CN102011710A - Wind machine blade - Google Patents

Abstract

The invention relates to a wind turbine blade, which belongs to the field of wind power generation. It is composed of the front part of the blade and the rear part of the blade, the front part of the blade is the blade tip part to the blade maximum chord length section (12), and the blade rear part is the blade maximum chord length section (12) to the blade root part; it is characterized in that : The above-mentioned blade rear portion is composed of a structural component (9) for installing the blade root and bearing the load of the blade and an aerodynamic component (10) for capturing wind energy from the inside to the outside; the above-mentioned structural component (9) and the aerodynamic component (10) The shape of the aerodynamic part (10) transitions from the maximum chord length (12) of the blade to the aerodynamic airfoil (2) of the blade root, and the specific transition form is through the airfoil of each section at the front of the blade and the aerodynamic The airfoil (2) is obtained by lofting. The invention can make full use of the wind energy inside the wind wheel, improve the utilization efficiency of the wind energy, and increase the power generation capacity of the wind turbine and the blades of the wind turbine.

Description

a wind turbine blade

technical field

The invention relates to a wind turbine blade, which belongs to the field of wind power generation. the

Background technique

Renewable energy is the best way to solve the energy crisis, and wind power is the industry with the fastest development, the most mature technology and the broadest prospect in the renewable energy industry. my country has a vast territory and is rich in wind energy resources. With the continuous advancement of science and technology, the economics of wind power generation has been continuously improved. In addition, my country has taken renewable energy as an important part of my country's energy strategy, and wind power has a huge potential market.

The aerodynamic efficiency of wind turbine blades determines the quality of a wind turbine in the market, so the design of the aerodynamic shape of wind turbine blades is the key to wind turbine design. The root of the large-scale wind turbine blades that are mainstream in the market is basically a cylinder, and the blade root to about 1/5 of the radial direction is approximately a cylinder, so that the wind energy inside the wind wheel is not used, and the cylinder has a great impact on the entire wake. The flow field also plays a role. At present, the industry has not paid much attention to this problem. It is believed that the linear velocity of the blade root is relatively small, and the moment arm is relatively small, so no force will not have much impact. Therefore, many people's optimization of the blade is limited to the middle and tip of the blade, without considering the root of the blade. Using the classic theory of wind turbine blade aerodynamic shape optimization, that is, the Glauert theory optimization result has a relatively large chord length at the blade root, but considering the structure and connection with the hub, the actual blade root adopts a cylindrical structure, and the chord length is much smaller than the optimization result.

There are many patents that improve the aerodynamic performance of blades by means of flow control, such as adding flaps, rotating cylinders on the leading edge, jet flow control, etc. For the existing wind turbine blades, the aerodynamic shape of the blade root can be optimized and modified, and it can greatly improve the aerodynamic performance of the wind turbine. However, there is no special design for the blade root in China. Related technical reports on improving blade aerodynamic performance.

Contents of the invention

The object of the present invention is to provide a wind turbine blade that can make full use of the wind energy inside the wind rotor, improve the efficiency of wind energy utilization, and increase the power generation capacity of the wind turbine.

A wind turbine blade is composed of a front part of a blade and a rear part of a blade, the front part of the blade is the section from the blade tip to the maximum chord length of the blade, and the rear part of the blade is the section from the maximum chord length of the blade to the root of the blade; it is characterized in that: The rear part of the above-mentioned blade is composed of structural components for installing the blade roots and bearing the load of the blade and aerodynamic components for capturing wind energy from the inside to the outside; there is a cavity between the above-mentioned structural components and the aerodynamic components; the shape of the above-mentioned aerodynamic components is determined by the blade The transition from the maximum chord length to the aerodynamic airfoil of the blade root is carried out. The specific transition form is obtained by setting out the airfoil of each section at the front of the blade and the aerodynamic airfoil of the blade root.

The shape of the front part of the above-mentioned blade is obtained according to the classic theory of wind turbine blade aerodynamic shape optimization, that is, the Glauert theory, which can maximize the capture of wind energy. The design criterion of the structural components at the rear of the blade is mainly based on the blade structure design, and the design criterion of the aerodynamic components is mainly based on the aerodynamic design of the blade. Such a design can not only exert the wind energy capture ability of the blade root, but also take into account the strong bearing capacity of the blade root.

A wind turbine blade, characterized in that: the chord length of the blade root aerodynamic airfoil of the aerodynamic component is greater than the structural chord length of the blade root of the structural component, and is smaller than the maximum chord length of the blade; the shape of the blade root aerodynamic airfoil is determined by the following method: The shape of the aerodynamic airfoil is composed of 5 tangent arcs that are tangent to the shape of the structural airfoil. arc, the upper arc of the trailing edge; the upper arc of the leading edge is inscribed with the structural outer circle, the lower arc of the leading edge is inscribed with the structural outer circle, the arc of the leading edge is inscribed with the upper arc of the leading edge and the lower circle of the leading edge The arcs are all inscribed, the center of the arc on the rear edge is on a straight line that passes through the center of the structural type and is 60° from the neutral line, and is inscribed with the outer circle of the structural type, and the center of the arc on the rear edge is on a line that passes through the center of the structural type and is in line with the outer circle of the structural type. On a straight line formed by the neutral line at -45°, it is circumscribed to the outer circle of the structural type; the above-mentioned neutral line refers to the structural circle, and is perpendicular to the line connecting the center of the upper arc of the leading edge and the lower arc of the leading edge; the above-mentioned The junction of the lower arc of the trailing edge and the upper arc of the trailing edge forms the thickness of the trailing edge, and the thickness of the trailing edge is 0.5% to 1% of the structural diameter; the relative thickness of the above-mentioned blade root aerodynamic airfoil is less than 100%.

