Double-layer open-pore caisson type oscillating water column wave energy collection device and design method

Abstract

The application provides a double-layer perforated caisson type oscillating water column wave energy collecting device and a design method, and relates to the technical field of coastal engineering. In view of the problem that the prior art is difficult to balance the structural simplicity, wide frequency adaptation and efficient wave energy utilization, the double-layer perforated caisson type oscillating water column wave energy collecting device comprises a caisson body, a front layer compartment, a rear layer compartment, a partition plate and an oscillating water column power generation assembly. The front layer compartment and the rear layer compartment are arranged in the caisson body and are communicated with the oscillating cavity of the caisson body. The double-layer compartments are provided with water inlet holes. The partition plate is arranged between the two compartments, the partition plate is provided with through holes, the size of the through holes is adapted to the change of the wave frequency, the through holes are used for passing or throttling water, and the two compartments are coupled to oscillate or independently oscillate. The oscillating water column power generation assembly collects the wave energy generated when the front layer compartment and the rear layer compartment oscillate, and converts the wave energy into electric energy. The device has the advantages of simple structure, wide frequency adaptation and efficient wave energy utilization.

Description

Technical Field

[0001] This invention relates to the field of coastal engineering technology, and in particular to a double-layer perforated caisson type oscillating water column wave energy harvesting device and its design method. Background Technology

[0002] Oscillating Water Column (OWC) wave energy devices are one of the most technologically mature and widely used forms of shore-based wave energy utilization. They rely on an open caisson structure and use the oscillation of the air column inside the caisson under the action of waves to drive an air turbine to generate electricity.

[0003] In existing technologies, perforated caisson-type oscillating water column wave energy harvesting devices mostly adopt a single-layer, single-cell structure. A fixed opening and a single oscillating air chamber are only located on the wave-facing side of the caisson. The water inside the air chamber rises and falls repeatedly, and the compressed air in the chamber drives an air turbine to convert wave energy into electrical energy. These traditional devices have a simple chamber layout and fixed baffle and opening parameters, making them unable to adapt to the wide frequency variations of waves in the ocean. Furthermore, they have high wave reflectivity and poor adaptability to water level changes. To improve upon the shortcomings of traditional perforated caisson-type oscillating water column devices, proposed improvements include: a controllable caisson with actively adjustable opening area via hydraulic gates or other mechanisms; an oscillating water column structure with multiple air chambers arranged in series; and a composite structure combining wave-damping walls and oscillating water columns. However, the controllable opening scheme has a complex control system and is difficult to maintain under marine conditions; the multi-air chamber series structure is complex; and the wave-damping wall composite structure focuses on wave-damping functionality but fails to achieve efficient wave energy capture and wave dissipation in synergy. Existing open-chamber type oscillating water column wave energy harvesting devices cannot simultaneously achieve structural simplicity, wide frequency adaptability, and efficient wave energy utilization.

[0004] Therefore, developing a double-layer perforated caisson-type oscillating water column wave energy harvesting device and its design method is of great significance for balancing structural simplicity, wide frequency adaptability and efficient wave energy utilization. Summary of the Invention

[0005] To address the challenge of simultaneously achieving structural simplicity, wideband compatibility, and efficient wave energy utilization in existing technologies, this invention proposes a double-layered, perforated caisson-type oscillating water column wave energy harvesting device. The device comprises: a caisson body, a front chamber, a rear chamber, a partition, and an oscillating water column power generation component. The front and rear chambers are disposed within the caisson body, with the front chamber closer to the wave-facing side and the rear chamber further away. The tops of both chambers are connected to the oscillation cavity of the caisson body. Water inlets are provided on the wave-facing sides of both chambers. The partition is positioned between the front and rear chambers, and has through holes of varying sizes adapted to wave frequency changes. These through holes allow water to pass through or be diverted, enabling the front and rear chambers to oscillate in a coupled or independent manner. The oscillating water column power generation component is connected to the oscillation cavity via an air duct. This component collects the pressure energy generated during oscillation and converts it into electrical energy.

