CN102022259A - Lift-to-drag blending wing plate type vertical axis wind wheel - Google Patents

Abstract

The invention discloses a lift-to-drag blending wing plate type vertical axis wind wheel, comprising a rotating shaft and a plurality of blades which are distributed along the periphery and take the rotating shaft as the center. Each blade is a lift-to-drag blending wing plate which is formed by integrally blending a lift convex surface and a resistance concave surface, and the combining part of the convex surface and the concave surface of the blade is provided with transition arc cylinder surfaces which can be matched mutually. The wind wheel combines the characteristics of drag and lift of the wind power utilization, has the advantages of low starting wind speed, fast speed increasing, high wind energy use ratio, low cost and the like, and is reliable in operation.

Description

Lift-drag blended vane type vertical axis wind rotor

technical field

The invention relates to a vertical-axis wind rotor for wind power generation, in particular to a vane-type vertical-axis wind rotor with combined lift and drag functions.

Background technique

Wind energy is a clean, safe, and renewable green energy that is inexhaustible and inexhaustible. It has gradually become a new energy that is vigorously developed and utilized by countries all over the world. Wind turbines can be divided into two categories: horizontal axis wind turbines and vertical axis wind turbines. The structural feature of the horizontal axis wind turbine is that the rotation plane of the wind rotor is perpendicular to the wind direction, and the rotation axis is parallel to the ground. It is currently the most mature technology and the most widely used wind turbine. The vertical axis wind turbine is characterized by the fact that the rotation axis is perpendicular to the ground, and the rotation plane of the wind rotor is parallel to the wind direction. It has the advantages of simple wind turbine tower structure, convenient operation and maintenance, low blade manufacturing cost, and no windward device. It can be divided into There are two types of lift wind rotors and drag wind rotors. The typical lift-type wind rotor is Darrieus type wind turbine. According to the shape of the blade, the Darrieus type fan has various forms such as Φ type, △ type, H type, Y type and ◇ type. It has high speed , large rotational inertia, simple structure, etc., but the starting torque is small and the starting performance is poor. When the tip speed ratio (blade tip speed/wind speed) is less than 3.5, it is difficult to start, and it needs to consume other energy to start the wind wheel . The typical drag-type wind wheel is the S-shaped Savonius Type wind turbine, which has the advantages of simple structure, low cost, large turning torque, and good starting performance, but the speed and efficiency are low. The tip speed ratio is always less than 1.

In view of the characteristics and deficiencies of the above-mentioned lift-type and drag-type vertical-axis wind rotors, there are some solutions in the prior art. For example, "a lift-drag complementary vertical-axis wind rotor" disclosed in Chinese Patent Publication No. A set of spiral resistance blades are installed inside the Φ-type lift wind wheel, and the lift type wind wheel and the resistance type wind wheel are assembled into a composite function wind wheel by mechanical combination to convert wind energy into mechanical energy. This type of wind wheel uses two The blades with different structures are arranged inside and outside, which is complex in structure and difficult to manufacture. Another example is the "windmill for wind power generation" disclosed in Chinese Patent Publication No. CN100347440C, which is a part of the trailing edge of the lift vane (low Reynolds number and high lift coefficient) blade of the Darius type H-type wind wheel. The improved wing blade with the cross-sectional shape of "hollow comma" is cut off to achieve the comprehensive effect of the lift type wind rotor and the drag type wind rotor, but the cut part of the wind rotor blade damages the overall shape of the blade structure and is The underside of the airfoil forms a bluff surface which is not conducive to the flow of wind there.

Contents of the invention

The object of the present invention is to provide a vertical axis wind rotor with simple structure and better utilization of wind energy.

The technical solution of the present invention is a lift-drag fusion wing plate type vertical axis wind wheel, which includes a rotating shaft and a plurality of blades distributed along the circumference around the rotating shaft, and each blade is the same as the height extension direction of the surrounding sides and the rotating shaft axis. The shape of the cross section perpendicular to the axis of rotation is an airfoil-shaped lift-drag fusion wing plate. The surrounding sides of the blade are composed of a lift convex cylinder, a drag concave cylinder, and a front end connected to the lift convex cylinder and the drag The front transition arc cylinder between the front ends of the concave cylinders and the rear transition arc cylinder connected between the rear end of the lift convex column panel and the rear end of the drag concave column panel are enclosed; the lift convex cylinder is formed by the front 1. The last two sections of circular arc cylinder are smoothly transitioned and connected, and the resistance concave cylinder is composed of a section of arc cylinder.

