An omnidirectional wind energy capture device based on spherical vortex-induced vibration

Abstract

The present invention discloses an omnidirectional wind energy capture device based on spherical vortex-induced vibration. The spherical oscillation device structure adopted has a larger vibration amplitude than the blunt body structure with a conventional cross-sectional shape. When the airflow acts on the capture device, the oscillation device will generate self-excited vibration, causing the spring to deform, thereby driving the piezoelectric beam to undergo periodic bending deformation. The stress on the piezoelectric beam alternately increases and decreases. Due to the piezoelectric effect, the piezoelectric beam will generate an electric potential difference, thereby converting the vibration energy into electrical energy output. The wind energy capture device provided by the present invention can generate flow-induced vibration response to winds of different directions in the natural environment, can collect fluid energy in all directions, improve energy capture efficiency, and increase the utilization rate of wind energy. It has a simple structure, is easy to assemble, and has a small size. It has strong environmental adaptability and can partially replace the use of batteries.

Description

Technical Field

[0001] The present invention belongs to the field of wind power generation, and more specifically, relates to an omnidirectional wind energy capture device based on vortex-induced vibration of a sphere. Background Art

[0002] With the rapid development of wireless sensor networks (WSNs) and microelectromechanical systems (MEMS), wireless sensors still rely on traditional chemical batteries for energy supply. This energy supply method is difficult to implement in some special environments, such as forests, mountains, and oceans, and it also causes severe environmental pollution and is costly. Meeting the application needs of wireless sensors in natural conditions is a key issue in their development. As a widely available clean energy source in nature, the effective utilization of wind energy has been a key research topic both domestically and internationally. Using transverse flow-induced vibration piezoelectric energy harvesting technology to replace traditional chemical batteries for energy supply has great potential for the self-powered design of MEMS and wireless sensor systems. Wind-induced vibration-based wind energy harvesting devices utilize the structure's vortex-induced vibration, flutter, galloping, and wake galloping to harvest wind energy. Compared with electromagnetic and electrostatic methods, piezoelectric methods offer advantages such as simple structure, high system integration, high power density, low cost, and miniaturization.

[0003] In actual engineering application environments, wind direction and wind speed are random and unstable. Therefore, the research on multi-directional wind energy capture is a top priority in the field of wind energy capture device research and is of great significance to the development of wind energy resources. The Chinese invention patent with publication number CN104779766B discloses a vibration structure and a wind energy capture device for constructing a wind energy capture device. The U-shaped vibration part will produce different vibration responses under the action of wind with different incoming flow speeds and directions, effectively increasing the wind direction and wind speed range of the wind energy capture device. Although this device has achieved multi-directional wind energy capture to a certain extent, it only has the best output power under the action of specific wind directions and wind speeds, and its structure is complex. The Chinese invention patent with publication number CN 112751506 A discloses an omnidirectional wind energy capture device. The oscillation device of the square column, cylindrical column, and "X" shaped column responds similarly to the cantilever beam vibration, driving the piezoelectric ceramic tube to vibrate. The piezoelectric ceramic tube is subjected to periodic vibration and outputs electrical energy, thereby realizing the collection of multi-directional wind energy. However, this device has low wind energy capture efficiency and a complex structure. Currently, most piezoelectric wind energy capture devices in actual projects use a rectangular thin-sheet cantilever beam structure, which has obvious shortcomings in the field of multi-directional wind energy capture. Summary of the Invention

[0004] In response to the above defects or improvement needs of the prior art, the present invention provides an omnidirectional wind energy capture device based on vortex-induced vibration of a sphere, thereby solving the technical problems of the existing wind direction capture device having a complex structure and low wind energy capture efficiency.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an omnidirectional wind energy capture device based on spherical vortex-induced vibration, comprising: a fixed bracket, a spherical oscillating device, a piezoelectric beam and a support;

[0006] The spherical oscillating device is connected to the upper end of the fixed bracket and the piezoelectric beam through upper and lower springs respectively;

[0007] One side of the piezoelectric beam is provided with a sliding groove, which forms a linear guide mechanism with a fixing member provided on the support, and the other side is fixedly connected to the support;

[0008] The lower end of the support is fixedly connected to the lower end of the fixing bracket.

