JP2004124926A - Wind power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wind power generator capable of further improving generating efficiency. <P>SOLUTION: The wind power generator comprises a generally cylindrical duct 1 that is generally blade-shaped in a side wall cross-section, a impeller 2 capable of rotating about an axis of the duct 1, and a nacelle 5 structuring a streamlined pencil element 3 with the impeller 2 and storing a generator 4 using rotating force of the impeller 2. The side wall cross-section of the duct 1 is the blade shape capable of generating a decompression area behind the duct 1 and suppressing the generation of a whirl behind the duct 1. A tip end portion of the pencil element 3 is inside of the duct 1, and a rear end portion is projected from a duct 1 rear end portion so as to close to a tip end portion of the decompression area generated behind the duct 1. Blades 21 of the impeller 2 are provided in the maximum wind speed range 13 inside of the duct 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a substantially cylindrical duct having a substantially wing-shaped cross-section of a side wall, an impeller having a plurality of outwardly protruding blades and rotatable around a duct axis, and a streamlined pencil body together with the impeller. And a nacelle accommodating a generator utilizing the rotational force of the impeller.
[0002]
[Prior art]
In view of improving the power generation efficiency by efficiently rotating the impeller, some wind power generators similar to the wind power generator have been proposed (see Japanese Utility Model Application Laid-Open No. 56-74871).
[0003]
[Problems to be solved by the invention]
However, the inventor of the present application has found that there is room for improvement in power generation efficiency by studying the airflow near the wind power generator.
[0004]
Therefore, an object of the present invention is to provide a wind turbine generator capable of further improving the power generation efficiency.
[0005]
[Means for Solving the Problems]
The wind power generator of the present invention for solving the above-mentioned problems has an airfoil shape in which a side wall cross-sectional shape of the duct has an airfoil shape capable of generating a decompression region behind the duct and suppressing generation of a vortex behind the duct. The tip is inside the duct, the rear end is provided protruding from the rear end of the duct so as to be close to the tip of the decompression area generated behind the duct, and the impeller blades are in the maximum wind speed area inside the duct. It is characterized by being provided.
[0006]
ADVANTAGE OF THE INVENTION According to this invention, when the wind which goes to the back from the front of a duct arises, a "pressure reduction area" can be generated, suppressing generation of a vortex behind a duct. Thus, it is possible to increase the wind speed inside the duct due to the drawing of the wind in the decompression region, while eliminating the situation where the flow of the wind from the front of the duct to the inside of the duct is obstructed by the vortex behind the duct.
[0007]
On the other hand, according to the knowledge obtained by the inventor of the present application, the tip of the decompression region is tapered and unstable, and tends to fluctuate in the radial direction of the duct. Disappears. In this case, it is not possible to increase the wind speed inside the duct, and thus to improve the power generation efficiency.
[0008]
However, since the rear end of the pencil body protrudes from the rear of the duct so as to approach the front end of the decompression region as in the present invention, the front end of the decompression region is attracted to the rear end of the pencil body and wobble. Is suppressed. Thereby, while the wind is blowing from the front of the duct to the rear, it is possible to suppress a situation in which the front end of the decompression region fluctuates and the decompression region disappears entirely. Then, the decompression region behind the duct is constantly maintained, and an increase in the wind speed inside the duct can be ensured.
[0009]
Further, since the blades of the impeller are provided in the maximum wind speed region inside the duct, the impeller can be rotated to the maximum.
[0010]
Therefore, according to the wind turbine generator of the present invention, (1) the wind speed inside the duct increases due to the generation of the decompression region behind the duct, (2) the steady maintenance of the decompression region by suppressing the fluctuation of the tip of the decompression region, (3) The power generation efficiency can be further improved through rotation of the impeller in the maximum wind speed region inside the duct.
[0011]
Further, in the wind turbine generator of the present invention, the chord in the airfoil of the side wall cross section of the duct is inclined at a predetermined angle with respect to the duct axis, and is adjusted to the position of the tip of the decompression region that changes according to the predetermined angle. The projecting length of the rear end of the pencil body from the rear of the duct is adjusted.
[0012]
The present invention is based on the following findings obtained by the present inventors.
[0013]
That is, the chord in the airfoil of the side wall cross section of the duct is inclined with respect to the duct axis, so that the degree of decompression in the decompression region behind the duct varies. Therefore, by adjusting the inclination so that the degree of decompression in the decompression region is maximized, the wind flowing into the duct from the front of the duct is more strongly drawn by the decompression region behind the duct, and the wind speed inside the duct is further increased. Can be faster.
[0014]
Further, as the inclination increases, the position of the leading end of the decompression region generated behind the duct shifts forward. Therefore, the protrusion length from the duct is adjusted so that the rear end of the pencil body reaches the front end of the decompression region in accordance with the inclination, whereby it is possible to suppress the fluctuation of the front end of the decompression region.
[0015]
Therefore, according to the wind power generator of the present invention, in addition to the above (1) to (3), (4) the power generation efficiency can be improved by maximizing the degree of decompression in the decompression region behind the duct and maximizing the wind inside the duct. Maximization can be achieved.