[0006] Furthermore, the vertical height of the water inlet of the front cell corresponds to the range from low tide to average water level in the target sea area, and the vertical height of the water inlet of the rear cell corresponds to the range from average water level to high tide in the target sea area.

[0007] Furthermore, the horizontal width of the water inlet hole of the front compartment satisfies the following condition: B1=λ min / 4; Where B1 represents the horizontal width of the inlet hole of the front cell, λ min This indicates the wavelength corresponding to the shortest design wave period in the target sea area; The horizontal width of the water inlet hole of the rear compartment must meet the following condition: B2=λ max / 4; Where B2 represents the horizontal width of the water inlet hole in the rear cell, λ max This indicates the wavelength corresponding to the longest design wave period in the target sea area.

[0008] Furthermore, the vertical height of the through hole is 0.1-0.3 times the net depth of the caisson. The through hole is used to create coupled oscillations between the bottom water of the front and rear cells under the action of low-frequency long-period waves, and to generate a throttling effect under the action of high-frequency short-period waves, so that the front and rear cells can respond independently.

[0009] Furthermore, the oscillating water column power generation component includes a Wells turbine power generation module and a control module. The control module is used to acquire the air pressure difference signal in the oscillation cavity, calculate the target rotation speed based on the air pressure difference signal, and drive the Wells turbine power generation module to operate at the target rotation speed.

[0010] Furthermore, the sampling frequency of the control module when acquiring the gas pressure difference signal in the oscillation cavity meets the preset sampling frequency range.

[0011] Furthermore, the caisson body is a reinforced concrete structure.

[0012] This invention also provides a design method for a double-layer perforated caisson-type oscillating water column wave energy harvesting device. The design method is used to design the double-layer perforated caisson-type oscillating water column wave energy harvesting device described in any of the above claims. The design method includes: S1. Collect historical wave observation data for the target sea area to determine the baseline water level and wave condition combination; S2. Combining historical wave observation data, benchmark water level and geometric parameters of the caisson body, a wave response numerical model is established based on potential flow theory, and the radiation potential and diffraction potential are solved by boundary element method or finite element method. S3. Based on the radiation potential and diffraction potential, construct the correlation function between the resonant frequency of the oscillation cavity and the relevant parameters of the front cell, the rear cell and the partition. S4. To maximize the weighted average of the capture width ratio of the oscillation cavity, minimize the wave reflection coefficient, and maximize the retention rate of the effective opening area under different reference water levels, a multi-objective optimization function model is established, and the optimization search intervals for each parameter of the front and rear cells are set. S5. Using a multi-objective genetic algorithm, the multi-objective optimization model is iteratively solved within the optimization search interval to determine the final parameter scheme; S6. Based on the final parameter scheme, create a physical model of the device with a preset scale, conduct wave tests to verify it, and adjust the parameters according to the actual wave conditions during the test. S7. Perform an overall stability check on the physical model of the device after parameter adjustment.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The double-layer perforated caisson-type oscillating water column wave energy collection device provided by the present invention includes: a caisson body, a front chamber, a rear chamber, a partition, and an oscillating water column power generation component; the front chamber and the rear chamber are disposed within the caisson body, with the front chamber closer to the wave-facing side and the rear chamber farther from the wave-facing side, and the tops of both the front and rear chambers are connected to the oscillation cavity of the caisson body; water inlets are provided on the wave-facing sides of both the front and rear chambers; the partition is disposed between the front and rear chambers, and through holes are provided on the partition, the size of which is adapted to changes in wave frequency, and the through holes are used to allow or throttle water flow, so that the front and rear chambers can oscillate in a coupled manner or oscillate independently; the oscillating water column power generation component is connected to the oscillation cavity through an air duct, and is used to collect the air pressure energy generated during the oscillation of the oscillation cavity and convert the air pressure energy into electrical energy. By setting through-holes in the partition plate to connect the front and rear chambers, and controlling the flow of water through these through-holes, the two chambers can switch between coupled or independent oscillation according to the wave frequency, thus widening the resonant frequency band and adapting to complex wave conditions. The entire device only requires a simple partition plate opening structure, eliminating the need for complex control components, resulting in a concise structure. Simultaneously, the water oscillation in the two chambers can enhance cavity pressure, reduce wave reflection, and improve wave energy capture capability. Therefore, the double-layered perforated caisson-type oscillating water column wave energy harvesting device provided by this invention can achieve a balance between structural simplicity, wide frequency band adaptability, and efficient wave energy utilization. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a double-layer perforated caisson-type oscillating water column wave energy collection device provided in an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of a double-layer perforated caisson-type oscillating water column wave energy harvesting device provided in an embodiment of the present invention; Figure 3 This is a comparison diagram of the resonant frequency coverage range between the front and rear cell layers provided in an embodiment of the present invention; Figure 4 This is a performance comparison diagram between the double-layer perforated caisson provided in this embodiment of the invention and the traditional single-perforated caisson; Figure 5 This is a flowchart of a design method for a double-layer perforated caisson-type oscillating water column wave energy harvesting device provided in an embodiment of the present invention.

