CN101672245B - Horizontal-shaft wind turbine with rotating cylinder at front edge of paddle - Google Patents

Abstract

The invention relates to a horizontal axis wind turbine with a rotating cylinder at the leading edge of the blade. It consists of a vertically mounted tower, a horizontal axis chassis mounted on top of the tower, and a blade and hub or shroud at the front of the chassis. Each blade leading edge is equipped with a controllable cylinder that rotates positively or reversely around its own axis, and the rotating cylinder and the blades revolve around the rotor in the random box together. By adjusting the rotation speed and direction of the rotating cylinder, the flow separation of the airflow on the blades is controlled, and the lift-to-drag ratio of the blades of the wind turbine is improved, so as to achieve the purpose of effectively utilizing wind energy.

Description

Horizontal axis wind turbine with rotating cylinder at the leading edge of the blades

technical field

The invention relates to a wind power machine, in particular to a horizontal axis wind power machine with a rotating cylinder at the leading edge of the blade, which can improve the utilization rate of wind energy of the wind power machine.

technical background

At present, the airfoils of horizontal axis wind turbines are mainly selected from aviation airfoils. In order to improve the efficiency of the blades in absorbing wind energy, airfoils with a high lift-to-drag ratio are generally used, and the blades are twisted along the height. When the speed of the wind turbine is constant, as the wind speed increases, the angle of attack of the airflow on the blade also increases, until the airflow separates on the surface of the blade, the blade stalls, the wind energy absorption rate drops sharply, and the output power also rapidly reduce. Wind turbines generally have a set of control systems to adjust the output power and speed. The manufacturing cost of variable pitch wind turbines is high, and there are still few manufacturers of pitch turbines. The fixed-pitch wind turbine adapts to the change of wind speed by adjusting the speed of the wind turbine to increase the lift and increase the absorption rate of wind energy. Under the limitation of a certain rotational speed of the wind rotor, the fixed-pitch wind turbine is more likely to stall with the increase of the incoming wind speed. After the airfoil of the wind turbine is selected, when the wind speed is constant, the maximum lift-to-drag ratio of the airfoil of the fixed-pitch wind turbine is also limited, and it cannot capture as much wind energy as possible.

Contents of the invention

The object of the present invention is to propose a horizontal axis wind turbine with a rotating cylinder at the leading edge of the blades to improve the utilization rate of wind energy of the wind turbine.

In order to achieve the above object, the idea of the present invention is: the airfoil with the rotating cylinder at the leading edge can greatly increase the lift coefficient and reduce the drag coefficient. The rotation speed can well control the flow separation on the surface of the airfoil and effectively improve its lift-to-drag ratio, see Figure 4. References: V.J.MODI, MovingSurface Boundary-Layer Control (moving surface boundary layer control).

However, so far, the above-mentioned airfoils with rotating cylinders at the leading edge only do translational motions in the flow field. If this airfoil with rotating cylinders at the leading edge is applied to a horizontal axis wind turbine, it will be possible to improve the wind power of the airfoil. The lift-to-drag ratio of the model controls the flow separation of the airflow on the surface of the blade, thereby increasing the absorption efficiency of wind energy.

According to above-mentioned inventive concept, the present invention adopts following technical scheme:

A horizontal-axis wind turbine with a rotating cylinder at the leading edge of the blades, comprising a vertically installed tower, a horizontal-axis chassis mounted on the top of the tower, blades and hubs or a shroud at the front end of the chassis. The front edge of each blade is equipped with a controllable cylinder that rotates forwardly or reversely around its own axis, and the rotating cylinder and blades revolve around the horizontal axis of the wind turbine together with the rotor in the hub or the chassis.

The diameter of the above-mentioned rotating cylinder is 0.05-1.5 times the chord length of the airfoil section of the blade, and there is a gap of about 0.0001-0.2 times the diameter of the cylindrical section between the blade and the rotating cylinder.

The above-mentioned rotating cylinder is driven by a motor installed on the hub or the inner rotor of the chassis to rotate in a forward or reverse direction, and the linear velocity U _C on the surface of the cylinder is 0 to 10 times the incoming wind speed U.

