Oscillating hydrofoil type optimization long-time self-sustaining energy collection device and energy collection method

Abstract

The invention discloses an oscillating hydrofoil type optimization long-time self-sustaining energy collection device and an energy collection method. The energy collecting device comprises a plurality of oscillating hydrofoil units which are arranged at intervals, and the oscillating hydrofoil units are distributed in an array mode. Each oscillating hydrofoil unit comprises a hydrofoil shell and a friction nano-generator, a plurality of friction nano-generators which are arranged in parallel along the chord length of the hydrofoil chord and cling to each other are arranged in the hydrofoil shell, and the size of each friction nano-generator changes along with the thickness of the hydrofoil shell; and the upper and lower cambered surfaces of each friction nano-generator are tangent to the inner wall of the hydrofoil shell. When the oscillating hydrofoil unit performs pitching or surging under the action of tidal current, the friction nano-generator in the oscillating hydrofoil unit captures mechanical energy in real time and generates power, a traditional oscillating hydrofoil energy conversion device is replaced, the structure is simpler, production is simpler and more convenient, cost is lower, and energy capturing efficiency and self-sustaining performance are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy collection, and in particular to an oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device and an energy collection method. Background Art

[0002] my country has a long and narrow coastline, numerous rivers and lakes, and considerable marine and hydropower resources. With the development of human society, human demand for energy is increasing, so a more comprehensive development of marine resources is an inevitable trend. Tidal energy has the advantages of high energy density and wide distribution. It is a renewable clean energy that is most easily used directly and inexhaustible. Therefore, self-sustaining and long-term working wave energy collection devices have become a hot topic of research.

[0003] With the development of tidal energy technology in my country in recent years, many tidal energy units in my country have been successfully connected to the grid or supply electricity to islands. However, most tidal energy devices in my country are horizontal axis type, with poor starting performance, not suitable for shallow waters, and insufficient development of tidal resources; generally, under the same sea depth, the swept area of ​​the oscillating hydrofoil is about 3 times the swept area of ​​the horizontal axis impeller. The oscillating hydrofoil technology for capturing tidal energy for power generation has obvious advantages in shallow waters and is particularly suitable for installation in shallow waters such as riverbeds and coastal areas. Summary of the invention

[0004] Based on the poor starting performance of current tidal energy devices and the low capture efficiency in shallow offshore waters, in order to develop and utilize the vast and abundant shallow sea tidal energy resources, the present invention provides an oscillating hydrofoil airfoil optimized long-time self-sustaining energy collection device and an energy collection method, which can capture tidal energy under the action of waves in shallow water or riverbed areas and convert it into electrical energy, and can work automatically for a long time.

[0005] The technical solution adopted by the present invention is:

[0006] 1. An oscillating hydrofoil airfoil optimized long-term self-sustaining energy harvesting device

[0007] It comprises a plurality of oscillating hydrofoil units arranged at intervals, and the plurality of oscillating hydrofoil units are distributed in an array; each of the oscillating hydrofoil units comprises a hydrofoil shell and a friction nanogenerator, and the hydrofoil shell is provided with a plurality of friction nanogenerators arranged in parallel along the chord length, and the upper and lower arc surfaces of each of the friction nanogenerators are tangent to the inner wall of the hydrofoil shell.

[0008] The hydrofoil shell is a NACA series airfoil shape, and the hydrofoil shell has an upper surface and a lower surface, both of which are convex curved surfaces, the side of the hydrofoil shell that first contacts the tide is used as the leading edge, and the side of the hydrofoil shell that last contacts the tide is used as the trailing edge; the curvature of the upper surface is greater than the curvature of the lower surface and the maximum curvature is 15%-25% of the chord length, the radius of the inscribed circle of the leading edge is 1%-3% of the chord length, the maximum thickness of the hydrofoil shell is 12%-18% of the chord length, the maximum thickness position of the hydrofoil shell is 30%-40% of the chord length close to the leading edge, and at the trailing edge of the hydrofoil shell, the upper surface and the lower surface are connected by a progressive change for passivation transition.