The cross section of the blade is determined based on the airfoil parameters of the blade. The airfoil parameters are obtained from the chord line and the chord length, and the maximum distance between the front transition arc cylinder and the rear transition arc cylinder of the blade is located The line segment is defined as the chord line, the length of the chord line is the chord length of the blade, and the airfoil parameters are as follows: the radius of the front circular arc cylinder segment of the lift convex surface is 28.5% of the chord length, the arc angle is 72°, and the rear arc cylinder The radius of the surface segment 112 is 126% of the chord length, and the arc angle is 35°. The radius of the arc cylinder of the resistance concave surface is 126% of the chord length, and the arc angle is 46°. The radius of the surface 13 is 1.5% of the chord length, the radius of the trailing edge transition arc cylinder 14 is 1% of the chord length, and the maximum distance between the lift convex surface and the resistance concave surface is defined as the maximum arch thickness of the blade, the maximum arch thickness is 15% of the chord length, the curve in the cross-section of the blade that is equal to the distance between the lift convex surface and the drag concave surface is defined as the mid-arc, and the maximum distance between the mid-arc and the chord is defined as the maximum camber of the blade, and the maximum camber 16.5% of the chord length.

When the blades are installed, there is an installation angle between the chord line of the blade and the line connecting the front end point of the chord line and the center of the rotating shaft, and the installation angle is 60° to 70°. The connection line of the blades is arranged on the circumference according to the equal division angle; the diameter of the circumference where the outermost ends of the blades are located is the outer diameter of the wind rotor, and the outer diameter of the wind rotor is 286% of the chord length.

The ratio of the height of the blades of the wind rotor to the diameter of the outer circle of the wind rotor, that is, the ratio of height to diameter, is 1-3.

The upper and lower ends of each blade are fixedly connected to the circular upper cover plate and the lower base plate which are vertically intersected with the rotation axis, and the outer circle diameter of the upper cover plate and the lower base plate is the same as the outer circle of the wind wheel. equal in diameter. the

The blade of the present invention is a lift-drag fusion wing plate. The lift convex surface of the blade presents the characteristics of the lift blade wind wheel at a suitable angle of attack (the angle between the chord line and the airflow direction), while the drag concave surface of the blade is realized at different positions. The function of the resistance blade wind wheel, because the lift-drag fusion wing plate blade can generate both lift and resistance to drive the wind wheel under the action of the wind, and the existing lift-drag complementary vertical axis wind wheel (CN101566126A) Compared with the combined structure, starting from the components of the blade itself, the lift and resistance functions are integrated, so that the structure is simple, the cost is low, and the operation is reliable; and the resistance concave surface of the blade of the present invention is an arc cylinder, which is different from the existing rear The windmill for wind power generation (CN100347440C) formed by blades with notched parts forms a smoother air flow structure than when the concave surface faces the wind, which is beneficial to improving the wind energy utilization characteristics. The lift-drag fusion wing plate wind wheel involved in the present invention has the characteristics of large driving torque and low starting wind speed of the resistance type wind wheel when running at low speed, and the speed ratio of the blade tip is higher than that of the traditional resistance type wind wheel. The low-speed start-up performance of the lift-type wind wheel is not good enough. In the case of high-speed operation, the lift-drag fusion blade wind rotor has the characteristics of high speed and high wind energy utilization rate of the lift-type wind rotor, and at the same time improves the weakness of the resistance-type wind rotor at low operating speed. In this way, the lift-drag fusion wing plate wind rotor takes into account the low-speed performance of the resistance-type wind rotor and the high-speed performance of the lift-type wind rotor, and extends the high-efficiency characteristics of converting wind energy into mechanical energy to the entire working wind speed range of 1.6-30m/s, improving The wind energy conversion efficiency of the wind rotor.

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Description of drawings

Fig. 1 is a schematic diagram of the wing plate installation layout of a specific embodiment of the wind wheel of the present invention (the upper cover plate and the lower bottom plate are not shown);

Fig. 2 is the geometric structure diagram of the wing plate cross-section in Fig. 1;

Fig. 3 is a structural schematic diagram of the assembly of the wind wheel and the fan in Fig. 1 .

In the figure: 1. blade; 2. upper cover plate; 3. sealing cover; 4. rotating shaft; 5. lower base plate; 6. outer rotor permanent magnet generator.