[0009] According to another aspect of the present invention, there is provided an omnidirectional wind energy capture device based on spherical vortex-induced vibration, comprising: a fixed bracket, a spherical oscillating device, a piezoelectric beam and a support;

[0010] The spherical oscillating device is connected to the upper end of the fixed bracket and the piezoelectric beam through upper and lower springs respectively;

[0011] Sliding grooves are provided on both sides of the piezoelectric beam, and they respectively form a linear guide mechanism with the fixing parts provided on the support;

[0012] The lower end of the support is fixedly connected to the lower end of the fixing bracket.

[0013] Preferably, the piezoelectric beam includes a beam and a piezoelectric sheet adhered to the beam.

[0014] Preferably, the spherical oscillating device is made of foam plastic.

[0015] Preferably, the upper and lower ends of the fixing bracket are connected by at least one supporting shaft.

[0016] Preferably, the upper and lower ends of the fixing bracket are connected by a plurality of evenly distributed support shafts.

[0017] Preferably, the support shaft is made of tungsten steel.

[0018] Preferably, the upper end of the fixing bracket is connected to the upper spring through a steel frame.

[0019] Preferably, the upper and lower ends of the fixing bracket and the support are made of nylon.

[0020] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0021] 1. The omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by the present invention adopts a spherical oscillation device structure with a larger vibration amplitude than the blunt body structure with a conventional cross-sectional shape. When the airflow acts on the capture device, the oscillation device will generate self-excited vibration, causing the spring to deform, thereby driving the piezoelectric beam to undergo periodic bending deformation. The stress on the piezoelectric beam alternately increases and decreases. Due to the piezoelectric effect, the piezoelectric beam will generate an electric potential difference, thereby converting the vibration energy into electrical energy output; the wind energy capture device provided by the present invention can generate flow-induced vibration response to winds of different directions in the natural environment, and can collect fluid energy in all directions, thereby improving energy capture efficiency and increasing the utilization rate of wind energy; and the structure is simple, easy to assemble, small in size, and has strong environmental adaptability. It can partially replace the use of batteries, which is conducive to promoting the application of omnidirectional wind energy capture devices in the field of self-powered energy.

[0022] 2. The omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by the present invention features a spherical excitation device. Compared to cylindrical and square-prism excitation devices, the spherical excitation device, due to its unique geometric shape, can vibrate up and down under the influence of incoming flow from all directions, thereby achieving multi-directional wind energy collection. Furthermore, the spherical excitation device has a larger excitation amplitude, improving energy capture efficiency. Compared to existing wind direction collection devices, it can collect wind direction from a wider range and achieve higher collection efficiency.

[0023] 3. The present invention provides an omnidirectional wind energy capture device based on spherical vortex-induced vibration. The material of the spherical oscillating device is foam plastic. By reducing the mass of the oscillating device, the vibration frequency and displacement amplitude of the capture device are increased to improve the wind energy capture efficiency. When a certain speed of airflow passes through the spherical oscillating device, vortex shedding is alternately generated on the surface of the oscillating device, resulting in periodic alternating pressure on the oscillating device, and vortex-induced vibration occurs under the action of fluid-solid coupling. The vibration of the oscillating device will drive the deformation of the upper and lower springs, and then the deformation of the piezoelectric beam. The piezoelectric beam is subjected to periodic stress and outputs electrical energy. Due to the geometric symmetry of the sphere, when wind from all directions on the plane acts on the oscillating device, it will produce the same vibration response, which has the characteristics of multi-directional wind energy collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic structural diagram of an omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by an embodiment of the present invention;

[0025] Figure 2 A top view of a piezoelectric beam provided in an embodiment of the present invention;

[0026] Figure 3 A front view of an omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by an embodiment of the present invention;

[0027] Figure 4 A bottom view of an omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of horizontal wind exposure of an omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by an embodiment of the present invention;

[0029] Figure 6 A schematic diagram of the power generated by the omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by an embodiment of the present invention.

