CN101749193B

CN101749193B - High-efficient wind powered generator with start-up wind speed being set and blades thereof

Info

Publication number: CN101749193B
Application number: CN200910188890A
Authority: CN
Inventors: 韩建景; 李永泉; 欧业墅; 韩洁; 林韧锋; 卢俊华
Original assignee: Individual
Current assignee: Shenzhen City Feisheng New Energy Co Ltd
Priority date: 2009-12-09
Filing date: 2009-12-09
Publication date: 2012-09-26
Anticipated expiration: 2029-12-09
Also published as: CN101749193A

Abstract

The invention discloses a high-efficient wind powered generator with start-up wind speed being set and a blade thereof. The wind powered generator comprises the blade, wherein the blade comprises a root part and a blade tip; the root part is arranged at one end of the blade for installation, and the blade tip is arranged at the other end of the blade; the installation angle of the blade near the root part is greater; and the chord length of the blade is increased near the area of the root part non-linearly. The wind powered generator can be started up with low wind speed on the premise that the generated power is not lost basically, thereby greatly improving the power generation efficiency.

Description

High-efficiency wind driven generator capable of setting starting wind speed and blade thereof

Technical Field

The invention relates to a generator, in particular to a high-efficiency wind driven generator capable of setting starting wind speed and a blade thereof.

Background

The design theory of the blade of the wind driven generator is various, such as Betz theory, vortex theory, phyllotactic theory, momentum theory and the like, and the theories provide great help for the design of the blade of the wind driven generator and the design of the whole machine.

The simplified windmill model derived from the Betz theory is based on the theoretical optimal operation condition, and does not consider the distribution and the influence of the blade vortex, so that the simplified windmill model has a larger difference from the actual application; in the later period, Schmits and Glauert fully consider peripheral vortexes such as a central vortex, a boundary vortex and a vortex of a blade tip of a wind wheel and vortexes behind the wind wheel, a Schmits and Glauert design model based on a vortex and chlorophyll theory is generated, and the design theory of blades is further improved; wilson further researches the influence of tip loss and lift-drag ratio of the blade on the optimal performance of the blade and the performance of the wind wheel under the non-design working condition on the basis of a Glauert design model, and provides a Wilson design model. Besides, many other aerodynamics experts have studied more relevant theories, and the design methods most used in the wind turbine blade design in the industry at present are schmitts and Glauert models.

The above various blade design models are based on how the blade exerts the best efficiency at the rated wind speed, and the analysis and inference made by the blade in the standard rotation process state are set without considering the factors such as the starting wind speed, so that the starting wind speed of the blade designed according to the model in the market at present is higher and is difficult to grasp. In practical application, the designed external conditions of the blade are greatly different between a static state and a moving state, so that the designed blade has the problems of high starting wind speed, low efficiency and the like.

Chinese patent application No. 200810120290.8, published on 21.1.2009, discloses a fan structure of a wind power generator, wherein the fan comprises a hub, a pressure plate and blades. Set up first through-hole on the clamp plate, be provided with the second through-hole on the blade, be provided with the screw hole on the wheel hub, first screw passes first through-hole and second through-hole respectively and screw hole cooperation, first through-hole and second through-hole are provided with screw adjustment clearance, wheel hub's inboard is provided with blade jacking system, be used for with blade jack-up, the existence in screw adjustment clearance, the purpose makes first screw still can pass the clamp plate respectively and the blade is fixed on wheel hub, in order to reach the purpose that adjusting blade installation angle improves wind energy utilization.

Although the above-mentioned patent application technology can adjust the installation angle of the blade according to different environments, once the wind turbine generator is installed, the installation angle of the blade cannot be adjusted during use, and the requirement of low starting wind speed and high power generation efficiency cannot be met.

Disclosure of Invention

The invention mainly solves the technical problem of providing a high-efficiency wind driven generator capable of setting a starting wind speed and a blade thereof, which can realize low wind speed starting on the premise of basically not losing generating power and greatly improve generating efficiency.