Detailed ways

As shown in Figures 1 to 3, the specific embodiment of the vertical axis wind wheel of the present invention includes a rotating shaft 4 and five blades 1 distributed along the circumference with the rotating shaft 4 as the center, and the upper and lower ends of each blade 1 are respectively connected to On the upper cover plate 2 and the lower base plate 5 which are vertically intersected with the rotation shaft 4 and fixedly connected, the upper and lower ends of each blade 1 are fixed on the corresponding upper cover plate 2 and lower base plate 5 by bolts, and the wind force received by the blade 1 It is transmitted to the rotating shaft 4 through the upper cover plate 2 and the lower base plate 5 . Each blade 1 is an airfoil-shaped lift-drag fusion wing plate whose height extension direction of the surrounding side is consistent with the axis of the rotating shaft 4 and whose cross-section is perpendicular to the rotating shaft 4. The surrounding side of the blade 1 is formed by a lift convex surface Cylinder 11, resistance concave cylinder 12, front transition arc cylinder 13 connected between the front end of lift convex cylinder 11 and resistance concave cylinder 12, connected to the rear end of lift convex cylinder panel 11 and resistance concave column panel The rear transition arc cylinder 14 between the rear ends of the 12 is enclosed, the lift convex cylinder 11 is formed by the smooth transition connection of the front and rear two arc cylinder sections 111, 112, and the resistance concave cylinder 12 is It is composed of a section of arc cylinder, so the side of the blade 1 is composed of multiple sections of arc cylinder, the structure is simple, the design and manufacture are convenient, and the lift-drag fusion wing plate wind wheel takes into account the low-speed performance of the resistance type wind wheel and the lift-type wind turbine. high-speed performance of the wheel. the

Further, the line segment where the maximum distance between the front transition arc cylinder 13 and the rear transition arc cylinder 14 of the blade 1 is defined as the chord line, the chord line is represented by c in FIG. 2 , and the length of the chord line is The chord length L of blade, in the embodiment of the present invention, the airfoil parameter of blade 1 obtains based on the chord length of blade, the airfoil of the blade 1 of the wind wheel of the present invention is the cross-sectional shape as shown in Figure 2, chord length L directly related to leaf size. The airfoil parameters are as follows: the radius _R1 of the front arc cylinder section 111 of the lift convex surface 11 is 28.5% of the chord length, the arc angle _β1 is 72°, and the radius _R2 of the rear arc cylinder section 112 is the chord length. Long 126%, arc angle β ₂ is 35 °, the radius R ₃ of the arc cylinder of the resistance concave surface 12 is 126% of the chord length, arc angle β ₃ is 46 °, the leading edge transition arc column The radius _R4 of the surface 13 is 1.5% of the chord length, the radius _R5 of the trailing edge transition arc cylinder 14 is 1% of the chord length, and the maximum distance between the lift convex surface 11 and the resistance concave surface 12 is defined as the maximum The arch thickness is T, and the maximum arch thickness is 15% of the chord length. The curve in the cross section of the blade 1 that is equal to the distance from the lift convex surface 11 and the resistance concave surface 12 is defined as the middle arc, and the middle arc is represented by b in Figure 2. The maximum distance between the center arc and the chord line is defined as the maximum camber f of the blade, and the maximum camber is 16.5% of the chord length. After the chord length is selected, the above airfoil parameters can be combined to design the Cross-section of the invented blade.

Further, in order to make the blades in the wind rotor of the present invention better exhibit the characteristics of the lift-drag fusion wing in the wind field, the blades 1 in the embodiment of the present invention are composed of the blade layout according to the assembly relationship shown in Figure 1 , so that there is an installation angle α between the chord line c of each blade 1 and the line connecting the front end point of the chord line and the center O of the rotating shaft 4, the installation angle α of the blade 1 is selected from 60° to 70°, and the chord line of each blade 1 The connecting line between the front end point of the line and the center of the rotating shaft is arranged on the circumference according to the equal division angle. In this way, the lift convex surface of the blade 1 has an angle of attack (the angle between the chord line and the airflow direction) of 40° to 50°, so that the blade 1 exhibits the characteristics of the lift blade rotor and has the same power as the lift blade rotor when rotating. The tip speed ratio, and the resistance concave surface of the blade realizes the function of the resistance blade wind wheel at different positions. And the diameter of the circumference of the outermost end of each blade 1 in Fig. 2 is D _max , the outer circle diameter of the upper cover plate 2 and the lower bottom plate 5 in the embodiment of the present invention is also D _max , and the height of the blade 1 is H, and the solidity ratio L/D _max of the blade chord length section area L×H in the swept area D _max ×H of the wind rotor is 0.35, so it can be obtained that D _max is 286% of the chord length. Through the above configuration, the wind rotor of the present invention has a large driving torque and a small start-up wind speed in the low-speed working area, which reflects the advantages of the resistance-type wind wheel; while in the high-speed working area, the high speed and high wind energy utilization rate also reflect the Advantages of lift-type wind rotors. It not only overcomes the difficulty of starting the lift-type wind rotor, but also makes up for the defect of the poor speed characteristics of the resistance-type wind rotor, so that the efficiency characteristics of converting wind energy into mechanical energy are extended to the entire working wind speed range of 1.6-30m/s, thereby improving the performance of the wind rotor. Overall wind energy conversion efficiency.