[0016] Figure label: 1-Sediment box body, 2-Front compartment, 3-Rear compartment, 4-Baffle, 41-Through hole, 5-Oscillating water column power generation component, 6-Oscillating cavity, 7-Air duct, 8-Water inlet, 9-Base. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0018] The specific embodiments of the present invention will be described below.

[0019] To address the challenge of simultaneously achieving structural simplicity, wideband compatibility, and efficient wave energy utilization in existing technologies, this invention provides a double-layered perforated caisson-type oscillating water column wave energy harvesting device. The device comprises a caisson body, a front chamber, a rear chamber, a partition, and an oscillating water column power generation component. The front and rear chambers are located within the caisson body and are both connected to the oscillation chamber of the caisson body. Both chambers are equipped with water inlets. The partition is positioned between the two chambers and features through-holes. The through-hole size adapts to changes in wave frequency and allows water to flow through or be diverted, enabling the two chambers to oscillate coupledly or independently. The oscillating water column power generation component collects the wave energy generated during the oscillation of the front and rear chambers and converts it into electrical energy. This invention offers a simple structure and the advantages of wideband compatibility and efficient wave energy utilization.

[0020] Example 1 This invention provides a double-layer perforated caisson-type oscillating water column wave energy harvesting device. Figure 1 This is a schematic diagram of the structure of a double-layer perforated caisson-type oscillating water column wave energy harvesting device provided in an embodiment of the present invention. Figure 2 This is a cross-sectional schematic diagram of a double-layer perforated caisson-type oscillating water column wave energy harvesting device provided in an embodiment of the present invention, as shown below. Figure 1 and Figure 2As shown, the double-layer perforated caisson-type oscillating water column wave energy collection device includes: a caisson body 1, a front chamber 2, a rear chamber 3, a partition 4, and an oscillating water column power generation component 5; the front chamber 2 and the rear chamber 3 are located inside the caisson body 1, with the front chamber 2 closer to the wave-facing side and the rear chamber 3 further away from the wave-facing side, and the tops of both the front chamber 2 and the rear chamber 3 are connected to the oscillation cavity 6 of the caisson body; water inlets are provided on the wave-facing sides of both the front chamber 2 and the rear chamber 3; the partition 4 is located between the front chamber and the rear chamber, and a through hole 41 is provided on the partition 4. The size of the through hole is adapted to the wave frequency change, and the through hole is used to allow water to pass through or throttle, so that the front chamber 2 and the rear chamber 3 can oscillate in a coupled manner or oscillate independently; the oscillating water column power generation component 5 is connected to the oscillation cavity 6 through an air passage 7, and the oscillating water column power generation component 5 is used to collect the air pressure energy generated during the oscillation of the oscillation cavity and convert the air pressure energy into electrical energy.

