _s = 0.208 (for a four-blade wind wheel) and e = 0.33

ξ = 1.3 · 0.208 · (1-0.33) = 0.18 max.

A vivid illustration of the arbitrary interpretation of the coefficient of utilization of wind energy is the statement of the doctor of technical sciences Fateeva EM that by observing a number of conditions (explicitly related to vague concepts) this indicator can reach 46% (0.46), (see [1], p. 87), which is not true.

A known rotor of a wind turbine [2], comprising a rotary platform supporting racks on which a sailing wind wheel is mounted with the possibility of free rotation, is made in the form of a shaft, at the ends of which a conical ribbon elastic blade with decreasing radius and pitch of the spiral is fixed, with one of the ends of the spiral is mounted on a sleeve having axial movement along the shaft.

This design of the blade provides a high duty cycle and the corresponding utilization of wind energy, because with this design, the mid-section of the spiral blade is almost identical to the surface swept by the wind wheel and the numerical value of the fill factor is close to unity.

However, the practical implementation of this technical solution is very difficult, because the design of the wind wheel is extremely low-tech and requires special equipment, on the general technological bases of machine-building plants which simply does not exist.

In addition, the necessary rigidity of the spiral tape without continuous rigid attachment to the shaft of the wind wheel with its length of several spiral steps is unattainable, and balancing the wind wheel along its entire length is very difficult.

The claimed object contains a rotary platform, bearing racks, on which a wing-sailing wind wheel is mounted with the possibility of free rotation, made in the form of a shaft, at the ends of which there are front and rear wings, bearing blades rigidly fixed to them. The front swing, facing the wind, is made in the form of a tubular cross, the opposite back swing is made in the form of a square tubular frame, the ribs of which are rigidly fixed with the middle part on the free ends of the tubular cross, identical to the front cross perpendicular to them, and the blades are made in the form of rectangular plates of thin-sheet or fabric material and are rigidly fixed by one of its faces to the tubes of the front Mach and the opposite side - on the corresponding halves of the outer edges of the square tubular p pits rear maha maha parallel tubes of the front.

Technical advantages of the claimed object compared to the prototype are as follows:

- the implementation of the front swing in the form of, for example, a tubular cross, and the rear swing - in the form of a tubular square frame, the middle part of its ribs rigidly fixed to the ends of the tubular cross, identical to the front swing perpendicular to them, makes it possible to make the blades in the form of rectangular plates of thin-sheet or fabric material;

- rigid fastening of the rectangular blades of one of its faces on the front Mach tubes and the opposite side - on the corresponding halves of the outer edges of the square tubular frame of the rear mach, parallel to the front mach tubes, provides a compact mutual arrangement of the blades with minimal inter-blade space between them and different directions of the parts of the wind flow, escaping from the blades into the wheel space.

The combination of the indicated technical advantages of the claimed object in comparison with the prototype provides a technical result consisting in a significant reduction in the length of the wind wheel to 0.25 of the helix pitch of the prototype, which makes it possible to install the claimed object on the roofs of residential buildings and lighting towers of potentially dangerous sections of highways, increasing the manufacturability of the structure by the execution of the blades in the simplest embodiment in the form of rectangular plates of thin-sheet or fabric material, rigidly fastened interconnecting all elements of the wind wheel, as well as in simplifying the technology and improving the quality of its balancing by reducing the total length of the wind wheel.

In the drawings, a wing-sailing wind turbine is schematically illustrated, where in Fig. 1 its projection is shown from the side facing the wind; figure 2 is the same side view. In this case, the straight arrows show the nature of the distribution of wind speed during its interaction with the blades of the wind wheel, where:

V _p - loss of velocity of the wind flow escaping from the blades into the wheel space;

V _km is the fraction of speed that provides the creation of torque on the shaft of the wind wheel.

The arrow arrow shows the direction of movement of the turntable during the self-installation of the wind wheel under the influence of the wind flow in a position perpendicular to it.