In order to make the wind rotor of the present invention obtain better utilization rate of wind energy in the wind field, the wind rotor in the embodiment of the present invention selects the outer circle diameter D _max of the wind rotor and the height H of the blade according to the location of the wind field and the power of the fan. The ratio, that is, the height-to-diameter ratio H/D _max is 1 to 3, whereby the blade height can be obtained.

Figure 3 is a schematic diagram of the assembly structure of the vertical axis wind wheel and wind power generation device of the present invention, the center of the upper cover plate 2 is equipped with a radial ball bearing, and the center of the lower base plate 5 is equipped with a centripetal thrust cylindrical bearing . The sealing cover 3 on the top of the fan and the upper cover plate 2 are fixedly connected by bolt components. The lower bottom plate 5 and the outer rotor permanent magnet generator 6 are fixedly connected by another set of bolt assemblies through corresponding flanges.

The blade 1 in the above-mentioned embodiment of the present invention is a solid column structure, while the blade 1 in other embodiments of the present invention can be surrounded by a lift convex panel, a drag concave panel, and a front and rear transition arc column panel. A hollow structure with vertical and horizontal ribs is formed in the middle, but its airfoil parameters remain unchanged.

The number of blades in the above embodiments of the present invention may also be three, four, or more than six.

In the above-mentioned embodiments of the present invention, the blade 1 and the rotating shaft are fixedly connected by two upper and lower plates-the upper cover plate and the lower bottom plate to form a wind wheel. The radially extended support arm is used to fix the blade 1 to form a wind rotor. The wind force received by the blade 1 is transmitted to the rotating shaft 4 through the support cantilever. In the wind rotor connected to the blade 1 by the support arm, the selected chord length , installation angle, height-to-diameter ratio and solidity ratio to design the length of the support arm and the connection position between the support arm and the blade 1 .

Claims (5)

1. Lift-drag fusion vane type vertical axis wind rotor, including a rotating shaft and a plurality of blades distributed along the circumference around the rotating shaft, characterized in that: the height extension direction of each blade is the same as the axial direction of the rotating shaft, And the shape of the cross section perpendicular to the axis of rotation is an airfoil-shaped lift-drag fusion wing plate. The surrounding sides of the blade are composed of a lift convex cylinder, a resistance concave cylinder, and are connected to the front end of the lift convex cylinder and the resistance concave cylinder. The front transition arc cylinder between the ends and the rear transition arc cylinder connected between the rear end of the lift convex column panel and the rear end of the drag concave column panel are enclosed; the lift convex cylinder is composed of the front and rear two The circular arc cylindrical surface is composed of a smooth transition connection, and the resistance concave cylindrical surface is composed of a circular arc cylindrical surface. 2. The wind rotor according to claim 1, characterized in that: the cross section of the blade is determined based on the airfoil parameters of the blade, the airfoil parameters are obtained from the chord line and the chord length, and the front transition arc of the blade is The line segment where the maximum distance between the cylinder and the rear transition arc cylinder is defined as the chord line, the length of the chord line is the chord length of the blade, and the airfoil parameters are as follows: the radius of the front arc cylinder segment of the lift convex surface is 28.5% of the chord length, the arc angle is 72°, the radius of the back arc cylinder section 112 is 126% of the chord length, and the arc angle is 35°, the radius of the arc cylinder of the resistance concave surface is 126% of the chord length %, the arc angle is 46 °, the radius of the leading edge transition arc cylinder 13 is 1.5% of the chord length, the radius of the trailing edge transition arc cylinder 14 is 1% of the chord length, and the lift convex surface and the resistance concave surface The maximum distance between them is defined as the maximum arch thickness of the blade, and the maximum arch thickness is 15% of the chord length. The curve in the cross-section of the blade is defined as the mid-arc, the mid-arc and the chord The maximum distance between the lines is defined as the maximum camber of the blade, which is 16.5% of the chord length. 3. The wind wheel according to claim 2, characterized in that: when the blades are installed, there is an installation angle between the chord line of the blade and the line connecting the front end point of the chord line and the center of the rotating shaft, and the installation angle is 60°～70°, the line connecting the front end point of the chord line of each blade and the center of the rotating shaft is arranged on the circle according to the equal angle; the diameter of the circle where the outermost end of each blade is located is the outer diameter of the wind wheel, The outer diameter of the wheel is 286% of the chord length. 4 . The wind rotor according to claim 3 , wherein the ratio of the height of the blades of the wind rotor to the diameter of the outer circle of the wind rotor, that is, the ratio of height to diameter, is 1-3. 5 . 5. The wind wheel according to claim 4, characterized in that: the upper and lower ends of each blade are fixedly connected to a circular upper cover plate and a lower bottom plate which are perpendicular to the rotation axis and fixedly connected to each other. The outer circle diameters of the upper cover plate and the lower bottom plate are equal to the outer circle diameters of the wind wheel.

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