CN102011710B - Wind machine blade - Google Patents

Abstract

The invention relates to a wind machine blade, belonging to the field of wind power generation. The wind machine blade comprises a blade front part and a blade back part; the blade front part is the part from the blade tip part to the blade section (12) with the biggest chord length; the blade back part is the part form the blade section (12) with the biggest chord length to the blade root part; the wind machine blade is characterized in that the blade back part comprises a structure component (9) for mounting blade root and bearing loads of the blade and a pneumatic component (10) for capturing wind energy in turn from inner to outer; a cavity is formed between the structure component (9) and the pneumatic component (10); the shape of the pneumatic component (10) is transitioned from the blade section with the biggest chord length to a pneumatic wing section (2) at the blade root; the specific transition form is obtained by lofting each section wing section at front part of the blade and the pneumatic wing section (2) at the blade root. The wind machine blade of the present invention can use the wind energy in a wind wheel fully, improve the use ratio of the wind energy, and increase the generating capacity of the wind machine.

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, Glauert theory, the 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 blade root aerodynamic airfoil is composed of five tangent arcs that are tangent to the structural shape. Circular arc, upper arc of the trailing edge; among them, 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 arc 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 inscribed with the outer circle of the structural type. On a straight line at -45° to the neutral line, it is circumscribed to the outer circle of the structural type; the above-mentioned neutral line refers to the center of the structural type, 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 5 arc-shaped 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 round, 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 a schematic diagram of a blade root airfoil according to an embodiment of the present invention.

Fig. 2 is a front view of an embodiment of the present invention.

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

Fig. 4 is a comparison of the utilization coefficient of wind energy between the blade of the embodiment of the present invention and the 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 an 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 Figure 1, it is the blade root airfoil of this embodiment, and the blade root airfoil is composed of structural type 1 and blade root aerodynamic airfoil 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 blade root aerodynamic airfoil 2 is composed of the partial shape of the structural type 1, 5 tangent arcs and the thickness 8 of the trailing edge. The 5 tangent arcs are respectively the leading edge upper arc 3, the leading edge The lower arc 5, the upper arc 6 of the trailing edge and the lower arc 7 of the trailing edge. The arc center of the arc 3 on the front edge is 2/5R directly below the center of the structural type 1, and the radius of the arc is 7/5R, which is inscribed with the outer circle of the structural type 1. The arc center of the lower arc 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 leading edge arc 4 is inscribed with the leading edge upper arc 3 and the leading edge lower arc 5, and the radius is 1/2R. The center of the arc 6 on the trailing 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 lower arc 7 of the trailing edge is on a straight line passing through the center of the structural type 1 and forming -45° with the neutral line, with a radius of 2R and circumscribed to the outer circle of the structural type 1. The thickness of the trailing edge is 8 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 Figure 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 . The structural part 9 is a cylindrical section at the first 0.5 meters (blade root to section 11), which is used to embed bolts. The section shape behind section 11 passes through the circle and the maximum chord length section 12 of the blade (the maximum chord length of the blade). The airfoil of each section is obtained by lofting. The aerodynamic component 10 is obtained by setting out the aerodynamic type of the blade root and the airfoil of each section after the maximum chord length section 12 of the blade. 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 components and the maximum chord section 12 of the blade.

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

Referring to Figure 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 not designed by 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 Figure 5, it is a comparison of the thrust coefficient of 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 blades above. 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 (1)

1. A wind turbine blade, which is composed of the front part of the blade and the rear part of the blade. The front part of the blade is the section from the tip part to the maximum chord length of the blade (12), and the rear part of the blade is the section from the maximum chord length of the blade (12) to The blade root part; the rear part of the above-mentioned blade 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) is a cavity between; It is characterized in that the shape of the aerodynamic component (10) transitions from the maximum chord length of the blade to the aerodynamic airfoil (2) of the blade root, and the specific transition form passes through the airfoil of each section at the front of the blade and the aerodynamic airfoil of the blade root (2). Stake out to get; The chord length of the blade root aerodynamic airfoil (2) of the aerodynamic component (10) is greater than the structural chord length of the blade root of the structural component, and smaller than the maximum chord length of the blade; The shape of the above-mentioned blade root aerodynamic airfoil (2) is determined by the following methods: The shape of the blade root aerodynamic airfoil is composed of 5 tangent arcs that are tangent to the structural shape, and the 5 arcs are defined as leading edge upper arc (3), leading edge arc (4), leading edge lower arc arc (5), arc on the trailing edge (7), arc on the trailing edge (6); Among them, the upper arc of the front edge (3) is inscribed with the outer circle of the structural type (1), the lower arc of the front edge (5) is inscribed with the outer circle of the structural type (1), and the arc of the front edge (4) is inscribed with the upper circle of the front edge. Both the arc (3) and the lower arc (5) on the leading edge are inscribed, and the center of the upper arc (6) on the trailing edge is on a straight line passing through the center of the structural type (1) and forming a 60° angle with the neutral line, which is consistent with the structural type (1) The outer circle is inscribed, and the lower arc of the trailing edge. (7) The center of the arc is on the straight line passing through the center of the structural type (1) and forming a -45° with the neutral line, which is outside the outer circle of the structural type (1). cut; the above-mentioned neutral line refers to the center of the structural circle, and is perpendicular to the line connecting the center of the upper arc (3) and the lower arc (5) of the leading edge; The trailing edge thickness (8) is formed at the junction of the trailing edge lower arc (7) and the trailing edge upper arc (6), and the trailing edge thickness (8) is 0.5% to 1% of the diameter of the structural type (1); The relative thickness of the blade root aerodynamic airfoil (2) is less than 100%. 2. A wind turbine blade according to claim 1, characterized in that: The above-mentioned structural component (9) and the front part of the blade are integrated; the above-mentioned aerodynamic component (10) is fixedly connected with the structural component (9) and the front part of the blade at the maximum chord length of the blade. 3. A wind turbine blade according to claim 1, characterized in that: The blade root structure type (1) of the above-mentioned structural component (9) is a circle whose radius is consistent with the radius of the blade root flange.

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