A narrow-slit wave-gathering type high-efficiency wave energy absorption device

Abstract

The present invention belongs to the field of marine energy utilization, and in particular, relates to a narrow-slit wave-gathering type high-efficiency wave energy absorption device, which is used for converting low-grade wave energy with a small wave height. The main structure includes a vertical wall, a wave-gathering float, an oscillating float, a pull rope, a pulley, a positioning rod, a support structure and a power generation equipment. Two groups of vertical walls form a contraction wave channel, and the contraction end of the wave channel is connected to the front end of the narrow-slit wave-gathering float for gathering wave energy. There is a narrow rectangular narrow slit in the middle of the wave-gathering float along the wave propagation direction, and the wave energy in the narrow slit is further enhanced through the narrow slit resonance principle. The oscillating float that swings vertically in the narrow slit generates electricity by dragging the power generation equipment through the pull rope. The present invention has a novel principle, a simple structure, a low construction cost, and a wide range of adaptability. It can effectively improve the economy and efficiency of wave energy conversion, and realize the full, economical and efficient utilization of low-grade renewable energy with low resource utilization value.

Description

Technical Field

[0001] The invention belongs to the technical field of ocean energy utilization and renewable energy power generation, and in particular relates to a narrow-slit wave-focusing type high-efficiency wave energy absorbing device. Background Art

[0002] Wave energy is a very promising clean and renewable energy source with the advantages of good energy quality, large storage capacity and wide distribution. Its development and utilization is of great significance to promoting sustainable development and the development of marine resources. In China, the development and utilization of wave energy has been included in the national energy development strategy and has broad development prospects.

[0003] Existing offshore wave energy utilization technologies can be divided into two categories: point absorption and line absorption. Point absorption wave energy conversion devices mainly use the displacement or relative displacement change generated by the heaving motion of the floating body in the waves, and convert the mechanical energy of the floating body movement into hydraulic energy or electromagnetic energy through PTO (Power Take-off) damping, and then pass through energy storage and transmission units such as accumulators to finally drive the generator to generate electricity, or produce fresh water or ice through other equipment. This type of device mainly includes specific types such as oscillating float type and oscillating water column type. Line absorption wave energy conversion devices can absorb wave energy at a certain distance along the wave propagation line, such as the famous British "Pelamis" type device. The device consists of multiple groups of articulated rafts. The rafts move under the excitation of waves, and the (angular) displacement between adjacent rafts changes. The mechanical energy of the raft movement is extracted through the PTO damping mechanism installed between adjacent rafts. In addition, the wave-riding device that reasonably utilizes the coastal terrain, converts the kinetic energy of the waves into potential energy, and then generates electricity using the sea water head pressure difference is also an important type.

[0004] The above-mentioned wave energy conversion device has a good energy conversion effect, but generally a good wave energy conversion effect can be obtained only when the wave height is relatively large; compared with the wave conditions in Europe, North America and other sea areas (wave height is 2.0m-6.0m), the wave height in most of the coastal waters of China is relatively small (0.5m-3.0m), and the wave energy flux density is relatively low, making it difficult to directly utilize the existing wave energy conversion devices with high efficiency, and the comprehensive utilization cost is relatively high, and even causing some scattered and low-grade wave energy resources to be wasted.

[0005] According to the hydrodynamic response theory of fluid in narrow gaps, when the wave incident frequency is close to the natural frequency of the water body confined in the narrow gap between the floating bodies, the water body in the narrow gap will produce hydrodynamic resonance. This resonance phenomenon will make the wave height in the narrow gap reach several times the incident wave height. By adopting this method, waves with small wave height and low energy flow density can be effectively gathered, thereby solving the problem of wave height being too small and utilizing wave energy more economically, fully and efficiently. Summary of the invention

[0006] The main purpose of the present invention is to provide a narrow-slit wave-focusing high-efficiency wave energy absorption device. The system has a simple structure and can improve the efficiency of wave energy utilization, so as to solve the problem that existing wave energy conversion devices are difficult to efficiently utilize low-grade wave energy resources with small wave heights.

