CN106014761B - A kind of self-oscillation aerofoil profile power generator using vortex shedding effect - Google Patents

Abstract

The invention discloses a self-excited oscillating airfoil power generation device using the vortex shedding effect, which is characterized in that it includes a vertically arranged sleeve and blades and a horizontally arranged trunnion capable of swinging around its axis; wherein, the sleeve One end is fixed on the trunnion, the bottom of the blade is inserted into the other end of the sleeve, and the blade can freely rotate in the sleeve along its own axis; one end of the trunnion is connected to the plane scroll spring, and the other end is connected to the power output device connect. The invention provides a self-excited oscillation airfoil power generation device utilizing the vortex shedding effect. The blades in the device have two degrees of freedom independent of each other, and the torsional and rocking motions of the blades are driven by fluid. Among them, the torsional motion of the blade mainly utilizes the vortex shedding effect when the fluid passes through the blunt body, and the swinging motion of the blade mainly utilizes the periodic lift force change of the blade.

Description

A self-excited oscillating airfoil power generation device using vortex shedding effect

Technical field:

The invention relates to a wind power or hydroelectric power generation device, in particular to a self-excited oscillation airfoil power generation device utilizing the vortex shedding effect.

Background technique:

With population growth, economic development and social progress, people's demand for energy, especially clean energy, is increasing. The power generation of traditional hydropower stations and wind turbines has been increasing year by year, but their impact on the environment has also attracted increasing attention. For example, the impact of hydropower stations on upstream and downstream ecology and local landforms, the noise pollution of large wind turbines and their impact on migratory bird migration. The installed capacity of traditional hydropower stations and wind turbines, especially hydropower stations, is gradually approaching their limit values. In this context, conventional water turbines and wind turbines as well as their alternatives or supplements have been developed. Among them, the energy absorption of oscillating airfoil has gradually attracted the attention of the academic circle in recent years, and a comprehensive study has been carried out. Compared with traditional wind turbines, the oscillating airfoil energy-absorbing device has simple structure, low construction cost, small size, and is more environmentally friendly; its application range is also wider, such as rivers, coasts, canyons, etc., which are not suitable for traditional water turbines and wind turbines. Narrow and long fluid area; the oscillating airfoil power generation device can maintain high energy absorption efficiency at different flow velocities, which means it is especially suitable for occasions with low flow velocity and high fluid density such as ocean currents and tides.

Existing oscillating airfoil energy-absorbing mechanisms are mainly translational in the direction perpendicular to the incoming flow, and support structures need to be installed at both ends of the blade, resulting in complex mechanisms and poor adaptability; in addition, special motor-driven wings are required Type torsion, or using mechanisms such as connecting rods and crankshafts to transmit the power of airfoil translation or flapping to the torsion drive mechanism, which not only reduces efficiency, but also increases costs. In this context, the present invention proposes a new type of energy absorbing device that uses the vortex shedding effect of the C-shaped airfoil blade to directly drive the blade to twist, and the generator collects energy from the swing motion of the blade.

Invention content:

The object of the present invention is to provide a self-excited oscillation airfoil power generation device utilizing the vortex shedding effect.

In order to achieve the above object, the present invention is realized by adopting the following technical solutions:

A self-excited oscillating airfoil power generation device utilizing the vortex shedding effect, comprising vertically arranged sleeves and blades and horizontally arranged trunnions that can swing around their axes; wherein,

One end of the sleeve is fixed on the trunnion, the bottom of the blade is inserted into the other end of the sleeve, and the blade can freely rotate in the sleeve along its own axis; one end of the trunnion is connected with the plane scroll spring, and the other end is connected with the PTO connection.

A further improvement of the present invention is that one end of the sleeve is fixed on the trunnion through the shaft end cover.

A further improvement of the present invention lies in that the power output device is a gearbox or a generator.

A further improvement of the present invention is that a thrust bearing is provided between the bottom of the blade and the sleeve, and a radial bearing is provided between the circumference of the blade and the sleeve.

A further improvement of the present invention lies in that two bearings are fitted on the trunnion, and the two bearings are respectively located on both sides of the connection between the sleeve and the trunnion, and the two bearings are respectively installed in a bearing seat, and the The bottoms are all fixed to the base.

The further improvement of the present invention is that the sleeve is provided with a first elastic member along its axial direction, and the blade is provided with two second elastic members along its radial direction, and the blade is subjected to the first elastic member at the maximum angle of torsional movement along its own axis. piece and two second elastic pieces are limited.

A further improvement of the present invention is that one end of the trunnion is provided with a slot along its radial direction, one end of the planar scroll spring is inserted into the slot on the trunnion, and the other end is fixed on the base.

The further improvement of the present invention is that one end of the trunnion is provided with two slots along its radial direction, and the two slots are distributed at 180°, the number of plane scroll springs is two, and the two plane scroll springs are arranged symmetrically .

A further improvement of the present invention is that the blades are C-shaped airfoil blades.