[0021] The caisson, serving as the main body of the device and a coastal breakwater unit, can be assembled along the shoreline. It supports the front and rear chambers, baffles, and the oscillating water column power generation components. The caisson is a reinforced concrete structure, prefabricated integrally with the front and rear chambers and baffles. The front chamber refers to an independent, open-cell structure near the wave-facing side, receiving incident waves through wave-facing inlet 8 to provide water for the internal water column oscillation. The rear chamber refers to an independent, open-cell structure away from the wave-facing side, receiving incident waves through wave-facing inlet 8 to provide water for the internal water column oscillation. The baffle is a vertical plate separating the front and rear chambers, with through-holes at the bottom, allowing for throttling or conduction under different wave conditions based on its dimensions. The oscillation chamber is an air chamber at the top of the caisson, accommodating the reciprocating oscillation of the air column to convert wave energy into air pressure energy. The air duct is the airflow channel connecting the oscillation chamber and the oscillating water column power generation components, used to transmit air pressure. The oscillating water column power generation component is the core actuator that converts air pressure energy into electrical energy. It receives the alternating air pressure generated by the oscillation cavity and optimizes the power generation efficiency in real time, completing the conversion and output of wave energy into electrical energy.

[0022] Waves enter two independent water chambers through the wave-facing inlets of the front and rear chambers, respectively. The water in both chambers rises and falls with the waves, jointly driving the air column in the shared oscillation chamber at the top to reciprocate through compression and expansion, creating alternating air pressure. This air pressure is transmitted through air channels to the oscillating water column power generation component, which outputs electrical energy. The through-holes on the partition are designed according to the wave frequency characteristics, allowing for differentiated hydrodynamic effects on waves of different frequencies. Under the action of low-frequency, long-period waves, the water movement period is long and the flow velocity is slow, resulting in low resistance from the through-holes and smooth communication between the bottom water of the front and rear chambers, forming coupled oscillations. Under the action of high-frequency, short-period waves, the water movement period is short and the flow velocity is fast, causing the through-holes to create a throttling effect, restricting the rapid exchange of water between the two chambers, thus decoupling the front and rear chambers and allowing them to oscillate independently.

[0023] The double-layer perforated caisson-type oscillating water column wave energy harvesting device provided in this embodiment includes: a caisson body, a front chamber, a rear chamber, a partition, and an oscillating water column power generation component; the front chamber and the rear chamber are disposed within the caisson body, with the front chamber closer to the wave-facing side and the rear chamber farther from the wave-facing side, and the tops of both the front and rear chambers are connected to the oscillation cavity of the caisson body; water inlets are provided on the wave-facing sides of both the front and rear chambers; the partition is disposed between the front and rear chambers, and through holes are provided on the partition, the size of which is adapted to changes in wave frequency, and the through holes are used to allow or throttle water flow, so that the front and rear chambers can oscillate in a coupled manner or oscillate independently; the oscillating water column power generation component is connected to the oscillation cavity through an air duct, and the oscillating water column power generation component is used to collect the air pressure energy generated during the oscillation of the oscillation cavity and convert the air pressure energy into electrical energy. By incorporating through-holes in the baffle plate to connect the front and rear chambers, and controlling the flow of water through these holes, the two chambers can switch between coupled or independent oscillation according to the wave frequency. This broadens the resonant frequency band and adapts to complex wave conditions. The entire device only requires a simple baffle plate opening structure, eliminating the need for complex control components, resulting in a concise structure. Simultaneously, the water oscillation in the two chambers enhances cavity pressure, reduces wave reflection, and improves wave energy capture capability. Therefore, the double-layered perforated caisson-type oscillating water column wave energy harvesting device provided in this embodiment achieves a balance between structural simplicity, wide frequency band adaptability, and efficient wave energy utilization.

[0024] Specifically, the vertical height of the inlet holes of the front chamber corresponds to the range from low tide to average water level in the target sea area, while the vertical height of the inlet holes of the rear chamber corresponds to the range from average water level to high tide in the target sea area.