The above-mentioned paddles are rotationally connected with the rotating cylinder through several bearings and bearing sleeves to ensure that the relative positions of the paddles and the rotating cylinder in the chord and radial directions remain within the original range; the bearing sleeves are firmly connected with the paddles, and the rotating cylinder and the bearing Bearings are embedded between the sleeves.

The above-mentioned rotating cylinder and the paddle are rotationally connected by 2 to N bearings, N is a natural number greater than 2, and the bearings are deep groove ball bearings or angular contact ball bearings.

Compared with the prior art, the present invention has the following obvious substantive outstanding features and remarkable advantages: the wind turbine proposed by the present invention can adjust the rotational speed of the rotating cylinder at the leading edge of the blade within the available wind speed range, and increase the speed of the blade. The lift-to-drag ratio of the blade can effectively improve the utilization rate of wind energy; when the wind speed is too high, the rotating cylinder stops rotating or rotates in the opposite direction, so that the blade stalls and achieves the purpose of controlling the power output of the wind turbine, which is equivalent to changing the pitch of the wind turbine. The effect of blade angle of attack.

Description of drawings

Figure 1 is a schematic structural view of a horizontal axis wind turbine with a rotating cylinder at the leading edge of the blade.

Fig. 2 is a structural schematic diagram of a small and medium-sized horizontal-axis wind turbine with rotating cylinders on the leading edge of the blades with a tail rudder steering device.

Fig. 3 is a sectional view of a section of a blade of a horizontal axis wind turbine with a rotating cylinder at the leading edge of the blade, in which (a) is a section of the blade, and (b) is a sectional view of A-A.

Figure 4 is a streamline diagram of the airfoil with a rotating cylinder at the leading edge at a certain angle of attack (20°) on the surface of the rotating cylinder at different speeds.

Fig. 5 is a sectional view of the connection between the paddle and the rotating cylinder, in which (a) is an outline view, and (b) is a sectional view at B-B.

Fig. 6 is a schematic diagram of the connection between the paddle and the rotating cylinder.

Fig. 7 is a schematic diagram of the connection between the blade root of the wind turbine and the rotor in Fig. 2 .

Fig. 8 is a schematic diagram of the blade root of the wind turbine in Fig. 1 and a cross-sectional view of the bearing installation at the blade root, wherein Fig. (b) is a cross-sectional view at C-C in Fig. (a).

Fig. 9 is a schematic diagram of forward rotation of the rotating cylinder at the leading edge of the blade and airflow attachment on the surface of the airfoil within the available wind speed range.

Fig. 10 is a schematic diagram of the reverse rotation of the rotating cylinder at the leading edge of the blade and the stalling of the airfoil surface when the wind speed is too high.

Detailed ways

Embodiment 1: Referring to Fig. 1, the horizontal axis wind turbine with a rotating cylinder at the leading edge of the blade includes a tower 5, a horizontal axis chassis 4 installed on the top of the tower 5, a hub 3 located at the front end of the chassis 4 and fixedly installed on the The blades 1 on the hub 3, each blade 1 front edge is equipped with a controllable rotating cylinder 2 that rotates forward or in the same direction around its own axis, and the rotating cylinder 2 and the blades 1 go around the wind turbine with the hub 3 Horizontal axis rotation.

Embodiment 2: Referring to Fig. 2, the horizontal axis wind turbine with a rotating cylinder at the leading edge of the blades includes a vertically installed tower 5, a horizontal axis chassis 4 installed on the top of the tower 5, and a horizontal axis chassis 4 located at the rear of the chassis 4. Tail boom 7 and empennage 8, blade 1 and shroud 6 positioned at the front end of chassis 4, each blade 1 leading edge is equipped with a controllable rotating cylinder 2 that rotates positively or reversely around its own axis, and The rotating cylinder 2 and the blade 1 rotate around the horizontal axis of the wind turbine together with the rotor 14 in the box 4 .