Compared with the prior art, the present invention has the following advantages:

The invention provides a self-excited oscillation airfoil power generation device driven by the vortex shedding effect. The blades in the device have two independent degrees of freedom, and the twisting and swinging motions of the blades are all driven by fluid. Among them, the torsional motion of the blade mainly utilizes the vortex shedding effect when the fluid passes through the blunt body, and the swinging motion of the blade mainly utilizes the periodic lift force change of the blade.

Further, the present invention fixes the elastic rod on the blade and the sleeve, which limits the torsion angle of the blade, so as to control the angle of attack of the incoming flow of the blade and achieve optimal efficiency; at the same time, the elastic rod can store a part of the kinetic energy of the torsion, avoiding Energy loss; in addition, the elastic rod also provides a critical protection mechanism, when the incoming flow velocity is too high, the elastic rod will be broken first, so that the blade can adjust the angle to obtain the minimum windward area, and to a certain extent Protect the main mechanisms of the invention from being damaged.

Furthermore, the present invention uses symmetrically arranged planar scroll springs to determine the balance position of the blades and limit the maximum swing amplitude of the blades. The symmetrically arranged coil springs ensure the symmetry of the spring stiffness, thereby ensuring the symmetry of the blade swing. The non-linear radius change of the coil spring makes the stiffness of the coil spring change non-linearly, and the stiffness of the coil spring increases with the increase of the swing angle of the blade. The nonlinear spring stiffness optimizes the torsional vibration characteristics of the trunnion, so that the present invention can adapt to different incoming flow velocities.

Finally, the present invention designs the cross-section of the blade into a C-shaped airfoil, which can maximize the magnitude of the lift, thereby improving the power and efficiency of the present invention; meanwhile, the C-shaped airfoil blade is also conducive to improving the blade's Overall strength and save blade material.

Description of drawings:

Fig. 1 is the overall structure schematic diagram of the present invention, and wherein, Fig. 1 (a) is overall schematic diagram, and Fig. 1 (b) is partial enlarged schematic diagram, and Fig. 1 (c) is partial sectional view;

Fig. 2 is a schematic diagram of blade torsional movement, wherein Fig. 2(a) is an intermediate state, Fig. 2(b) is a downward movement state, and Fig. 2(c) is an upward movement state;

Fig. 3 is a schematic diagram of a trunnion, a plane scroll spring and their cooperation;

Fig. 4 is a side view of the planar scroll spring.

In the figure: 1 is the trunnion, 2 is the sleeve, 3 is the blade, 4 is the elastic rod, 5 is the first bolt, 6 is the plane scroll spring, 7 is the shaft end cover, 8 is the bearing seat, 9 is the power output Device, 11 is the bearing, 12 is the elastic rod, 13 is the second bolt, 14 is the third stud, 15 is the thrust bearing, 16 is the radial bearing, 17 is the fourth bolt, 18 is the base, I is the flow direction , II is the first direction, and III is the second direction.

Detailed ways:

The present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the present invention utilizes the self-excited oscillation airfoil power generation device of the vortex shedding effect, and the technical scheme adopted in the figure is as follows:

Trunnion 1 is arranged horizontally, sleeve 2 and blade 3 are arranged vertically. The sleeve 2 is fixedly connected with the trunnion 1 through the third stud 14 and the shaft end cover 7 . One end of the blade 3 is inserted into the sleeve 2, and the radial bearing 16 and the thrust bearing 15 cooperate with the blade, so that the blade 3 can freely rotate in the sleeve 2 around its own axis. The trunnion 1 is radially and axially constrained by the bearing 11 and the bearing housing 8 . One end of the trunnion 1 is connected with the planar scroll spring 6, and the other end 9 is connected with mechanisms such as a gearbox and a generator. The trunnion 1 , the sleeve 2 and the vane 3 can form a whole, and perform rocking motion around the axis of the trunnion 1 . When the fluid flows through the blade 3, it will form periodic shedding vortices downstream of the blade 3, and these vortices will form a periodic moment on the blade 3, and this moment will drive the blade to do twisting motion. When the blade 3 performs twisting motion, its angle of attack relative to the incoming flow fluctuates periodically, and the periodic lift causes the blade 3 to periodically swing around the axis of the trunnion. In this process, the kinetic energy of the fluid is firstly converted into kinetic energy of the rotating parts (blades 3, sleeve 2, trunnion 3, etc.). A part of the kinetic energy of the rotating part is converted into the potential energy of the elastic parts (elastic rod 4, planar scroll spring 6), and the other part of the kinetic energy is output as electric energy by the end part 9. The elastic potential energy stored in the elastic rod 4 is used to restore the torsional motion of the blade 3, the elastic potential energy of the planar scroll spring 6 is used to restore the swing motion of the blade 3, and the energy of the elastic components will eventually be output as electrical energy.