In order to solve the technical problems, the invention adopts a technical scheme that: there is provided a blade for a wind turbine, the blade comprising a root portion at one end for mounting and a tip portion at the other end, the mounting angle of the blade adjacent the root portion being relatively large and the chord length of the blade increasing in non-linear acceleration in the region adjacent the root portion.

Wherein the chord length C_rsAnd the mounting angle theta_rsThe airfoil chord length and the installation angle of the blade at the radius r are as follows:

C_rs＝C_r×k_crs

θ_rs＝θ_r×k_θrs

wherein,

<math><mrow> <mi>Cr</mi> <mo>=</mo> <mfrac> <mrow> <mn>16</mn> <mi>π</mi> <mo>·</mo> <mi>r</mi> </mrow> <mrow> <msub> <mi>C</mi> <mi>L</mi> </msub> <mi>B</mi> </mrow> </mfrac> <msup> <mi>Sin</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mfrac> <mrow> <mi>arccty</mi> <mrow> <mo>(</mo> <mfrac> <mi>r</mi> <mi>R</mi> </mfrac> <msub> <mi>λ</mi> <mi>o</mi> </msub> <mo>)</mo> </mrow> </mrow> <mn>3</mn> </mfrac> <mo>)</mo> </mrow> <mo>,</mo> </mrow></math>

<math><mrow> <mi>θr</mi> <mo>=</mo> <mfrac> <mn>2</mn> <mn>3</mn> </mfrac> <mi>arccty</mi> <mrow> <mo>(</mo> <mfrac> <mi>r</mi> <mi>R</mi> </mfrac> <msub> <mi>λ</mi> <mi>o</mi> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mi>α</mi> <mo>,</mo> </mrow></math>

the Vs is a preset starting wind speed value, the range is 1.2-3.2 m/s, the R is a value of the distance between the blade and the center of the wind wheel and is a position R, the R is the design radius of the blade, and the a is an adjusting coefficient.

Wherein the chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade at radius r, C_rsAnd theta_rsRespectively as follows:

C_rs＝C_r×k_crs

θ_rs＝θ_r×k_θrs

wherein,

θr＝arc cotk₄-α，

<math><mrow> <msub> <mi>k</mi> <mn>1</mn> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mn>3</mn> </mfrac> <mi>arctan</mi> <mrow> <mo>(</mo> <mfrac> <mi>r</mi> <mi>R</mi> </mfrac> <msub> <mi>λ</mi> <mi>o</mi> </msub> <mo>)</mo> </mrow> <mo>+</mo> <mfrac> <mi>π</mi> <mn>3</mn> </mfrac> <mo>,</mo> </mrow></math>

Wherein the adjustment coefficient a is 2, 3, 4, 5 or 6, and the value of a is inversely proportional to the manufacturing level of the generator and the blade.

Wherein the blade length is increased by 1-15% compared with the standard theoretical calculation method and is inversely proportional to the starting wind speed.

Wherein, the blade tip of the blade is provided with a winglet smoothly connected with the blade tip.

The winglet is of a symmetrical wing type structure, the length of the winglet is 5% -10% of the designed length of the blade, the winglet inclines backwards from the windward side, the inclination angle is 15-60 degrees, the winglet inclines backwards along the rotation plane of the impeller along the downwind direction, the inclination angle is 8-30 degrees, and the connecting radius of the winglet and the blade tip is 1/4 of the length of the winglet.

In order to solve the technical problem, the invention adopts another technical scheme that: there is provided a wind power generator comprising a blade having a root at one end for mounting and a tip at the other end, the blade having a relatively large mounting angle adjacent the root and the chord length of the blade increasing in non-linear acceleration adjacent the root region.

