RU2644799C1 - Cascade wind generator - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to wind power engineering. Cascade wind generator comprises at least an inclined air duct of a cylindrical shape, in the lower part of which a heater is installed, a horizontally located air duct is connected to the upper part of said air duct by means of a curved adapter, consisting of lengths of cylindrical tubes of various diameters, connected with the possibility of forcing the air flow through a reduction in the duct section, Inside the horizontal duct, at least two axial turbines are installed coaxially with it, each of which is connected to its electric generator.

EFFECT: invention is aimed at increasing power of wind generator.

8 cl, 1 dwg

Description

The invention relates to the field of energy, namely alternative energy, and can be used to generate electrical energy, preferably in hot, sunny climates and mountainous terrain, where there are mountainsides with a drop in temperature and air pressure in height.

A known project is a wind farm (US patent 4187686, publ. 12.02.1980). According to a well-known project, two parallel pipes filled with gas are placed along the steep slope of the mountain. At the top and bottom, the pipes are interconnected by horizontal pipe segments, forming a closed system of communicating vessels, isolated from the external atmosphere. A wind turbine with an electric generator is located in the lower horizontal part of the system. Hot water is injected into the lower part of one pipe, and cold water is injected into the upper part of the other pipe, the resulting temperature difference in the pipes causes gas to move in the system according to the rule of communicating vessels and the resulting gas flow rotates the wind turbine.

Significant disadvantages of this design of stations include the fact that due to the low speed of free lowering of a cold column of air, a sufficiently high value of the kinetic energy of air masses cannot be realized, and therefore the power and efficiency of such stations are small.

Known (patent RU 2444645, published September 30, 2009) is a mountain air-traction power plant, comprising a vertical duct communicated by its entrance from the lower side and exit from the upper side with the atmosphere, an air motor installed in it kinematically connected to an electric generator, and a duct entrance communication channel with the atmosphere with an air heater in it. The duct is made in the form of a mine working isolated from the entry of underground water, the mouth of which on the earth's surface is the outlet of the duct, the heater is a geothermal reservoir, represented by dry warm (or hot) rocks, characterized by induced or naturally reported fracture, communicated with the entrance of the mine , the channel of communication of the duct inlet with the atmosphere is the geothermal collector itself, which extends to the intersection with the relief surface of the mountainous area, or the bottom is an additional mine or several additional mine workings constructed from the surface to the geothermal reservoir and located around the mine, with a slide installed at the mouth of the mine; the power plant is equipped with an inducer of air movement, for example a fan, in a mine.

A disadvantage of the known power plant should be recognized as too narrow a scope due to the use of mining with a geothermal reservoir.

Known (patent RU 160736, publ. 03/27/2016) a wind turbine comprising a housing mounted on a vertical mast with the possibility of rotation around its longitudinal axis, blade-type wind turbines with a horizontal axis of rotation, kinematically connected with electric generators connected to a common electrical load. The housing is made in the form of a cylindrical pipe, inside of which a turbine shaft with at least two bladed wind turbines mounted on it along the shaft axis is located on the bearing bearings, and motionless driving sun gears are fixed at both ends of the shaft cantilever protruding from the bearings, made double-crowned with an external tooth, engaged with driven gears of the drive of electric generators, installed in pairs evenly in a circle on the outer surface of the pipe, from the side of both of its ends, m number of teeth of the sun gear on the leading greater than the number of teeth of the driven gear wheel drive the power generator, wherein the pipe fastening place to the mast is shifted to one of the pipe ends.

The known device operates as follows. Under pressure from the wind on the side surface of the body, the latter, due to the displacement of the attachment point to one of the pipe ends, like a weather vane, rotates around the mast axis, being installed to the wind by the pipe end. After that, the wind rotates the blades of the wind turbines mounted on one turbine shaft, creating a torque on it, which is summed up on the sun gears made by two-crowned ones. The driven gears of the electric generator drive are arranged at regular intervals around the leading sun gear. The number of teeth on each of the driven gears is less than the number of teeth on the rims of the sun gears, and therefore the rotation of the driven gear is transmitted to the generator with an increased speed, which leads to an increase in efficiency.

The main disadvantage of this device is a sharp narrowing of its scope, since connecting a large number of power generators to one turbine shaft leads to the fact that this device works stably only at high wind speeds. He will have a large moment of starting, as a result, it is inoperative at low wind speeds.

The known technical solution is made as the closest analogue.

The technical problem to be solved using the developed design is to develop a new type of environmentally friendly power plant.

The technical result of the invention is to increase the power of the wind generator by additionally installing N axial turbines in the duct, each of which is connected to its own electric generator, and forcing the air flow.

To achieve the specified technical result, it is proposed to use a cascade wind generator of a developed design. The developed wind generator comprises at least a cylindrical inclined duct, a heater is installed in the lower part, and a horizontally arranged duct is connected to the upper part of the specified duct through a curved adapter, consisting of pipe sections of various cylindrical shapes, connected with the possibility of forcing the air flow by reducing duct section, at least two axial turbines are installed coaxially with the inside of the horizontal duct Each of which is connected to its own power generator.