The shape of the blade root aerodynamic airfoil is similar to that of a general thick airfoil, and the asymmetry of the upper and lower surface shapes produces camber, which improves aerodynamic performance. The tangential connection of the five arc surfaces ensures the continuity of the radius of curvature of the surface shape, and the position of the center of the upper and lower arcs of the trailing edge can be changed. The above positions are used as reference values to ensure that the airfoil has curvature. The relative thickness depends on the actual wind field conditions. The relative thickness of the root aerodynamic airfoil of the wind field with high annual average wind speed is large, and vice versa. The thickness of the trailing edge is determined by the actual production process. When the upper and lower trailing edges of the blade are bonded, the thickness will inevitably be produced, and the airfoil with a thick trailing edge will have better performance than the airfoil with a sharp trailing edge. Generally, the root of the blade is circular, and most of the rear part of the blade is cylindrical. When the wind rotor rotates, the rear part of the blade can neither capture wind energy, but also produce a vortex street in the wake area of the blade, destroying the flow field. The aerodynamic components using the blade root aerodynamic airfoil can not only capture wind energy, provide wind energy utilization coefficient, but also improve the flow field.

The above-mentioned structural components and the front part of the blade can be integrated; then the aerodynamic component is fixedly connected with the structural component and the front part of the blade at the maximum chord length of the blade. Such a structure is simple and easy to implement. The integrity of the structural components and the front part of the blade ensures the continuous force transmission of the blade and meets the structural design criteria. The aerodynamic components are pasted on the structural components and the intersection of the front and rear of the blade (that is, the maximum chord length) after the shape is determined and manufactured separately.

The blade root structural airfoil of the above structural component may be a circle whose radius is consistent with the radius of the blade root flange. This combination facilitates installation.

The application scope of the present invention is relatively wide. The design of the front and rear of the blade can be considered comprehensively when designing the blade, or the aerodynamic components at the rear of the blade can be designed separately on the basis of the existing cylindrical root blade, and then the aerodynamic components can be pasted on the existing blade. That is, the present invention can modify the existing blades to improve the aerodynamic performance of the blades.

Description of drawings

Fig. 1 is the schematic diagram of blade root airfoil of the embodiment of the present invention;

Fig. 2 is the front view of the embodiment of the present invention;

Fig. 3 is a front view of an embodiment of the present invention;

Fig. 4 is to utilize the wind energy utilization coefficient comparison of embodiment blade of the present invention and general blade;

Fig. 5 is a comparison of thrust coefficients between the blades of the embodiments of the present invention and the general blades.

Detailed ways

Figures 1 to 5 show the shape and performance of blades in one embodiment of the present invention. The length of the blade is 41 meters, the rated power is 1500kW, the maximum chord length of the blade is 7.5 meters from the blade root, and the diameter of the blade root flange is 1.89 meters.

Referring to FIG. 1 , it is the blade root airfoil of this embodiment, and the blade root airfoil is composed of structural type 1 and aerodynamic type 2 . Structural type 1 is a circle with radius R, R is determined by the radius of the blade root connecting flange, and structural type 1 and the flange are connected by bolts. The aerodynamic type 2 is composed of part of the shape of the structural type 1, 5 tangent arcs and the thickness surface 8 of the trailing edge. The 5 tangent arcs are the upper surface 3 of the leading edge, 4 The upper surface 6 of the edge and the lower surface 7 of the trailing edge. The center of the arc on the upper surface 3 of the front edge is 2/5R directly below the center of the structure type 1, the radius of the arc is 7/5R, and it is inscribed with the outer circle of the structure type 1. The arc center of the lower surface 5 of the front edge is at 1/2R directly above the center of the structural type 1, and the radius of the arc is 3/2R, which is inscribed with the outer circle of the structural type 1. The 4 arcs of the leading edge are inscribed with the 3 arcs of the upper surface of the leading edge and the 5 arcs of the lower surface of the leading edge, and the radius is 1/2R. The center of the arc 6 on the upper surface of the rear edge is on a straight line passing through the center of the structural type 1 and forming a 60° angle to the neutral line, with a radius of 4R, inscribed with the outer circle of the structural type 1. The center of the arc on the lower surface of the trailing edge is on a straight line passing through the center of structure type 1 and forming -45° with the neutral line, with a radius of 2R and circumscribed to the outer circle of structure type 1. The thickness surface 8 of the trailing edge is vertical, and the thickness is 0.5% to 1% of the diameter of the structural type 1. In this embodiment, the aerodynamic chord length of the blade root airfoil is 2.83 meters, and the relative thickness is 66.7%.