C_rs＝C_r×k_crs

wherein,

C_rs＝C_r×k_crs

wherein,

θr＝arccotk₄-α，

The invention has the beneficial effects that: compared with the condition that the prior art can not meet the requirements of low starting wind speed and high power generation efficiency, the invention introduces parameters such as starting wind speed and the like on the basis of a standard theory, particularly more applied Schmits and Glauert models through long-term theoretical analysis and multiple experiments, corrects the original calculation model, solves the theory and practice of blade design of the fixed-pitch wind driven generator related to the starting wind speed, can design blades related to the starting wind speed according to the requirement of the starting wind speed in a larger range, basically does not lose or hardly loses the power generation power compared with the prior art, greatly meets the requirements in the industry, and plays a larger role in the development of the wind driven generator technology. Experiments prove that the starting wind speed value can be as low as 1.2-3.2 m/s, namely, the wind power generator can be started and generate power smoothly under the wind power condition that the wind power generator in the prior art cannot be started, and the power generation efficiency is greatly improved.

Drawings

FIG. 1 is a schematic front view of a first embodiment of a blade according to the present invention;

FIG. 2 is a schematic comparison of a prior art blade in root section and a blade of the present invention in root section;

FIG. 3 is a perspective view of a second embodiment of the blade of the present invention;

fig. 4 is another perspective view of a second embodiment of a vane of the present invention.

Detailed Description

In order to explain technical contents, structural features, and objects and effects of the present invention in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.

In order to solve the problems in the prior art, the inventor introduces parameters such as starting wind speed and the like on the basis of more applied Schmits and Glauert models through long-term theoretical analysis and multiple experiments, and corrects the original calculation model to obtain the blade embodiment of the wind driven generator shown in the figures 1 and 2.

Referring to fig. 1 and 2, the blade 10 includes a root 11 at one end for mounting and a tip 12 at the other end, and the mounting angle θ of the blade 10 adjacent to the root 11_rsGreater, i.e. in the figure, mounting angle theta of region 13_rsLarger than other regions and the chord length C of the blade 10_rsThe nonlinear acceleration increases in the region adjacent to the root 11, i.e. the chord length C of the region 13 in the figure_rsThe non-linear acceleration increases, forming a bump-like structure. FIG. 2 shows a conventional blade 10' with a chord length C_rs' and mounting Angle θ_rs' are significantly smaller adjacent the root 11 as compared to the present invention.

At the angle theta of the blade 10 adjacent the root 11_rsLarge and chord length C_rsThe non-linear acceleration increases in the area adjacent to the root 11, which increases the windward side, increases the torque generated on the blade 10 when the fluid passes through the blade 10, and does not substantially affect the entire generated power or causes less loss of generated power during power generation.

Compared with the condition that the prior art can not meet the requirements of low starting wind speed and high power generation efficiency, the invention introduces parameters such as starting wind speed and the like on the basis of a standard theory, particularly more applied Schmits and Glauert models through long-term theoretical analysis and multiple experiments, corrects an original calculation model, solves the theory and practice of blade design of the fixed-pitch wind driven generator related to the starting wind speed, can design blades related to the starting wind speed according to the requirement of the starting wind speed in a larger range, basically does not lose or hardly loses power generation power compared with the prior art, greatly meets the requirements in the industry, and plays a larger role in the development of the wind driven generator technology.

The nonlinear acceleration increase may be in the shape of a protrusion or a single-sided nonlinear acceleration increase.

In another embodiment, the chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade 10 at the radius r of the blade 10, C_rsAnd theta_rsRespectively as follows:

C_rs＝C_r×k_crs

wherein,

the Vs is a preset starting wind speed value, the range is 1.2-3.2 m/s, the R is a value of the distance between the blade 10 and the center of the wind wheel and is the R position, the R is the design radius of the blade 10, and the a is an adjusting coefficient.

Experiments prove that the starting wind speed value can be as low as 1.2-3.2 m/s, namely, the wind power generator can be started and generate power smoothly under the wind power condition that the wind power generator in the prior art cannot be started, and the power generation efficiency is greatly improved.