[0016]
Further, in the wind turbine generator according to the present invention, the predetermined angle is set in a range of 2 ° to 12 °, and a protruding length of the pencil body from the rear of the duct is set in a range of 0.1 to 0.4 times the duct length. It is characterized by having been done.
[0017]
Here, the “predetermined angle” is defined as a “positive” angle of inclination such that the leading edge of the wing of the chord is further away from the duct axis than the trailing edge of the wing.
[0018]
In the wind turbine generator of the present invention, the impeller blades are provided within a range of 0.07 times the duct length in the front and 0.18 times the duct length in the rear based on the minimum inner diameter portion of the duct. It is characterized by having been done.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a wind turbine generator according to the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of the wind turbine generator of the present embodiment, and FIGS. 2 to 4 are functional explanatory diagrams of the wind turbine generator of the present embodiment.
[0020]
The wind turbine generator shown in FIG. 1 has a substantially cylindrical duct 1, an impeller 2 having a plurality of outwardly projecting blades 22 and rotatable around a duct axis x, and a streamlined pencil body 3 together with the impeller 2. And a nacelle 5 for accommodating the generator 4 that utilizes the rotational force of the impeller 2 transmitted via the rotating shaft 24. The nacelle 5 is fixed to the duct 1 by a column 6 projecting from the inner wall of the duct 1. Energy generated by the generator 4 is supplied to the outside via a lead 42 penetrating the column 6 and the duct 1.
[0021]
The cross-sectional shape of the side wall of the duct 1 is an airfoil. This is because a decompression region can be generated behind the duct 1 and the generation of a vortex behind the duct 1 can be suppressed as described later. The side wall cross-sectional shape of the duct 110 is a known airfoil _{NACA65 3 -618 (9-0.5), NACA63} 3 -618, etc. FA66-S-196V1 is employed.
[0022]
The chord 11 of the airfoil having a side wall cross section of the duct 1 is inclined by a predetermined angle θ with respect to the duct axis 12. The predetermined angle θ is defined as positive in the direction in which the ratio of the front end diameter to the rear end diameter of the duct 1 increases.
[0023]
The pencil body 3 is provided such that the tip end of the impeller 2 corresponding to the tip end thereof is inside the duct 1, and the rear end of the nacelle 4 corresponding to the rear end protrudes from the rear end of the duct 1. Projection length L ₂ from the duct 1 of the rear end of the pencil body 3 is set to c (> 0) times of the duct length L _1. The coefficient c is expressed as a monotonically decreasing function c (θ) that satisfies the conditions of c (2 °) = 0.4 and c (12 °) = 0.1 using the predetermined angle θ as a variable. This is to bring the rear end of the pencil body 3 close to the front end of the decompression region generated behind the duct 1 as described later.
[0024]
Maximum wind region 13 the blade 21 is inside the duct 1 of the impeller 2, i.e., 0 with respect to the minimum inner diameter portion 14 of the duct 1, 0.07 times the duct length L ₁ in front and at the rear of the duct length. It is provided in a range of 18 times.
[0025]
The function of the wind power generator having the above configuration will be described with reference to FIGS.
[0026]
The inventor of the present application examined the flow and velocity of the wind near the duct 1 by simulation when a wind was generated from the front to the rear of the duct 1.
[0027]
This simulation is described in This was performed according to the method described in Kuwahara's dissertation, "Unsteady Flow Simulation and Its Visualization" (American Aviation and Space Society AIAA 99-3405). According to this method, first, a virtual lattice system is formed in space, and a Navier-Stokes equation (an equation representing the law of conservation of momentum of a continuum) is established at each lattice point. Then, the partial differential equation of the Navier-Stokes equation at one grid point is factored in with the influence of the fluid at other nearby grid points, and a partial differential equation for simulation is established. Then, by solving this partial differential equation, the wind speed at each grid point is obtained.
[0028]
Also, when this simulation, 8.7 ° a predetermined angle theta, the duct length _{L 1} 5,000 [mm], the rear end projection length _{L 2} of the pencil body 3 1,000 [mm] (= 0.20L 1 ), The minimum inner diameter of the duct 1 was 1,800 [mm], and the tip diameter was 3,166 [mm].
[0029]
The following was found from the simulation results. That is, according to this wind power generator, when a wind from the front to the rear of the duct 1 is generated, the decompression region 50 can be generated as shown by the oblique lines in FIG. Looking at the flow of the wind represented by the solid line in FIG. 3, the generation of the vortex behind the duct 1 is suppressed. Therefore, it is possible to increase the wind speed inside the duct 1 due to the drawing of the wind in the decompression region 50 while eliminating the situation where the flow of the wind from the front of the duct 1 into the duct 1 is obstructed by the vortex behind the duct 1.