[0030] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0031] 1-fixed bracket, 2-piezoelectric beam, 3-steel frame, 4-upper spring, 5-lower spring, 6-sphere excitation device, 7-support. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0033] The embodiment of the present invention provides an omnidirectional wind energy capture device based on vortex-induced vibration of a sphere, such as Figure 1-4 As shown, it includes: a fixed bracket 1, a spherical oscillating device 6, a piezoelectric beam 2 and a support 7;

[0034] The spherical oscillating device is connected to the upper end of the fixed bracket and the piezoelectric beam through an upper spring 4 and a lower spring 5 respectively.

[0035] Specifically, the upper end of the fixing bracket is connected to the spherical oscillating device via an upper spring, and the piezoelectric beam is connected to the spherical oscillating device via a lower spring.

[0036] One side of the piezoelectric beam is provided with a sliding groove, which forms a linear guide mechanism with a fixing member (such as a bolt, a column, etc.) provided on the support, and the other side is fixedly connected to the support (for example, fastened by a bolt).

[0037] The principle of the present invention is: the wind energy capture device is placed in the required environment. When the airflow acts on the capture device, the oscillation device will generate self-excited vibration, causing the spring to deform, thereby driving the piezoelectric beam to undergo periodic bending deformation. The stress on the piezoelectric beam alternately increases and decreases. Due to the piezoelectric effect, the piezoelectric beam will generate an electric potential difference, thereby converting the vibration energy into electrical energy output.

[0038] like Figure 5 As shown, the arrow indicates the wind direction. When airflow at a certain speed passes through the spherical excitation device, vortex shedding alternately occurs on the surface of the device, generating periodic alternating pressure and, under the action of fluid-structure coupling, vortex-induced vibration. The vibration of the spherical excitation device drives the piezoelectric beam 2 to flexural vibration via the lower spring 5, subjecting it to periodic stress and, in turn, outputting electrical energy. Due to the geometric symmetry of the sphere, wind from all directions in the plane acting on the spherical excitation device produces the same vibration response, enabling multi-directional wind energy harvesting.

[0039] By setting up a linear guide mechanism, when the spherical oscillation device is affected by the wind flow and drives the upper and lower springs to vibrate up and down, compared with the method in which both sides of the piezoelectric beam are fixedly connected to the support, the piezoelectric beam can produce a larger bending deformation, thereby improving the wind energy collection rate of the device and having a wider applicable wind speed range.

[0040] Preferably, sliding grooves may be provided on both sides of the piezoelectric beam to form linear guide mechanisms with fixing members provided on the support.

[0041] The length of the sliding groove can be set according to actual needs, for example: 10mm.

[0042] The lower end of the support is fixedly connected to the lower end of the fixing bracket.

[0043] That is, the lower end of the fixed bracket is connected to the support, the support is provided with a piezoelectric beam, and the upper end of the piezoelectric beam is connected to the lower end of the lower spring.

[0044] Specifically, the support is used to provide space for the downward bending deformation of the piezoelectric beam, such as Figure 1 As shown, the support is annular and is fixedly connected to the lower end of the support via a support column, and the piezoelectric beam is arranged on the annular ring.

[0045] Preferably, the piezoelectric beam includes a beam II and a piezoelectric sheet I adhered to the beam.

[0046] Specifically, the piezoelectric sheet can be attached to the upper and lower sides or one side of the beam.

[0047] The material of the beam may be steel.

[0048] The piezoelectric sheet may be a piezoelectric sheet of model MFC-M2807-P2.

[0049] Preferably, the spherical oscillating device is made of foam plastic.

[0050] Specifically, the material of the spherical oscillating device is foam plastic; the spherical oscillating device can be hollow or solid.

[0051] The spherical oscillating device and the fixing bracket can both be processed by 3D printing.

[0052] Preferably, the upper and lower ends of the fixing bracket are connected by at least one supporting shaft.