The design method, the modified theory and the calculation formula can be modified on the basis of Schmits and Glauert calculation models (see the following attached below). The Schmits and Glauert calculation model refers to the chord length C of the blade 10_rAnd the mounting angle theta_rAnd (4) parameters. The chord length C_rAnd the mounting angle theta_rIs the chord length and stagger angle of the airfoil of the blade 10 at the radius r of the blade 10. The correction theory and the calculation formula refer to correction coefficient k which is obtained by derivation, analysis and experiment and is supplemented on the basis of Schmits and Glauert calculation models_cs、

The chord length C of the resulting blade 10_rsAnd the mounting angle theta_rs. The chord length C_rsAnd the mounting angle theta_rsIs the chord length and stagger angle of the airfoil of the blade 10 at the radius r of the modified blade 10.

In one embodiment, the chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade 10 at the radius r of the blade 10, C_rsAnd theta_rsRespectively as follows:

C_rs＝C_r×k_crs

wherein,

θr＝arccotk₄-α，

Wherein, when k_crsWhen the chord length is greater than or equal to 1, the corrected chord length C_rsIs equal to the correction factor k_crsIs equal to the chord length C_rThe product of (a); when the correction coefficient k is_crsPositive and negative 10% of 1, corrected chord length C_rsMay be equal to the chord length C_r. Corrected and calculated chord length C of blade 10_rsAnd the mounting angle theta_rsThe correction is within the reasonable extension range of the calculation model, the values of the existing design correction theory and the calculation result of the calculation model are respectively extended within 10 percent, and the basic ideas and ideas of the existing design correction theory of the blade 10 and the calculation model are still used.

The adjustment coefficient a of the above embodiments is 2, 3, 4, 5 or 6, and the value of a is inversely proportional to the manufacturing level of the generator and the blade 10. I.e., the higher the level, the smaller the coefficient may be; otherwise, it should take a larger value.

In order to better improve the generating efficiency of the generator, the length of the blade 10 is increased by 1-15% compared with the standard theoretical calculation method, and is inversely proportional to the starting wind speed. I.e. the lower the start-up wind speed requirement, the larger the value of the increase. After the increase of the length, because of the correction coefficient k_crsAndthe possible influence of (2) and the possible loss of generated power can be fully compensated for, or even increased.

Referring to fig. 3 and 4, in other embodiments, the blade 10 is provided with a smoothly connected winglet 14 at the tip 12. The winglet 14 is of a symmetrical wing type structure, the length of the winglet is 5% -10% of the design length of the blade 10, the winglet 14 inclines backwards from the windward side, the inclination angle is 15-60 degrees, the winglet 14 inclines backwards along the rotation plane of the impeller along the downwind direction, the inclination angle is 8-30 degrees, and the connecting radius of the winglet 14 and the blade tip 12 is 1/4 of the winglet length. In some embodiments, at least two or more airfoils may be provided throughout the length of the blade 10. Referring also to fig. 1 to 4, the present invention also provides a wind power generator according to the above theory and design, comprising a blade 10, wherein the blade 10 comprises a root 11 for mounting at one end and a tip 12 at the other end, the mounting angle of the blade 10 adjacent to the root 11 is larger, and the chord length of the blade 10 increases in the area adjacent to the root 11.

Wherein the chord length C_rsAnd the mounting angle theta_rsAt radius r of the blade 10Airfoil chord length and stagger angle of the blade 10, C_rsAnd theta_rsRespectively as follows:

C_rs＝C_r×k_crs

wherein,

The chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade 10 at the radius r of the blade 10, C_rsAnd theta_rsAre respectively provided withComprises the following steps:

C_rs＝C_r×k_crs

wherein,

θr＝arccotk₄-α，

In one example, a 2 kilowatt wind turbine was targeted and a Schmittz calculation model was used as an example to illustrate, in accordance with the present invention:

the main parameters of the design are as follows:

rated power: 2000W

Rated wind speed: 12 m/s

Rated rotation speed: 480 rpm

Theoretically calculating the diameter of the wind wheel: 2.9 m

Starting wind speed: 2 m/s

Adjusting coefficient: 4

The wind wheel diameter is corrected to 3.2 meters taking into account the influence of the air guide sleeve and the starting wind speed.