[0007] The specific technical solution adopted by the present invention is as follows:

[0008] A narrow-slot wave-gathering high-efficiency wave energy absorption device is used for the efficient absorption and utilization of dispersed, low-grade wave energy with small wave height. The system is an independent offshore power generation unit, and its main structure includes vertical walls, wave-gathering buoys, oscillating buoys, pull ropes, pulleys, positioning rods, supporting structures, anchor systems and power generation equipment.

[0009] According to the conditions of the incident waves, the angle of the vertical wall that constitutes the contraction wave channel is adjusted so that the wave height of the incident wave increases after passing through the contraction wave channel, and the wave energy is gathered. The wave with increased wave height enters the wave gathering float and produces hydrodynamic interaction with the water body in the narrow gap. The wave height of the water body in the narrow gap increases, and the wave energy is further gathered. In particular, when the natural oscillation frequency of the water body in the narrow gap is close to the frequency of the wave entering the float, the water body in the narrow gap resonates, the wave height increases significantly, and the wave energy is gathered to the maximum extent. The oscillating float performs periodic heaving motion under the excitation of the waves in the narrow gap, converting the wave energy into the mechanical energy of the heaving motion of the oscillating float. The pull rope connected to the oscillating float drags the reel of the power generation equipment to rotate through two sets of pulleys above and below the water, driving the permanent magnet poles coaxial with the reel to rotate around the stator coil to achieve power generation. Among them, the positioning rods connected to the upper and lower parts of the oscillating float pass through the positioning holes on the supporting structure to ensure that the oscillating float always performs heaving motion relative to the narrow gap.

[0010] The two groups of symmetrically arranged vertical walls form a contraction wave channel, the contraction end is connected to the wave-gathering floating body through a hinge, and the angle between the vertical wall and the wave propagation direction changes within the range of 30° to 60°.

[0011] The wave-gathering floating body is an integral structure with a certain mass and volume floating on a certain depth of the wave surface, and forms a narrow slot resonance system with the narrow slot located in the middle, and provides support for the entire system.

[0012] The length and width of the oscillating float are slightly smaller than the corresponding dimensions of the narrow gap, and the thickness and draft of the oscillating float are consistent with those of the wave-gathering float.

[0013] One end of the four groups of positioning rods is connected to the oscillating float as a whole, and the other end of the positioning rod passes through the positioning hole arranged on the supporting structure and slides freely in the positioning hole.

[0014] The four groups of return springs are respectively sleeved on the four groups of positioning rods, and the two ends of the return springs are respectively fixed on the positioning holes and the positioning rods.

[0015] The pull rope has a certain elasticity and a large elastic coefficient. When the pull rope is in a taut state, it can effectively drag the reel of the power generation equipment to rotate.

[0016] The power generation equipment is installed on the wave-gathering floating body and has necessary insulation and waterproof properties.

[0017] The system of the present invention also includes four groups of anchoring systems, the anchor cables of which respectively connect the four end corners of the wave-gathering buoy to the seabed, so as to fix the entire system at a designated sea surface position and significantly reduce the movement amplitude of the wave-gathering buoy under wave excitation.

[0018] The present invention proposes a narrow-slot wave-gathering type high-efficiency wave energy absorption device. The system is based on the principle of narrow-slot fluid resonance between floating bodies. The system gathers waves by shrinking the wave channel. The narrow-slot fluid resonance absorbs and utilizes low-grade wave energy with small wave height and low utilization value. Compared with the prior art, the present invention has the advantages of novel principle, simple structure, low construction cost and wide application range, and is particularly suitable for the vast sea areas along the coast of China.

[0019] Beneficial effects of the present invention: The present invention improves the economy and efficiency of wave energy conversion, and realizes full, economical and efficient utilization of low-grade renewable energy with low resource utilization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 , Figure 2 It is a structural schematic diagram of the present invention, Figure 3 It is a structural diagram of a power generation device.