[0030]
FIG. 2 shows the constant wind speed line in the duct 1 together with the acceleration when the wind speed in front of the duct 1 is 1.0. From FIG. 2, it can be seen that the speed increase in the maximum wind speed region 13 of the duct 1 is 2.6, that is, the wind speed in the region 13 is 2.6 times the wind speed at the tip end. Wind energy, wind velocity v, about 3.1 of the cross-sectional area of the fluid density [rho, is represented as ρSv ^3/2 as the cross-sectional area S of the duct 1, the opening cross-sectional area of the duct 1 in the present embodiment, the minimum inner diameter position As a result, the wind energy in the maximum wind speed region 13 of the duct 1 can be amplified to 2.6 ³ /3.1 to 5.67 times the wind energy in front of the duct 1.
[0031]
Further, as shown in FIG. 2, the rear end of the pencil body 3 protrudes from the rear of the duct 1 and reaches the front end 51 of the decompression region 50. Thereby, the front end portion 51 of the decompression region 50 is attracted to the rear end portion of the pencil body 3 and is stabilized, and its fluctuation is suppressed. Thereby, while the wind is blowing from the front to the rear of the duct 1, it is possible to suppress a situation in which the distal end portion 51 of the decompression region 50 fluctuates and the decompression region 50 disappears as a whole. Then, the decompression region 50 behind the duct 1 is constantly maintained, and an increase in the wind speed inside the duct 1 can be secured.
[0032]
Further, since the blades 21 of the impeller 2 are provided in the maximum wind speed region 13 inside the duct 1, the impeller 2 can be rotated to the maximum.
[0033]
Therefore, according to the wind turbine generator of the present invention, (1) the increase of the wind speed inside the duct 1 due to the generation of the decompression region 50 behind the duct 1, and (2) the decompression region 50 due to the suppression of the fluctuation of the front end 51 of the decompression region 50. And (3) rotation of the impeller 2 in the maximum wind speed region 13 inside the duct 1 to further improve the power generation efficiency.
[0034]
In addition, in FIG. 4, when the predetermined angle θ is changed and the rear end protrusion length L ₂ (= c (θ) · L ₁ ) of the pencil body 3 is changed accordingly, the maximum wind speed region 13 of the duct 1 is changed. The simulation result of the acceleration is shown. From FIG. 4, when the predetermined angle θ is set to 2 ° or more and 12 ° or less, the speed increase of the wind in the duct 1 can be maximized (= 2.6). That is, when the predetermined angle θ is set to 2 ° or more and 12 ° or less, the degree of decompression of the decompression region 50 behind the duct 1 becomes maximum, and the wind flowing into the inside of the duct 1 from the front of the duct 1 is reduced. Due to the fact that it is drawn in more strongly by 50, the wind speed inside the duct 1 can be further increased.
[0035]
Accordingly, setting the predetermined angle θ to 12 ° or less 2 ° or more, by adjusting the rear end projection length L ₂ of the pencil body 3 in accordance with this, the ▲ 1 ▼ ~ ▲ 3 ▼ was added, ▲ 4 ▼ Power generation efficiency can be maximized by maximizing the degree of decompression in the decompression region behind the duct and maximizing the wind inside the duct.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a wind power generator according to an embodiment of the present invention. FIG. 2 is a functional explanatory diagram of the wind power generator of the present embodiment. FIG. 3 is a functional explanatory diagram of a wind power generator of the present embodiment. Functional explanatory diagram of the wind turbine generator of the embodiment
1 ‥ duct, 11 ‥ chord, 12 ‥ duct shaft, 13 ‥ maximum wind speed region, 14 ‥ minimum inside diameter, 2 ‥ impeller, 21 ‥ blade, 22 ‥ rotary shaft, 3 ‥ pencil body, 4 ‥ generator, 5 ‥ nacelle

Claims (4)

A substantially cylindrical duct;
An impeller having a plurality of blades protruding outward and rotatable around a duct axis;
A wind power generator comprising a streamlined pencil body together with the impeller, and a nacelle accommodating a generator utilizing the rotational force of the impeller,
The side wall cross section of the duct has an airfoil shape that can generate a decompression region behind the duct and suppress the occurrence of eddy current behind the duct,
A pencil body is provided with its tip part inside the duct, and its rear end protrudes from the rear end of the duct so as to be close to the front end of the decompression area generated behind the duct. A wind power generator provided in a wind speed region. The chord of the airfoil of the side wall cross section of the duct is inclined by a predetermined angle with respect to the duct axis, and the rear end of the pencil body is adjusted from the rear of the duct at the rear end of the pencil body in accordance with the position of the front end of the decompression region that changes according to the predetermined angle. The wind power generator according to claim 1, wherein the protrusion length of the wind power generator is adjusted. The said predetermined angle is made into the range of 2 degrees-12 degrees, The protruding length of the pencil body from the duct back is set in the range of 0.1-0.4 times the duct length. Item 3. A wind power generator according to Item 2. The impeller blades are provided within a range of 0.07 times the duct length in the front and 0.18 times the duct length in the rear based on the minimum inner diameter portion to the duct. Item 4. The wind power generator according to item 1, 2 or 3.

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