The elastic rod 4 is fixed on the sleeve 3 through the first bolt 5, and the elastic rod 12 is fixed on the blade 3 through the second bolt 13, and the positions of the elastic rods 4 and 12 along the circumferential direction can be adjusted. As shown in the top view of FIG. 2 , the section of the blade 3 is approximately C-shaped, and the two ends of the blade face the flow direction I of the fluid. When the blade 3 twists counterclockwise around the axis under the action of the shedding vortex, it will eventually move to state (b) and stop. At this time, the elastic rod 12 is in contact with the elastic rod 4 below, and the kinetic energy of the torsion is converted into an elastic rod. 4, the lift force received by the blade 3 is downward along the first direction II, and the blade 3 has a tendency to swing counterclockwise when viewed from the power generation end 9; on the contrary, when the blade 3 is in the shedding vortex When twisting clockwise around the axis under action, it will eventually move to state (c) and stop. At this time, the elastic rod 12 is in contact with the upper elastic rod 4. At this time, the lift force received by the blade 3 is along the direction of the second direction III Upwards, viewed from the power generation end 9, the blades 3 have a tendency to swing clockwise. The above description illustrates the mechanism of the blade twisting motion and rocking motion, wherein the elastic rods 12 and 4 are used to limit the maximum angle of blade twisting.

FIG. 3 illustrates the cooperative relationship between the trunnion 1 and the planar scroll spring 6 . One end of the planar scroll spring 6 is inserted along the slot opened on the trunnion 1 , and the other end is fixedly connected with the base 18 through the fourth bolt 17 . Two planar scroll springs 6 are connected to the trunnion 1, and the two planar scroll springs 6 have the same structure and are arranged symmetrically. Because the blade 3 needs to swing back and forth, the springs arranged in this way can ensure the symmetry of the torsional stiffness of the trunnion 1, thereby ensuring the symmetry of the swing of the blade. As can be seen from the side view of the plane scroll spring 6 in Fig. 3, the radius of the plane scroll spring 6 does not change linearly, and as the rotation angle of the plane scroll spring 6 increases, the radius of the plane scroll spring 6 is accelerating increase. Therefore, the stiffness of the planar scroll spring 6 is non-linear, and the stiffness of the planar scroll spring 6 increases as the swing angle of the blade 3 increases. This spring makes it easier for the blade 3 to pass through the swinging equilibrium position, and the nonlinear stiffness prevents the torsional natural frequency of the trunnion from concentrating on a certain fixed value, so that the present invention can adapt to different incoming flow velocities.

In addition, as long as the vortex shedding occurs downstream of the blade 3, and the moment of the blade 3 is sufficient to overcome the friction in the rolling bearings 15 and 16, the blade 3 will do twisting and rocking motions by itself, which means that the present invention is very small. Self-starting is possible at flow speeds.

Claims (8)

1. A self-excited oscillating airfoil generating device utilizing the vortex shedding effect is characterized in that it comprises a vertically arranged sleeve (2) and a blade (3) and a horizontally arranged trunnion (1) that can swing around its axis );in, One end of the sleeve (2) is fixed on the trunnion (1), the bottom of the blade (3) is inserted into the other end of the sleeve (2), and the blade (3) can be driven along its own axis under the direct drive of the fluid Freely torsion in the sleeve (2); one end of the trunnion (1) is connected with the plane scroll spring (6), and the other end is connected with the power output device (9); The sleeve (2) is provided with a first elastic member (4) along its axial direction, and the blade (3) is provided with two second elastic members (12) along its radial direction, and the blade (3) is twisted along its own axis The maximum angle of movement is restricted by the first elastic piece (4) and the two second elastic pieces (12). 2. A self-excited oscillating airfoil power generation device utilizing vortex shedding effect according to claim 1, characterized in that one end of the sleeve (2) is fixed on the trunnion (1) through the shaft end cover (7) . 3. A self-excited oscillating airfoil power generation device utilizing vortex shedding effect according to claim 1, characterized in that the power output device (9) is a gearbox or a generator. 4. A kind of self-excited oscillation airfoil power generation device utilizing vortex shedding effect according to claim 1, characterized in that, a thrust bearing (15) is arranged between the bottom of the blade (3) and the sleeve (2), A radial bearing (16) is arranged between the circumferential direction of the blade (3) and the sleeve (2). 5. A self-excited oscillating airfoil generating device utilizing the vortex shedding effect according to claim 1, characterized in that two bearings (11) are also sleeved on the trunnion (1), and the two bearings (11) They are respectively located on both sides of the connection between the sleeve (2) and the trunnion (1), and the two bearings (11) are respectively installed in a bearing seat (8), and the bottom of each bearing seat (8) is fixed on the base on the seat (18). 6. A self-excited oscillating airfoil generating device utilizing the vortex shedding effect according to claim 1, characterized in that one end of the trunnion (1) is provided with a slot along its radial direction, and the plane scroll spring (6 ) is inserted in the slot on the trunnion (1), and the other end is fixed on the base (18). 7. A self-excited oscillating airfoil generating device utilizing vortex shedding effect according to claim 6, characterized in that, one end of the trunnion (1) is provided with two slots along its radial direction, and the two slots The slits are distributed at 180°, the number of plane scroll springs (6) is two, and the two plane scroll springs (6) are arranged symmetrically. 8. A self-excited oscillating airfoil power generating device utilizing vortex shedding effect according to claim 1, characterized in that the blade (3) is a C-shaped airfoil blade.