[0009] The friction nanogenerator includes multiple friction nanogenerator units, a lithium battery and a shell. The shell is a cylindrical hollow shell. Multiple friction nanogenerator units and lithium batteries are encapsulated in the shell. Each of the friction nanogenerator units is electrically connected to the lithium battery. The arc portion of the outer surface of each friction nanogenerator unit fits tightly with the curved inner wall of the shell. The friction nanogenerator units are stacked from top to bottom in ascending order, and each of the friction nanogenerator units is fixedly connected to the shell.

[0010] The friction nano power generation unit comprises a power generation substrate and a group of cross rollers, wherein the power generation substrate is provided with an arc-shaped groove body, and a group of cross rollers are placed on the arc-shaped inner wall of the arc groove body of the power generation substrate along the groove length, wherein the group of cross rollers comprises at least two rollers with different electronegativity materials attached to the surface;

[0011] The power generation substrates with the cross rollers are stacked up and down so that the side profile of the stacked power generation substrates is circular, and the arcuate groove of the power generation substrate arranged at the bottom is smaller than the arcuate groove of the power generation substrate arranged at the top.

[0012] The power generation substrate is mainly composed of a top layer, interdigital electrodes and a bottom layer which are stacked in sequence from top to bottom and are tightly stacked. An interdigital electrode is arranged between the top layer and the bottom layer. The top layer is a nylon layer, and the bottom layer is a polylactic acid layer.

[0013] The cross rollers include a plurality of rollers I and a plurality of rollers II, and the rollers I and II are alternately and closely arranged along the groove length on the arc-shaped inner wall of the arc groove body of the power generation substrate. The rollers I and II are both cylinders, and polytetrafluoroethylene is attached to the surface of the roller I, and nylon is attached to the surface of the roller II.

[0014] Each power generation substrate of the friction nano power generation unit is electrically connected to the lithium battery via a diode bridge.

[0015] An anchor chain mooring is respectively arranged at the lower part of the four corners of the hydrofoil shell, and the anchor chain mooring is a non-stop anchor chain type. Each oscillating hydrofoil unit is connected to the seabed or riverbed by an anchor chain mooring.

[0016] A plurality of the oscillating hydrofoil units are arranged horizontally in a row as a group of horizontal rows, and multiple groups of horizontal rows are longitudinally arranged in parallel on the same horizontal plane to form an array. The lateral spacing between each oscillating hydrofoil unit is 4-6 times the chord length of the wing, and the spacing between each group of horizontal rows is 0.25-0.3 times the chord length of the wing.

[0017] 2. An energy harvesting method based on the optimization of the long-term self-sustaining energy harvesting device based on the oscillating hydrofoil airfoil

[0018] The method comprises the following steps:

[0019] 1) Multiple oscillating hydrofoil units are fixed to the seabed or riverbed through anchor chains to form an array distribution on the water surface;

[0020] 2) When the tidal current acts, the tidal current causes each oscillating hydrofoil unit to pitch or swing on the water surface, and the cross rollers in the friction nanogenerator in each oscillating hydrofoil unit roll on the power generation substrate. The surfaces of rollers I and II rub against each other, thereby generating surface charges. The surface of roller I generates positive charges, and the surface of roller II generates negative charges. The surface charges are induced by the top layer and the interdigital electrodes of the power generation substrate through the electrostatic induction effect, so that the top layer generates positive charges and the interdigital electrodes generate negative charges. Combined with the reciprocating changes in the relative positions of the top layer and the interdigital electrodes and the cross rollers, the electrons are driven to move back and forth in the circuit, thereby forming an alternating current signal;

[0021] 3) The AC signal described in step 2 is converted into a DC signal by a diode bridge and then transferred to the lithium battery to charge the lithium battery.