At the entrance to the inclined duct, an accumulator / radiator can be additionally installed, the output of which for the air masses is in communication with the internal volume of the inclined duct.

A solar collector can be installed on the surface of the storage / radiator with the possibility of heating the air masses inside the storage.

A block of solar photovoltaic cells connected to electric heaters installed inside the drive / radiator can be installed on the surface of the duct.

Inside the drive / radiator, heating elements can be installed connected to the output of the heat generator.

At the outlet of the horizontal duct, an element can additionally be installed to prevent aerodynamic noise.

Preferably, the horizontal duct further comprises at least two sections forcing the air masses, each of which is installed in front of the turbine.

Typically, a bent adapter is made with a bend radius not less than five times the diameter of the inclined duct.

The basis of the cascade wind generator is the presence of an air duct of variable cross section. Moreover, the first section of the duct is located on the side of a mountain and serves for preliminary dispersal of air masses. To increase and maintain traction in the lower part of the inclined duct, it is possible to additionally use a heater of any type. The second section of the duct is located horizontally and is designed to generate electricity. It contains axial-type turbines with a number of at least two.

The axis of rotation of the turbines coincides with the axis of symmetry of the duct. Turbines through gearboxes are each connected to its own generator. The air flow enters the blades of the first turbine, additionally accelerating due to the narrowing of the duct. Moreover, the air at the outlet of each previous turbine, once again further dispersed by reducing the cross section of the duct, enters the inlet of the next turbine.

The number of turbines and, accordingly, the number of stages of the wind generator is limited by the minimum possible cross-section of the duct.

The figure shows the design of the developed cascade wind generator in the preferred form of implementation. The wind generator comprises an inclined duct 1, a storage / radiator 2, a solar thermal collector 3, a solar photovoltaic battery block 4, heating elements 5, a heat generator operating on any type of gaseous, liquid or solid fuel (not shown), via an adapter 6 an additionally connected horizontal section duct 7, comprising a first 8 section narrowing the pipeline section, a first turbine 9, a reducer of the first turbine 10, a first generator 11, a second 12 pipe section narrowing the section, W Rui turbine 13, second turbine gear 14, the second oscillator 15, n-th diffuser 16, n-th turbine 17, reducer n-th turbine 18, n-th generator 19, element 20, prevents aerodynamic noise.

The operation of a cascade wind generator is based on the use of kinetic energy of air movement in an insulated duct. The movement of air occurs due to the difference in pressure and temperature at the opposite ends of the duct 1, located on a slope of mountainous terrain. The greater the difference in air density, the greater the speed of movement of air masses in the duct, respectively, the greater the power of the installation. To enhance the effect, part of the atmospheric air enters the accumulator / radiator 2 for heating the air masses, where they are heated using a thermal solar collector 3 based on panels with a high absorption capacity of solar heat mounted on the outside of the accumulator. The drive / reactor 2 is a box. In addition, the air in the storage / radiator is additionally heated using heating elements 5, powered by a solar photovoltaic battery 4 located on the outside of the duct 1. The storage / radiator has the ability to heat the air not only on the basis of direct sunlight, but also from heat generators working on any kind of solid, liquid or gaseous fuel. This solution allows you to get electricity in the dark and not depend on weather conditions.

If the entire duct is made oblique, then part of the kinetic energy of the air masses will not be spent on generating electricity, but on the task of raising the mass of air to a certain height, depending on the difference in height of the beginning and end of the duct. To increase the efficiency of the wind generator, the second section of the duct where the turbines are located is made horizontal. Moreover, the inclined and horizontal sections of the duct are connected using an adapter 6, the radius of which to reduce the coefficient of local resistance must be at least five times the diameter of the inclined duct.

Wind power, i.e. the amount of energy that can be generated using the kinetic energy of air movement is determined by the expression:

Where

q is the density of air in kg / m ³ ;

S is the cross-sectional area of the duct in m ² ;

V is the air velocity in m / s.

From formula (1) it follows that the power depends on the cube of the speed of movement of air masses.

Therefore, before coming into contact with the blades of the first turbine 9, the air masses force, i.e. accelerate to a speed of V ₁ , due to the narrowing of the horizontal part of the duct 7.

The narrowing is done smoothly using a conical first narrowing section of the pipeline section 8.

According to the Bernoulli equation for a horizontal pipe section:

Where

V ₀ - air velocity in the duct section with a cross section S ₀ vm / s ² ;

q is the density of air in kg / m ³ ;

P _o - static air pressure in the section with a section S ₀ vn / m ² ;

V ₁ - air velocity in the section with the cross-section S1в m / s;

P ₁ - static air pressure in the section with a section S1vn / m ² ;

- динамическое давление или скоростной напор вн/м².

- dynamic pressure or velocity head vn / m ² .

Bernoulli's law states that an increase in air velocity (dynamic pressure) in a section of a duct with a smaller cross section occurs due to a decrease in static pressure in a section of a duct with a larger cross section, but in total the static and dynamic pressures are constant.