[0053] Preferably, the upper and lower ends of the fixing bracket are connected by a plurality of evenly distributed support shafts.

[0054] Preferably, the support shaft is made of tungsten steel.

[0055] Preferably, the upper and lower ends of the fixing bracket and the support are made of nylon.

[0056] Preferably, the upper end of the fixing bracket is connected to the upper spring through the steel frame 3.

[0057] Specifically, the steel frame may be cross-shaped, M-shaped, etc., and the steel frame is fastened to the upper end of the fixed bracket by bolts.

[0058] like Figure 1 As shown, the upper and lower ends of the fixed bracket can be hollowed out. To facilitate the connection between the upper end of the upper spring and the upper end of the fixed bracket, a steel frame connected to the upper end of the fixed bracket provides a fulcrum for the connection between the upper end of the upper spring and the upper end of the fixed bracket, thereby improving the stability of the device. Specifically, a fixed steel beam is provided at the upper end of the fixed bracket, which is connected to the spherical excitation device through the upper spring. The axis connecting the upper and lower springs of the spherical excitation device is perpendicular to the surface of the piezoelectric beam and the cross-shaped steel beam, ensuring stable operation of the capture device.

[0059] In order to facilitate the installation of the wind energy capture device and extend the service life of the fixed bracket, Figure 1The upper and lower supports of the fixed bracket shown are made of nylon and connected by 220mm long, 1mm diameter tungsten steel rods. The rods are fastened to the upper and lower supports by rolled strips. The three tungsten steel rods are arranged 120° apart. The lower support of the fixed bracket is equipped with fixing holes to secure the piezoelectric beam, facilitating the installation of the piezoelectric beam and the cross-shaped steel beam. The upper end of the fixed bracket is equipped with a cross-shaped fixing steel beam to facilitate the installation of the upper spring. The support is equipped with a piezoelectric beam, which consists of a piezoelectric plate (MFC-M2807-P2) I bonded to a steel beam II. One side of the piezoelectric beam has a 10mm sliding groove, which cooperates with the bolts of the lower support of the fixed bracket to form a linear guide mechanism. The other side is connected to the lower support of the fixed bracket. The piezoelectric plate is 35mm long and 8mm wide, and the thickness is negligible. The steel beam is 140mm long, 10mm wide, and 0.6mm thick. The steel beam has strong elastic strain capacity, which is conducive to the oscillation effect of the structure. The cross-shaped steel beam is perforated with 3mm holes on all four sides to facilitate bolt connection to the upper support of the fixed bracket. The axes of the upper and lower springs are perpendicular to the top and bottom of the fixed bracket, ensuring stable operation of the wind energy capture device. The spherical excitation device is designed to vibrate in response to incoming flow from all directions, thus achieving multi-directional wind energy collection.

[0060] The piezoelectric transduction mechanism adopted in the present invention can also be replaced by electromagnetic and triboelectric transduction mechanisms.

[0061] like Figure 1 、 3 As shown, the spherical excitation device is fixedly connected to the top of the fixed bracket through a spring and a cross-shaped steel beam; the piezoelectric beam is connected to the spherical excitation device through a spring; the piezoelectric beam is fixed to the bottom of the fixed bracket; and the cross-shaped steel frame is fixed to the top of the fixed bracket.

[0062] The material of the spherical excitation device can be foam plastic, and the processing method of the spherical excitation device and the upper and lower ends of the fixed bracket 1 is 3D printing. The spherical excitation device is light in weight and has low rigidity. The airflow can more easily cause the spherical excitation device to oscillate, causing the piezoelectric beam 2 to output electrical energy.

[0063] The wind energy capture device is placed in the required environment. When the airflow acts on the capture device, the spherical oscillation device will generate self-excited vibration, and transmit the vibration to the piezoelectric beam 2 through the lower spring 5, so that the piezoelectric beam 2 undergoes periodic bending deformation. The stress on the piezoelectric beam 2 alternately increases and decreases. Due to the piezoelectric effect, the piezoelectric beam will generate an electric potential difference, thereby converting the vibration energy into electrical energy output. The wind energy capture device in this scheme can respond to winds of different directions in the natural environment and output higher electrical energy. It has a simple structure, is easy to assemble, and is small in size, which is conducive to promoting the application of wind energy capture devices in the field of self-powered energy.