[0022] The beneficial effects of the present invention are:

[0023] 1. The friction nanogenerator is used to convert the tidal energy captured by the oscillating hydrofoil turbine, replacing the previous complex energy conversion device, which is easier to produce, lower cost and simpler in structure.

[0024] 2. The traditional hydrofoil structure has been optimized and the energy capture efficiency of the hydrofoil has been improved.

[0025] 3. The oscillating hydrofoil unit is fixed by anchor chains, which can improve the self-sustainability of the energy capture device, reduce maintenance times and reduce costs.

[0026] 4. Each oscillating hydrofoil unit is distributed in an array to enhance the positive influence between the oscillating hydrofoil units, which can enhance each other's energy capture efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the overall design diagram of the oscillating hydrofoil unit.

[0028] Figure 2 This is the overall design diagram of the friction nanogenerator.

[0029] Figure 3 This is the front view of the friction nanogenerator.

[0030] Figure 4 Schematic diagram of the decomposition of the friction nanogenerator.

[0031] Figure 5 This is the power generation principle diagram of the friction nanogenerator.

[0032] Figure 6 Schematic diagram of the distribution of oscillating hydrofoil unit array.

[0033] In the figure: 1. hydrofoil shell, 2. friction nanogenerator, 3. anchor chain mooring, 4. shell, 5. cross rollers, 6. power generation substrate, 7. roller I, 8. roller II, 9. interdigitated electrodes, 10. top layer, 11. bottom layer, 12. lithium battery, 13. diode bridge. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The present invention comprises a plurality of oscillating hydrofoil units arranged at intervals, and the plurality of oscillating hydrofoil units are distributed in an array; the overall design diagram of the oscillating hydrofoil unit is as follows: Figure 1 As shown, each oscillating hydrofoil unit includes a hydrofoil shell 1 and a friction nanogenerator 2. A plurality of friction nanogenerators 2 arranged in parallel along the chord length are arranged in the hydrofoil shell 1. The size of each friction nanogenerator 2 varies with the thickness of the hydrofoil shell 1, so that the upper and lower arc surfaces of each friction nanogenerator 2 are tangent to the inner wall of the hydrofoil shell 1.

[0036] The hydrofoil shell 1 is a NACA series airfoil, that is, a cylinder with a shuttle-shaped cross-section. The hydrofoil shell 1 has an upper surface and a lower surface, both of which are convex curved surfaces. The side of the hydrofoil shell (1) that first contacts the tide is the leading edge, and the side of the hydrofoil shell (1) that last contacts the tide is the trailing edge; wherein the curvature of the upper surface is greater than the curvature of the lower surface and the maximum curvature is 15%-25% of the chord length of the wing. The curvature of the airfoil affects the separation point and reattachment point of the fluid, and can obtain more lift at low speeds. A larger curvature usually causes the fluid to generate a greater acceleration on the airfoil surface, thereby increasing the lift. The radius of the inscribed circle of the leading edge is 1%-3% of the chord length of the wing. A smaller radius helps to enhance the leading edge vortex, increase the lift, and help to maintain flow attachment. The maximum thickness of the hydrofoil shell 1 is 12%-18% of the chord length of the wing. A larger thickness increases the structural strength and lift. However, it will relatively increase the resistance. At low speeds, the greater thickness will increase the lift. The thicker airfoil helps to delay separation and maintain the attached flow. The maximum thickness of the hydrofoil shell 1 is located at 30%-40% of the chord length close to the leading edge. The maximum thickness closer to the front can increase the lift performance. At the trailing edge of the hydrofoil shell 1, the upper surface and the lower surface are connected by a progressive change for a blunt transition. Compared with the NACA series airfoils, the trailing edge of the hydrofoil shell 1 is blunter or smoother to reduce the degree of water flow separation and allow the water flow to smoothly leave the wing surface. The smooth trailing edge can reduce the generation of turbulence and reduce the intensity of the vortex, thereby reducing resistance and increasing lift. The blunt trailing edge helps to delay separation and reduce instability. The progressive change allows the water flow to gradually adapt to the shape of the trailing edge, making the water flow more stable when leaving the wing surface, thereby reducing vortex losses and improving energy capture efficiency.