Referring to Fig. 2, it is a front view of the blade of this embodiment. The part between the root of the blade and the maximum chord section of the blade is divided into a structural component 9 and an aerodynamic component 10 . Structural component 9 is a cylindrical section in the first 0.5 meters (blade root to section 11), which is used to embed bolts, and the cross-sectional shape of section 11 is round and section 12 (the blade's maximum chord length). Stake out to get. The aerodynamic component 10 is obtained by setting out the aerodynamic type of the blade root and the airfoil of each section after the section 12 . The structural part of the blade root is the main bearing part of the blade, and the structural part of the blade root is integrated with the center of the blade and the tip of the blade and is manufactured as a whole. The aerodynamic part of the blade root is manufactured separately according to the already designed shape, and then it is pasted on the structural component and the section 12.

Referring to Fig. 3, it is the front view of the blade of this embodiment (viewed from the blade root to the blade tip), the maximum chord length (12) is 7.5 meters away from the blade root. A cavity is formed between the pneumatic type and the structural type.

Referring to Fig. 4, it is a comparison of the wind energy utilization coefficient between the blades of the embodiments designed by the present invention and the general blades designed without the present invention. It can be seen that the wind energy utilization coefficient of the blade designed by the present invention is greatly improved. Especially when the blade tip speed ratio is larger (lower wind speed), the wind energy utilization coefficient increases significantly, which corresponds to the high wind frequency throughout the year, so the annual power generation can also increase significantly.

Referring to FIG. 5 , it is a comparison of the thrust coefficient between the blades of the embodiments designed by the present invention and the general blades not designed by the present invention. The blades are the same as the above blades. The thrust coefficient does not increase after the wind utilization coefficient is increased, but the thrust coefficient decreases slightly when the tip speed ratio is larger (lower wind speed).

Claims (4)

1. a pneumatic equipment blades made is made of blade front portion and blade rear portion, and the blade front portion is tip segment to blade maximum chord length cross section (12), and the blade rear portion is blade maximum chord length cross section (12) to leaf root part;

It is characterized in that: above-mentioned blade rear portion comprises successively outward that by interior being used for the Pneumatic component (10) that blade root installs and bear the structure member (9) of blade loading and be used for capturing wind energy forms; Between said structure parts (9) and the Pneumatic component (10) is cavity; The profile of above-mentioned Pneumatic component (10) begins to transit to the pneumatic aerofoil profile of blade root (2) by blade largest chord strong point (12) to be located, and concrete interim form obtains by anterior each cross section aerofoil profile of blade and the pneumatic aerofoil profile of blade root (2) setting-out.

2. a kind of pneumatic equipment blades made according to claim 1 is characterized in that:

The pneumatic aerofoil profile of blade root (2) chord length of above-mentioned Pneumatic component (10) is greater than the leaf and root structure chord length of structure member, simultaneously less than the blade maximum chord length;

The profile of the pneumatic aerofoil profile of above-mentioned blade root (2) is determined by following mode:

Pneumatic aerofoil profile profile is by forming with tangent 5 tangent arcs of structure aerofoil profile profile, and these 5 circular arcs are defined as under circular arc on the leading edge (3), leading edge circular arc (4), the leading edge under circular arc (5), the trailing edge circular arc (6) on circular arc (7), the trailing edge successively;

Wherein circular arc (3) and structural type (1) cylindrical inscribe on the leading edge, circular arc under the leading edge (5) and structural type (1) cylindrical inscribe, circular arc (5) inscribe all under circular arc (3) and the leading edge on leading edge circular arc (4) and the leading edge, the center of circle of circular arc on the trailing edge (6) is on crossing structural type (1) center of circle and becoming 60 ° straight line with the neutral line, with structural type (1) cylindrical inscribe, the center of circle of circular arc under the trailing edge (7) circular arc is on crossing structural type (1) center of circle and becoming-45 ° straight line with the neutral line, and is circumscribed with structural type (1) cylindrical; The above-mentioned neutral line referred to the structural type circle, and perpendicular to the circle center line connecting of circular arc (5) under circular arc on the leading edge (3) and the leading edge;

Circular arc (6) joining place forms trailing edge thickness (8) on circular arc under the above-mentioned trailing edge (7) and the trailing edge, and trailing edge thickness (8) is 0.5%～1% of structural type (1) diameter;

The relative thickness of the pneumatic aerofoil profile of above-mentioned blade root (2) is less than 100%.

3. according to claim 1 or 2 described a kind of pneumatic equipment blades mades, it is characterized in that:

Said structure parts (9) and blade front portion are an integral body; Above-mentioned Pneumatic component (10) is fixedlyed connected with structure member (9) and blade front portion in blade largest chord strong point (12).

4. a kind of pneumatic equipment blades made according to claim 1 and 2 is characterized in that:

The leaf and root structure aerofoil profile (1) of said structure parts (9) is radius and the consistent circle of blade root flange radius.

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