[0064] The wind energy capture device provided by the embodiment of the present invention is placed in a wind tunnel. The wind speed is adjusted by controlling the rotation speed of the fan through a flow rate controller. The system wind speed is measured by a Pitot tube anemometer. The omnidirectional test is performed by adjusting the placement angle of the wind energy capture device. The voltage across the load resistor R is measured by an oscilloscope. The output power can be calculated by the formula Get, where V rms is the root mean square (RMS) voltage, which is given by the formula It is calculated, where T1 is the previous sampling time, T2 is the current sampling time, and V is the voltage generated by the piezoelectric piece at the current time; the amplitude of the spherical blunt body is captured by a 250FPS (Frames Per Second) camera, and then the image is processed by a computer to obtain the true amplitude of the sphere.

[0065] The test results are as follows Figure 6 As shown, where U is the wind speed, Figure 6 It can be seen that the omnidirectional wind energy capture device based on spherical vortex-induced vibration provided by the embodiment of the present invention has high output energy and a wide range of effective working wind speeds in all wind directions, achieving the goal of omnidirectional wind energy collection. The omnidirectional wind energy capture device of the present invention has good omnidirectionality and has similar average output power at all positions.

[0066] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An omnidirectional wind energy capture device based on spherical vortex-induced vibration, characterized in that: include: Fixed bracket, spherical oscillating device, piezoelectric beam and support; The spherical oscillating device is connected to the upper end of the fixed bracket and the piezoelectric beam through upper and lower springs respectively; One side of the piezoelectric beam is provided with a sliding groove, which forms a linear guide mechanism with a fixing member provided on the support, and the other side is fixedly connected to the support; The lower end of the support is fixedly connected to the lower end of the fixing bracket; By setting up a linear guide mechanism, when the spherical oscillation device is affected by the wind flow and drives the upper and lower springs to vibrate up and down, compared with the method in which both sides of the piezoelectric beam are fixedly connected to the support, the piezoelectric beam produces a greater bending deformation, thereby improving the wind energy collection rate of the device and having a wider applicable wind speed range.

2. An omnidirectional wind energy capture device based on spherical vortex-induced vibration, characterized in that: include: Fixed bracket, spherical oscillating device, piezoelectric beam and support; The spherical oscillating device is connected to the upper end of the fixed bracket and the piezoelectric beam through upper and lower springs respectively; Sliding grooves are provided on both sides of the piezoelectric beam, and they respectively form a linear guide mechanism with the fixing parts provided on the support; The lower end of the support is fixedly connected to the lower end of the fixing bracket; By setting up a linear guide mechanism, when the spherical oscillation device is affected by the wind flow and drives the upper and lower springs to vibrate up and down, compared with the method in which both sides of the piezoelectric beam are fixedly connected to the support, the piezoelectric beam produces a greater bending deformation, thereby improving the wind energy collection rate of the device and having a wider applicable wind speed range.

3. The device according to claim 1 or 2, characterized in that The piezoelectric beam comprises a beam and a piezoelectric sheet adhered to the surface of the beam.

4. The device according to claim 1 or 2, characterized in that The material of the spherical oscillating device is foam plastic.

5. The device according to claim 1 or 2, characterized in that The upper and lower ends of the fixing bracket are connected via at least one supporting shaft.

6. The device according to claim 1 or 2, characterized in that The upper and lower ends of the fixed bracket are connected via a plurality of evenly distributed support shafts.

7. The device according to claim 6, characterized in that The support shaft is made of tungsten steel.

8. The device according to claim 1 or 2, characterized in that The upper end of the fixing bracket is connected to the upper spring through an intermediate piece.

9. The device according to claim 1 or 2, characterized in that The upper and lower ends of the fixing bracket and the support are made of nylon.

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