[0021] In the figure, 1, 2: vertical wall, 3, 4: wave-gathering float, 5: narrow gap, 6: oscillating float, 7, 8: supporting structure, 9, 10: positioning rod, 11, 12: positioning hole, 13, 14: return spring, 15, 16: pulley, 17: pull rope, 18: power generation equipment, 19, 20: hinge, 21, 22, 23, 24: anchoring, 25: incident wave, 18-1: stator coil, 18-2: permanent magnet pole, 18-3: reel, 18-4: rope guide. DETAILED DESCRIPTION

[0022] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the protection scope of the present invention.

[0023] Example: Figure 1 , Figure 2As shown, a narrow-slot wave-gathering type high-efficiency wave energy absorbing device, the main structure of which includes vertical walls 1, 2, wave-gathering floats 3, 4, a narrow slot 5, an oscillating float 6, a supporting structure 7, 8, positioning rods 9, 10, positioning holes 11, 12, return springs 13, 14, pulleys 15, 16, a pull rope 17, a power generation device 18, hinges 19, 20 and anchor systems 21, 22, 23, 24, etc.

[0024] The specific working process of the system includes secondary wave focusing and secondary energy conversion. First, the incident wave 18 enters the entrance of the contraction wave channel composed of symmetrically arranged vertical walls 1 and 2. As the wave channel contracts, the waves gather, the wave height increases, and the wave energy density increases, which is the first stage of wave focusing. Subsequently, the waves after the first stage of wave focusing pass through the front part 3 of the wave focusing float and the rear part 4 of the wave focusing float in turn, and produce hydrodynamic interactions with the water body in the narrow gap 5. The wave height in the narrow gap 5 increases significantly, and the wave energy density is further improved, which is the second stage of wave focusing. Under the excitation of the waves in the narrow gap 5 water body, the oscillating float 6 performs periodic heaving motion, converting the wave energy into the mechanical energy of the heaving motion of the oscillating float 6, which is the first stage of energy conversion. Among them, the positioning rods 11 and 12 connected to the upper and lower parts of the oscillating float 6 pass through the positioning holes 11 and 12 on the supporting structures 7 and 8 respectively to ensure that the oscillating float 6 always performs heaving motion relative to the wave focusing floats 3 and 4 in the narrow gap 5. The pull rope 17 connected to the oscillating float 6 drags the reel 18-3 of the power generation equipment 18 to rotate through two sets of pulleys 15 and 16 above and below the water. The permanent magnet pole 18-2 coaxial with the reel 18-3 rotates relative to the stator coil 18-1, cutting the magnetic lines of force to generate electricity, and finally converting the mechanical energy of the vertical swinging motion of the oscillating float 6 into electrical energy, which is the second level of energy conversion.

[0025] In this embodiment, the two groups of vertical walls 1 and 2 are symmetrically arranged to form a contraction channel structure, the wave inlet width of the wave channel is greater than the outlet width, and the wave outlet width is consistent with the crest line width of the front part 3 of the wave gathering floating body. The vertical walls 1 and 2 are connected to the two end corners of the front part 2 of the wave gathering floating body through hinges 19 and 20 respectively, so that the angle between the vertical walls 1 and 2 and the wave propagation direction can be changed in the range of 30° to 60° to obtain a better wave energy density.

[0026] The contraction channel structure composed of the two groups of vertical walls 1 and 2 described in this embodiment was subjected to specific wave focusing effect tests under different conditions. It was found that when the angle between the vertical walls 1 and 2 and the propagation direction of the incident wave 25 is 60°, the wave energy loss caused by wave reflection is the least and the wave focusing effect is the best. Specifically, assuming that the wave height of the wave is h at this time, and assuming that the wave entrance width of the contraction channel is 5.0b and the exit width is b, after the waves are gathered, the wave height obtained at the exit is about 2.1h, and the wave energy density is increased to 4.4 times the original value. At the same time, according to multiple actual test results, when the angle is in the range of 30° to 60°, the larger the wave entrance width of the contraction channel, the more significant the wave energy focusing effect.