According to the continuity equation:

Where

S ₀ - the cross-sectional area of the duct in the area with a large diameter vm ² ;

V ₀ - air velocity in the duct section with a large diameter in m / s;

S ₁ - the cross-sectional area of the duct in the area with a smaller diameter vm ² ;

V ₁ - air velocity in the duct section with a smaller diameter in m / s.

Then:

those. air velocity increases in direct proportion to the decrease in the cross-sectional area of the duct.

Having previously dispersed in section 8 narrowing the pipeline section, the air enters the blades of the first turbine 9. The turbine is a multi-blade wind wheel made according to the scheme of an axial aviation turbine. Moreover, the turbine blades are located on the periphery of the wind wheel, where they work most efficiently. The central part of the turbine remains free for the movement of air masses and creates minimal resistance to their movement.

The turbine is used to convert the kinetic energy of the air masses into torque, which is transmitted to the electric energy generator 11 using a gearbox 10.

Passing through the turbine blades, the air is not completely braked, since the maximum wind utilization factor is 0.593 (Betz criterion), but to a speed of V ₁₁ .

Mixing with the air coming through the central part of the turbine, the air at the outlet of the first turbine will have a total speed V ₂ [4]:

where m ₂ is the mass of air passing through the turbine blades, in kg;

V ₁₁ - the speed of the air passing through the turbine blades, in m / s;

m ₁ is the mass of air passing through the center of the turbine, VCG;

V ₁ is the speed of air passing through the center of the turbine, in m / s;

V ₂ is the total velocity of all air after mixing in m / s.

Further, the air flow again accelerates to the initial speed V ₁ . To this end, the cross-section of the duct using the second narrowing section of the pipeline section 12 is reduced to section S ₂ . Since after the passage of the blades of the first turbine 9, the air flow rate in the duct section with section S ₁ decreased to V ₂ , we have the ratio:

This implies:

Therefore, the cross section of the duct must be reduced before the second turbine 13 in V ₂ / V ₁ times. After the acceleration of air in section 12, it enters the blades of the second axial turbine 13, the output power of which will be S ₁ / S ₂ times less than in the first. The turbine 13 using a gearbox 14 drives the generator 15.

Since the kinetic energy of the air masses on the second turbine was also not completely converted to the generator torque, the air at the output of the second turbine can be fed to the inlet of the third turbine, after having forced it by reducing the cross section of the duct. On the third turbine, the power of the generated electricity will naturally be less than the second by S ₂ / S ₃ times, where S ₃ is the section of the duct in the area where the third turbine is located. The entire procedure described above can be repeated n times until the duct section is reduced to a reasonable extent.

In the last section of the horizontal duct, the nth narrowing section of the pipeline section 16, the nth turbine 17, the nth gearbox 18 and the nth generator 19 will be located.

To prevent aerodynamic noise, the duct terminates in section 20.

Naturally, the result of the scheme described above is an increase in the total power of the entire installation.

The device is easily implemented at the present stage of development of science and technology. As a generator, you can take any type of generator: permanent magnets, asynchronous, valve. So, the output power of the generators will lie in the range from tens to hundreds of kilowatts, then it will not be difficult to select the generators of the required power.

The air duct is installed on a hillside on foundation supports, which are metal pins driven into the ground with weld-in lodges, which surround the duct along the outer diameter. The duct is assembled from pieces of lightweight pipes made of plastic (for example, polycarbonate) with minimal roughness on the inside to reduce friction during air movement. The air duct is fixed in the cradles during installation with screws. Pipe segments are joined end-to-end and fixed with tightening clamps. The duct sections where the constrictions, turbines and gears are located are made of any suitable metal, such as aluminum.

Claims (8)

1. A cascade wind generator, characterized in that it contains at least an inclined cylindrical duct, a heater is installed in its lower part, a horizontally located duct consisting of pipe sections of cylindrical shapes of various diameters is connected to the upper part of the specified duct using a curved adapter, connected with the possibility of forcing the air flow by reducing the cross-section of the duct, at least m are installed coaxially with the inside of the horizontal duct Here, two axial turbines, each of which is connected to its own electric generator. 2. The wind generator according to claim 1, characterized in that an accumulator / radiator is additionally installed at the entrance to the inclined duct, the output of which for the air masses is in communication with the internal volume of the inclined duct. 3. The wind generator according to claim 2, characterized in that a solar collector is installed on the surface of the storage / radiator with the possibility of heating the inside of the storage of air masses. 4. The wind generator according to claim 2, characterized in that a block of solar photovoltaic elements connected to electric heaters installed inside the drive / radiator is installed on the surface of the duct. 5. The wind generator according to claim 2, characterized in that heating elements connected to the output of the heat generator are installed inside the drive / radiator. 6. The wind generator according to claim 1, characterized in that at the output of the horizontal duct an additional element is installed that prevents aerodynamic noise. 7. The wind generator according to claim 1, characterized in that the horizontal duct further comprises at least two sections forcing the air masses, each of which is installed in front of the turbine. 8. The wind generator according to claim 1, characterized in that the curved adapter is made with a bend radius not less than five times the diameter of the inclined duct.

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