[0037] The overall design of the friction nanogenerator is shown in the figure below. Figure 2 As shown, the front view is as Figure 3 As shown, the friction nanogenerator 2 includes multiple friction nanogenerator units, a lithium battery 12 and a shell 4. The shell 4 is a cylindrical hollow shell and is made of polymethyl methacrylate. Multiple friction nanogenerator units and lithium batteries 12 are encapsulated in the shell 4. Each friction nanogenerator unit is electrically connected to the lithium battery 12. The arc portion of the outer surface of each friction nanogenerator unit is tightly fitted with the curved inner wall of the shell 4. The friction nanogenerator units are stacked from top to bottom in an ascending order, and each friction nanogenerator unit is fixedly connected to the shell 4.

[0038] The friction nano power generation unit is a cross roller structure, including a power generation substrate 6 and a group of cross rollers 5. The power generation substrate 6 is provided with an arc-shaped groove. A group of cross rollers 5 are placed along the length of the groove on the arc-shaped inner wall of the arc groove of the power generation substrate 6, and can roll on the power generation substrate 6. A group of cross rollers 5 includes at least two rollers with different electronegativity materials attached to the surface. The schematic diagram of the decomposition of the friction nano generator is shown in FIG. Figure 4As shown, the power generation substrates 6 on which the cross rollers 5 are placed are stacked up and down, so that the side profile of the stacked power generation substrates 6 is circular, and the arcuate groove of the power generation substrate 6 arranged at the bottom is smaller than the arcuate groove of the power generation substrate 6 arranged at the top.

[0039] More specifically, the power generation substrate 6 is mainly composed of a top layer 10, interdigitated electrodes 9 and a bottom layer 11 which are stacked tightly from top to bottom, with the interdigitated electrodes 9 arranged between the top layer 10 and the bottom layer 11. The top layer 10 is a thin layer of nylon, and the bottom layer 11 is a thin layer of polylactic acid. The thickness of the top layer 10, the interdigitated electrodes 9 and the bottom layer 11 are all 10 to 15 mm.

[0040] The cross roller 5 includes a plurality of rollers I7 and a plurality of rollers II8. The rollers I7 and II8 are alternately and closely arranged along the groove length on the arc-shaped inner wall of the arc groove body of the power generation substrate 6. The rollers I7 and II8 are both cylinders with a diameter of 30 mm and are made of acrylic material. A polytetrafluoroethylene film with a thickness of 60 μm is attached to the surface of the roller I7, and a nylon film with a thickness of 60 μm is attached to the surface of the roller II8. The material of the forked electrode 9 is copper and is cut from copper. To avoid charge cancellation, the width of the forked electrode 9 is 30 mm.

[0041] Each power generation substrate 6 of the friction nano power generation unit is electrically connected to the lithium battery 12 via a diode bridge 13 , and the diode bridge 13 converts the AC signal generated by the power generation substrate 6 into a DC signal.

[0042] An anchor chain mooring 3 is provided at the lower part of each of the four corners of the hydrofoil shell 1. The anchor chain mooring 3 is a non-stop anchor chain type and is made of anchor chain steel. Each oscillating hydrofoil unit is connected to the seabed or riverbed by an anchor chain through the anchor chain mooring 3.

[0043] The schematic diagram of the oscillating hydrofoil unit array distribution is as follows: Figure 6 As shown, several oscillating hydrofoil units are arranged horizontally in a row as a group of horizontal rows, and multiple groups of horizontal rows are distributed vertically in parallel on the same horizontal plane to form an array, which can enhance the energy capture efficiency of each oscillating hydrofoil unit. The lateral spacing between each oscillating hydrofoil unit is 4-6 times the chord length of the wing, so as to avoid the influence of the trailing edge vortex of the oscillating hydrofoil unit distributed in the front on the energy capture efficiency of the oscillating hydrofoil unit distributed in the rear during the oscillation process as much as possible. The spacing between each group of horizontal rows is 0.25-0.3 times the chord length of the wing, so as to enhance the energy capture efficiency of the oscillating hydrofoil unit by the wing surface effect as much as possible.