[0027] The wave-gathering floats 3 and 4 have a certain volume and mass, float at a certain depth on the wave surface, and are divided into two identical wave-gathering float front part 3 and wave-gathering float rear part 4. There is a narrow rectangular slit 5 in the middle of the wave-gathering floats 3 and 4 along the wave propagation direction.

[0028] In this embodiment, it is found through numerical simulation that the immersion depth d of the wave-gathering buoys 3 and 4 is between 1 / 2 of the wave height H and 1 / 8 of the wavelength λ, and the smaller the wave circular frequency ω, the larger the immersion depth d should be set to ensure that the incident wave 25 can produce a stronger hydrodynamic effect on the water body in the narrow gap 5.

[0029] Furthermore, according to the conclusions of numerical simulation, within the main wave circular frequency range of China's coastal waters (1.05rsd / s≤ω≤3.14rad / s), the ratio s / L of the width s of the narrow slot 5 perpendicular to the wave crest line to the total width L of the wave-aggregating buoys 3 and 4 perpendicular to the wave crest line, and the relationship between the wave circular frequency ω when resonance is reached approximately conforms to the following linear relationship: s / L=-0.016ω+0.087, that is, s / L satisfies: 0.037≤s / L≤0.070, which can ensure that the water body in the narrow slot 5 can reach resonance under the wave conditions in China's coastal waters.

[0030] The oscillating float 6 is a rectangular parallelepiped float, the length and width of which are slightly smaller than the corresponding dimensions of the narrow slot 5 , and the thickness and draft are consistent with those of the wave-gathering floats 3 and 4 .

[0031] The two ends of the pull rope 17 are respectively connected to the center of the upper and lower surfaces of the oscillating float 6, and pass through the pulleys 15 and 16 connected to the supporting structures 7 and 8 in turn. The pull rope 17 has a certain elastic self-tightness and a large elastic coefficient. The pull rope 17 is always in a taut state and can effectively drag the reel 18-3 of the power generation equipment 18 to rotate.

[0032] There are four groups of positioning rods 9 and 10, one end of two groups of positioning rods 9 and 10 are connected to the upper and lower surfaces of the oscillating float 6 to form an integral structure, and the other ends of the positioning rods 9 and 10 pass through the positioning holes 11 and 12 on the supporting structures 7 and 8 respectively. The positioning rods 9 and 10 can slide freely in the positioning holes 11 and 12 to ensure that the oscillating float 6 only performs a single-degree-of-freedom vertical swing motion in the narrow gap 5.

[0033] There are two groups of support structures 7 and 8, which are fixedly mounted on the upper and lower surfaces of the rear portion 4 of the wave-gathering buoy, respectively. The crest line width of the support structures 7 and 8 is very narrow to reduce the impact on the propagation of the incident wave 25.

[0034] There are four groups of return springs 13 and 14, which are sleeved on the corresponding positioning rods 9 and 10, and the two ends of the return springs 13 and 14 are respectively fixed on the positioning holes 11 and 12 and the positioning rods 9 and 10. The return springs 13 and 14 provide part of the restoring force for the heaving motion of the oscillating float 6. Further, under static water conditions, the return springs 13 and 14 are in a naturally extended state.

[0035] The power generation equipment 18 is installed on the front part 3 of the wave gathering floating body and has necessary insulation and waterproof properties.

[0036] The main structure of the power generation equipment 18 includes a stator coil 18-1, a permanent magnet pole 18-2, a reel 18-3 and a rope guide 18-4, each of which is two groups. The permanent magnet pole 18-2 is coaxial with the reel 18-3, and the rope guide 18-4 is used to arrange the pull rope 17 neatly on the reel 18-3. In specific operation, the pull rope 17 connected to the oscillating float 6 drags the reel 18-3 to rotate through the pulleys 15 and 16, thereby driving the permanent magnet pole 18-2 to rotate around the stator coil 18-1 to achieve power generation.