In Figures 1 and 2, there is a certain gap δ between the blade 1 and the rotating cylinder 2 at its leading edge. δ is about 1 mm to 2 cm, depending on the size of the wind turbine, so as to ensure that the rotating cylinder 2 independently rotates around its own axis relative to the blade 1, as shown in the section view of the partial blade 1 in Fig. 3 . In Fig. 1, the paddle 1 and the rotating cylinder 2 are connected through the hub 3 and the drive shaft in the chassis 4, and the root of the paddle 1 gradually transitions into a cylinder to increase the structural strength and rigidity of the joint with the hub 3. At the joint between the root of the paddle 1 and the hub 3, a bearing 9 is installed between the rotating cylinder 2 and the paddle 1, as shown in FIG. 8 . The rotating cylinder 2 is driven by the motor 15 in the hub 3 and can rotate at a certain speed forward or reverse. In FIG. 2 , the blades 1 of the wind turbine are directly connected to the rotor 14 , and each rotating cylinder 2 is driven by an electric motor 15 to rotate in the forward or reverse direction, as shown in FIG. 7 . The steering device that has tail rod 7 and empennage 8 to form makes wind turbine face the wind. In Figures 1 and 2, the wind turbine blade 1 and the bearing sleeve 10 are fixedly connected by bolts 11, and the bearing 9 is embedded between the bearing sleeve 10 and the rotating cylinder 2 to ensure that the rotating cylinder 2 revolves around the horizontal axis of the wind wheel with the blade 1. At the same time, it can rotate around the axis of the cylinder itself, and at the same time ensure that the gap δ between the blade 1 and the rotating cylinder 2 remains unchanged under various loads of the wind turbine, and at the same time improve the overall stiffness of the blade 1 and the rotating cylinder 2. The rotating cylinder 2 can be a stepped shaft, or it can be divided into sections, and each section of the shaft is connected by a key 12 and a fixing screw 13, as shown in FIG. 6 . From the root to the tip end of the blade 1 and the rotating cylinder 2, such a connection consisting of a bearing 9 and a bearing sleeve 10 is arranged at intervals, as shown in FIG. 5 . When the wind speed is small and within the available wind speed range, the motor 15 drives the rotating cylinder 2 to rotate in the forward direction, increasing the lift-to-drag ratio of the blades so that the wind wheel can effectively absorb wind energy, as shown in FIG. 9 . When the wind speed is too high and the generator is overloaded, the motor 15 drives the rotating cylinder 2 to rotate in reverse, so that the blade 1 stalls, and the power output of the wind turbine is controlled, as shown in FIG. 10 .

Claims (3)

1. A horizontal-axis wind turbine with a rotating cylinder at the front edge of the blade, comprising a vertically installed tower (5), a horizontal-axis chassis (4) installed on the top of the tower (5), and a chassis (4) ) paddle (1) and hub (3) or shroud (6) at the front end, characterized in that the front edge of each paddle (1) is equipped with a controllable forward or reverse A rotating cylinder (2), and the rotating cylinder (2) and the blade (1) rotate around the horizontal axis of the wind turbine with the rotor (14) in the hub (3) or the cabinet (4); the blade (1) Several bearings (9) and bearing sleeves (10) are rotationally connected to the rotating cylinder (2) to ensure that the relative positions of the blade (1) and the rotating cylinder (2) in the chord and radial directions remain at the original position Within the range; the bearing sleeve (10) is fixedly connected with the blade (1), and the bearing (9) is embedded between the rotating cylinder (2) and the bearing sleeve (10); the rotating cylinder (2) and the blade (1) ) are rotationally connected by 2 to N bearings (9), where N is a natural number greater than 2, and the bearings (9) are deep groove ball bearings or angular contact ball bearings. 2. The horizontal axis wind turbine with a rotating cylinder at the leading edge of the blade according to claim 1, characterized in that the diameter of the rotating cylinder (2) is 0.05 to 1.5 of the chord length of the blade (1) section airfoil. times, a gap δ of 0.0001 to 0.2 times the cross-sectional diameter of the cylinder (2) is left between the paddle (1) and the rotating cylinder (2). 3. The horizontal axis wind turbine with a rotating cylinder at the leading edge of the blade according to claim 1, characterized in that the rotating cylinder (2) consists of a rotor (14) mounted on the hub (3) or the casing (4). ) on the motor (15) drives forward or reverse rotation, and the surface linear velocity U _C of the cylinder (2) is 0 to 10 times of the incoming wind velocity U.

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