[0044] Based on the above-mentioned oscillating hydrofoil airfoil optimization, a method for energy collection of a long-term self-sustaining energy collection device is provided. The power generation principle diagram of the friction nanogenerator is shown in FIG. Figure 5 As shown, the method comprises the following steps:

[0045] 1) In the sea or river, multiple oscillating hydrofoil units are fixed to the seabed or riverbed through anchor chain mooring 3 to form an array distribution on the water surface; specifically, they are preferably arranged under the water surface and near the water surface.

[0046] 2) When the tidal current acts, the tidal current causes each oscillating hydrofoil unit to pitch or swing on the water surface, and the cross rollers 5 in the friction nanogenerators 2 in each oscillating hydrofoil unit roll on the power generation substrate 6. The surfaces of rollers I7 and II8 rub against each other, thereby generating surface charges. More specifically, the surface of roller I7 generates positive charges, and the surface of roller II8 generates negative charges. The surface charges are induced by the top layer 10 and the interdigital electrodes 9 of the power generation substrate 6 through the electrostatic induction effect, so that the top layer 10 generates positive charges, and the interdigital electrodes 9 generate negative charges. Combined with the reciprocating changes in the relative positions of the top layer 10 and the interdigital electrodes 9 and the cross rollers 5, the electrons are driven to move back and forth in the circuit, thereby forming an alternating current signal, thereby realizing the process of capturing mechanical energy and converting it into electrical energy;

[0047] 3) The AC signal is converted into a DC signal by the diode bridge 13 and then transferred to the lithium battery 12 to charge the lithium battery 12, and the converted electrical energy is collected and stored.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the method of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device, characterized in that: The invention comprises a plurality of oscillating hydrofoil units arranged at intervals, wherein the plurality of oscillating hydrofoil units are distributed in an array; each of the oscillating hydrofoil units comprises a hydrofoil shell (1) and a friction nanogenerator (2); a plurality of friction nanogenerators (2) arranged in parallel along the chord length are arranged in the hydrofoil shell (1); and the upper and lower arc surfaces of each of the friction nanogenerators (2) are tangent to the inner wall of the hydrofoil shell (1).

2. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claim 1, characterized in that: The hydrofoil shell (1) is a NACA series airfoil, and has an upper surface and a lower surface, both of which are convex curved surfaces, and the side of the hydrofoil shell (1) that first contacts the tidal current is the leading edge, and the side of the hydrofoil shell (1) that last contacts the tidal current is the trailing edge; The curvature of the upper surface is greater than that of the lower surface and the maximum curvature is 15%-25% of the chord length. The radius of the inscribed circle of the leading edge is 1%-3% of the chord length. The maximum thickness of the hydrofoil shell (1) is 12%-18% of the chord length. The maximum thickness position of the hydrofoil shell (1) is 30%-40% of the chord length near the leading edge. At the trailing edge of the hydrofoil shell (1), the upper surface and the lower surface are connected by a progressive transition.

3. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy harvesting device according to claim 1, characterized in that: The friction nanogenerator (2) comprises a plurality of friction nanogenerator units, a lithium battery (12) and a shell (4); the shell (4) is a cylindrical hollow shell; the shell (4) encapsulates a plurality of friction nanogenerator units and a lithium battery (12); each of the friction nanogenerator units is electrically connected to the lithium battery (12); the arc portion of the outer surface of each of the friction nanogenerator units is tightly fitted with the curved inner wall of the shell (4); the friction nanogenerator units are stacked from top to bottom in an ascending order; and each of the friction nanogenerator units is fixedly connected to the shell (4).

4. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claim 3, characterized in that: The friction nano power generation unit comprises a power generation substrate (6) and a group of cross rollers (5), the power generation substrate (6) is provided with an arc-shaped groove body, a group of cross rollers (5) are placed on the arc-shaped inner wall of the arc groove body of the power generation substrate (6) along the groove length, and the group of cross rollers (5) comprises at least two rollers with different electronegativity materials attached to the surface; The power generation substrates (6) on which the cross rollers (5) are placed are stacked up and down, so that the side profile of the stacked power generation substrates (6) is circular, and the arcuate trough of the power generation substrate (6) arranged at the bottom is smaller than the arcuate trough of the power generation substrate (6) arranged at the top.

5. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claim 4, characterized in that: The power generation substrate (6) is mainly composed of a top layer (10), a forked electrode (9) and a bottom layer (11) which are stacked in sequence from top to bottom and are tightly stacked, wherein the forked electrode (9) is arranged between the top layer (10) and the bottom layer (11), the top layer (10) is a nylon layer, and the bottom layer (11) is a polylactic acid layer.

6. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claim 4, characterized in that: The cross roller (5) includes a plurality of rollers I (7) and a plurality of rollers II (8), wherein the rollers I (7) and rollers II (8) are alternately and closely arranged along the groove length on the arc-shaped inner wall of the arc groove body of the power generation substrate (6), and the rollers I (7) and rollers II (8) are both cylinders, and polytetrafluoroethylene is attached to the surface of the roller I (7), and nylon is attached to the surface of the roller II (8).

7. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claim 4, characterized in that: Each power generation substrate (6) of the friction nano power generation unit is electrically connected to the lithium battery (12) via a diode bridge (13).

8. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claim 1, characterized in that: An anchor chain mooring (3) is provided at the lower part of each of the four corners of the hydrofoil shell (1), and the anchor chain mooring (3) is a non-stop anchor chain type, and each oscillating hydrofoil unit is connected to the seabed or riverbed by an anchor chain through the anchor chain mooring (3).

9. The oscillating hydrofoil airfoil optimized long-term self-sustaining energy harvesting device according to claim 1, characterized in that: A plurality of the oscillating hydrofoil units are arranged horizontally in a row as a group of horizontal rows, and multiple groups of horizontal rows are longitudinally arranged in parallel on the same horizontal plane to form an array. The lateral spacing between each oscillating hydrofoil unit is 4-6 times the chord length of the wing, and the spacing between each group of horizontal rows is 0.25-0.3 times the chord length of the wing.

10. An energy collection method based on the oscillating hydrofoil airfoil optimized long-term self-sustaining energy collection device according to claims 1-9, characterized in that: The method comprises the following steps: 1) fixing a plurality of oscillating hydrofoil units to the seabed or riverbed through anchor chain mooring (3) to form an array distribution on the water surface; 2) When the tidal current acts, the tidal current causes each oscillating hydrofoil unit to pitch or swing on the water surface, and the cross rollers (5) in the friction nanogenerators (2) in each oscillating hydrofoil unit roll on the power generation substrate (6). The surfaces of rollers I (7) and rollers II (8) rub against each other, thereby generating surface charges. The surface of rollers I (7) generates positive charges, and the surface of rollers II (8) generates negative charges. The surface charges are induced by the top layer (10) and the interdigital electrodes (9) of the power generation substrate (6) through the electrostatic induction effect, so that the top layer (10) generates positive charges, and the interdigital electrodes (9) generate negative charges. Combined with the reciprocating changes in the relative positions of the top layer (10) and the interdigital electrodes (9) and the cross rollers (5), the electrons are driven to move back and forth in the circuit, thereby forming an alternating current signal; 3) The alternating current signal described in step 2 is converted into a direct current signal by the diode bridge (13) and then transferred to the lithium battery (12) to charge the lithium battery (12).

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