[0037] In the embodiment of the present invention, four groups of anchor systems 21, 22, 23 and 24 are included. The anchor cables of the four groups of anchor systems 21, 22, 23 and 24 respectively connect the end corners of the wave-gathering buoys 3 and 4 to the seabed, so as to fix the entire system at a specified sea surface position and significantly reduce the oscillation amplitude of the wave-gathering buoys 3 and 4 under wave excitation.

[0038] In a specific embodiment, the dimensions, masses, materials, working parameters, etc. of the main structures adopted by the present invention, such as the vertical walls 1, 2, wave-gathering floats 3, 4, oscillating floats 6, supporting structures 7, 8, pull ropes 17 and power generation equipment 18, can be adjusted according to the wave conditions of the sea area where it is used. Since the entire device is a floating structure, it has good adaptability to the water depth of the working waters.

[0039] Compared with the existing technology, the present invention has the significant advantages of novel principle, simple structure, low construction cost and wide adaptability. It can make full use of dispersed, low energy flow density wave energy, improve the economy and efficiency of wave energy conversion, and realize the full, economical and efficient utilization of low-grade renewable energy with low resource utilization value.

[0040] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A narrow-slit wave-focusing high-efficiency wave energy absorption device, characterized in that: It includes vertical walls, a wave-gathering float, an oscillating float, a pull rope, a pulley, a positioning rod, a supporting structure and a power generation device; two groups of vertical walls form a contraction wave channel structure that gradually narrows in the direction of wave propagation; the positioning rod is connected to the oscillating float as a whole, and the supporting structure is symmetrically installed on the upper and lower sides of the wave-gathering float. There are four groups of positioning rods, one end of which is connected to the oscillating float as a whole, and the other end passes through a positioning hole set on the supporting structure and slides freely in the positioning hole; the pulley is installed on the supporting structure, and the two ends of the pull rope are connected to the oscillating float and bypass the two groups of pulleys symmetrically arranged up and down to drive the power generation device to generate electricity, and the power generation device is installed on the wave-gathering float; the wave-gathering float floats on the wave surface, and there is a narrow rectangular slit in the middle of the wave-gathering float along the wave propagation direction; the oscillating float is a rectangular float, and its length and width are slightly smaller than the corresponding sizes of the slit, and its thickness and draft are consistent with those of the wave-gathering float, and the oscillating float is set in the slit.

2. The narrow-slit wave focusing type high-efficiency wave energy absorption device according to claim 1 is characterized in that: The wave-aggregating water channel composed of two groups of symmetrically arranged vertical walls is connected to the front of the wave-aggregating buoy through a hinge, and the angle can be changed within the range of 30° to 60° according to the wave conditions.

3. The narrow-slit wave focusing type high-efficiency wave energy absorption device according to claim 1 is characterized in that: The pull rope is elastic and self-tightening, and its two ends are connected to the upper and lower sides of the oscillating float through pulleys. The pull rope is pulled back and forth by the oscillating float in the vertical swinging motion, dragging the power generation equipment to generate electricity.

4. The narrow-slot wave focusing type high-efficiency wave energy absorption device according to claim 1 is characterized in that: Four groups of return springs are also provided and sleeved on the corresponding four groups of positioning rods, and two ends of the return springs are respectively fixed on the positioning holes and the positioning rods.

5. The narrow-slit wave-focusing high-efficiency wave energy absorbing device according to any one of claims 1 to 4, characterized in that: It also includes four groups of anchoring systems, the anchor cables of which respectively connect the four end corners of the wave-aggregating buoy to the seabed, so as to fix the whole system at a designated sea surface position and reduce the vibration of the wave-aggregating buoy.

6. The narrow-slit wave focusing type high-efficiency wave energy absorption device according to any one of claims 1 to 4, characterized in that: The immersion depth d of the wave-aggregating buoy is between 1 / 2 of the wave height H and 1 / 8 of the wavelength λ.

7. The narrow-slit wave focusing type high-efficiency wave energy absorption device according to any one of claims 1 to 4, characterized in that: The relationship between the width s of the narrow slot perpendicular to the wave crest line and the total width L of the wave gathering floating body perpendicular to the wave crest line satisfies the following condition: 0.037≤s / L≤0.070.

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