Meanwhile, before the radius ratio is 0.75,

C_rs＝C_r×k_crs

after the radius ratio is 0.75, take theta_rs＝θ_r；

C_rs＝C_r

According to the above main parameters, the calculation and comparison results are as follows:

table one: comparison between blade installation angle and chord length of the prior art and the embodiment of the invention

Taking the section at radius ratio of 0.2 as an example, the blade 10 profile data and profile map for the airfoil design of NACA4415 are as follows:

table two: comparison of blade profile data in airfoil design of the prior art and an embodiment of the present invention

In the present invention, the correction coefficient k_crsAnd

the correction design of the wing profile has no relation with aerodynamic parameters including but not limited to wing profile change, lift coefficient or drag coefficient of the wing profile, tip speed ratio and the like, so that the wing profile has very good applicability and simplicity.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A blade for a wind power plant, characterised in that the blade comprises a root at one end for mounting and a tip at the other end, that the mounting angle of the blade adjacent the root is relatively large and that the chord length of the blade increases in a non-linear acceleration in the region adjacent the root, the chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade at radius r, C_rsAnd theta_rsRespectively as follows:

C_rs=C_r×k_crs

θ_rs=θ_r×k_θrs

wherein,

the Vs is a preset starting wind speed value, the range is 1.2-3.2 m/s, the R is a value of the distance between the blade and the center of the wind wheel and is a position R, the R is the design radius of the blade, and the alpha is an adjusting coefficient.

2. A blade for a wind power plant, characterised in that the blade comprises a root at one end for mounting and a tip at the other end, that the mounting angle of the blade adjacent the root is relatively large and that the chord length of the blade increases in a non-linear acceleration in the region adjacent the root, the chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade at radius r, C_rsAnd theta_rsRespectively as follows:

C_rs=C_r×k_crs

θ_rs=θ_r×k_θrs

wherein,θr=arccotk₄-α，

3. Blade of a wind power generator according to claim 1 or 2, characterized in that: the adjustment coefficient a is 2, 3, 4, 5 or 6, the value of a being inversely proportional to the manufacturing level of the generator and the blade.

4. Blade of a wind power generator according to claim 1 or 2, characterized in that: the length of the blade is increased by 1% -15% compared with that of a standard theoretical calculation method, and is inversely proportional to the starting wind speed.

5. Blade of a wind power generator according to claim 1 or 2, characterized in that: and winglets which are connected smoothly are arranged at the blade tips of the blades.

6. The blade for a wind power generator according to claim 5, wherein: the winglet is of a symmetrical wing type structure, the length of the winglet is 5% -10% of the designed length of the blade, the winglet inclines backwards from the windward side, the inclination angle is 15-60 degrees, the winglet inclines backwards along the rotation plane of the impeller along the wind direction, the inclination angle is 8-30 degrees, and the connecting radius of the winglet and the blade tip is 1/4 of the length of the winglet.

7. A kind ofWind turbine comprising a blade, characterised in that the blade comprises a root at one end for mounting and a tip at the other end, that the mounting angle of the blade adjacent the root is relatively large and that the chord length of the blade increases in a non-linear acceleration adjacent the root, said chord length C_rsAnd the mounting angle theta_rsThe airfoil chord length and the installation angle of the blade at the radius r are as follows:

C_rs=C_r×k_crs

θ_rs=θ_r×k_θrs

wherein,

8. A wind turbine comprising a blade, wherein the blade comprises a root at one end for mounting and a tip at the other end, wherein the mounting angle of the blade adjacent the root is relatively large and wherein the chord length of the blade increases in non-linear acceleration in the region adjacent the root, and wherein the chord length C is greater than the chord length C_rsAnd the mounting angle theta_rsIs the airfoil chord length and stagger angle of the blade at radius r, C_rsAnd theta_rsRespectively as follows:

C_rs=C_r×k_crs

θ_rs=θ_r×k_θrs

wherein,

θr=arccotk₄-α，