The winged-sailing wind power installation (wind turbine) contains a rotary platform 1, carrying racks 2, on which a winged-sailing wind wheel made in the form of a shaft 3 is installed with the possibility of free rotation, at the ends of which a front 4 and a rear 5 flywheel are mounted, bearing rigidly fixed to them blades. Moreover, the front max 4 is facing towards the wind, and the rear max 5 is located on the leeward side. The front max 4 is made in the form of a tubular cross with tubes 6, 7, 8 and 9, and the rear max 5 is made in the form of a tubular cross identical to the front max 4, the free ends of the tubes of which are covered by a square tubular frame, ribs 10, 11, 12 and 13 of which rigidly fixed by the middle part on the free ends of the tubes 6, 7, 8 and 9, identical to the tubular cross perpendicular to them and divided by the attachment points into two equal parts. On the front 4 and rear 5 max, the blades 14, 15, 16 and 17 are rigidly fixed, made in the form of flat rectangular plates of thin sheet or fabric material, which are rigidly fixed by one of their faces to the tubes 6, 7, 8 and 9 of the front mach 4 and the opposite face is also rigidly fixed on the corresponding half of the outer ribs 10, 11, 12 and 13 at an angle of attack α to the direction of the wind, forming rigid bonds 6-10-14, 7-11-15, 8-12-16 and 9-13 -17, which, together with the rigid connections of max 4 and 5 with the shaft 3, forms a rigid structure of a wing-sailing wind wheel Rotating the actuator such as the generator 18 of electric current.

When a wind appears at a speed V _, its flow presses on the blades 14, 15, 16 and 17 at an angle of attack α, while the wind speed on each blade decomposes into components:

V _ld - the speed that creates frontal pressure on the blade, directed perpendicular to its plane, forming torque on the shaft 3;

V _n1 - velocity directed along the plane of the blade and going into zakolesnoe space as a loss, the loss of flow are mutually perpendicular and are in different planes, which eliminates the impact of the flow on a depression zone on the rear side after extending blade and the ram pressure increases.

It's obvious that

However, not all the magnitude of the component V _l goes to the formation of torque, because it is not perpendicular to the shaft 3 of the wind wheel, but forms an angle α with the direction of V _km .

Substituting (18) into (17) and solving the equation for V _km , we obtain equation (19) to determine the fraction of wind speed (V _km ) attributable to the formation of torque on the shaft 3 of the wind wheel.

The torque on the shaft of the wind wheel is determined by the well-known formula:

,

,

where P _km is the circumferential force created by the component V _km of wind speed;

b is the width of the blade.

The value of P _km is determined by the equation:

where C _x - drag coefficient taking into account the shape of the blade. According to table.2 [1], p. 49. C _x = 1.1.

F is the area of the mid-section of the wind wheel.

ρ is the air density of 1.25 kg / m ³ .

Given that the wind wheel under consideration contains 4 blades of length L each, equation (41) takes the form:

Substituting (21) into (20) taking into account (19) after the transformations, we obtain:

To compare the claimed object with the working windmills by the value of the coefficient ξ of use of wind energy, determined by the formula (15), it is necessary to determine the fill factor K _s , which for the structure under consideration is defined as the ratio of the square to the square of a circle with a diameter equal to its diagonal, i.e. . to the area of a circle of a circumscribed circle.

From elementary geometry it is known that this value is 0.65.

Then ξ = 1.1 · 0.65 · (1-0.33) = 0.472.

The result of a comparison of the coefficients of known structures and the claimed object indicates that this parameter for the latter is 2.472 times higher.

Information sources

1. Fateev E.M. Wind turbines and wind turbines. - M .: OGIZ-agricultural, 1948, 185 p.

2. Description of the invention to the USSR author's certificate No. 1638359 of 04/03/89, IPC F03D 1/06 (prototype).

Claims (1)

A wing-sailing wind power installation containing a rotary platform bearing racks on which a wing-sailing wind wheel is mounted with the possibility of free rotation, made in the form of a shaft, at the ends of which a front and rear wings are installed, bearing blades rigidly fixed to them, characterized in that the front swing, facing the wind, is made in the form of a tubular cross, the opposite back swing is made in the form of a square tubular frame, the ribs of which are rigidly fixed with the middle part to the free ends of the tubular cross, identical to the front cross, perpendicular to them, and the blades are made in the form of rectangular plates of thin sheet or fabric material and are rigidly fixed by one of their faces to the tubes of the front swing and the opposite side - on the corresponding halves of the outer edges of the square tubular frame of the back swing, parallel to the front swing tubes.

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