[0025] The low tide to mean water level range of the target sea area refers to the low water level operating range obtained from long-term observation and statistics of the target sea area. The inlet holes of the front chamber are completely submerged within this range to ensure effective water intake under low tide conditions. The mean water level to high tide range of the target sea area refers to the high water level operating range obtained from long-term observation and statistics of the target sea area. The inlet holes of the rear chamber are completely submerged within this range to ensure effective water intake under high tide conditions. The vertical height of the inlet holes refers to the vertical arrangement range of the inlet holes on the wave-facing sidewall of the caisson, relying on fixed positions to match the effective water passage cross-section under different tide levels.

[0026] During tidal changes in the target sea area, waves in the low tide to mean water level range mainly enter the front chamber through the inlet holes corresponding to this water level range, forming water column oscillations. Waves in the mean water level to high tide range mainly enter the rear chamber through the inlet holes corresponding to this water level range, forming water column oscillations. The two layers of inlet holes are arranged according to water level, ensuring that the device maintains a stable water flow section and effective water intake throughout the low tide, mean water level, and high tide ranges, continuously driving the oscillation chamber to generate air pressure and generate electricity.

[0027] Specifically, the horizontal width of the inlet hole of the front cell must meet the following conditions: B1=λ min / 4; Where B1 represents the horizontal width of the inlet hole of the front cell, λ min This indicates the wavelength corresponding to the shortest design wave period for the target sea area.

[0028] The horizontal width of the inlet hole of the rear compartment must meet the following condition: B2=λ max / 4; Where B2 represents the horizontal width of the water inlet hole in the rear cell, λ max This indicates the wavelength corresponding to the longest design wave period in the target sea area.

[0029] The horizontal width of the inlet hole refers to the dimension of the inlet hole on the wave-facing side of the caisson along the horizontal depth direction, directly determining the resonance scale of the caisson. The shortest design wave period for the target sea area refers to the lower limit of the wave period obtained statistically for the target sea area, and the longest design wave period refers to the upper limit of the wave period obtained statistically for the target sea area. For example, if the multi-year average water level of the target sea area is 2.5m, the low tide level is 1.6m, the high tide level is 3.4m, the tidal range is 1.8m, the wave period distribution range is 2-8s, the significant wave height is 0.5-3.0m, the lower limit of the wave period T10% = 3s, and the upper limit of the wave period T90% = 7s.

[0030] When high-frequency, short-period waves are incident, their short wavelengths match the resonant scale of the front cell, causing it to resonate and efficiently capture short-wave energy. In contrast, the rear cell, due to its larger width, does not match the short-wave resonant scale and exhibits a weaker response. Conversely, when low-frequency, long-period waves are incident, their longer wavelengths match the resonant scale of the rear cell, causing it to dominate the resonance and efficiently capture long-wave energy. The response of the front cell weakens. Through differentiated fixed-width designs, the two cell layers respectively cover the resonant ranges of short and long waves. Combined with the coupling or decoupling effect of the partition openings, they jointly achieve a full-coverage response for broadband waves.

[0031] By designing the horizontal width of the inlet hole, the resonance peaks of the two-cell structure are anchored at the shortest and longest wave cycles of the design sea area, respectively, so that the resonant frequency of the oscillation cavity covers more than 80% of the design wave cycle, and the broadband adaptability is improved by about 40% compared with the traditional solution. Figure 3 This is a comparison diagram of the resonant frequency coverage range between the front and rear cell layers provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the resonant frequency coverage of the oscillation cavity is 87%. Combined with the water level adaptability of the layered vertical openings, it further ensures effective energy capture across all tide levels and the entire design cycle, increasing the average annual power generation of the device by about 35% compared to traditional single-opening caissons. Moreover, it does not require additional movable adjustment structures, maintaining the simplicity and reliability of integration with the breakwater.

[0032] Based on the above embodiments, the vertical height of the through hole is 0.1-0.3 times the net depth of the caisson. The through hole is used to create coupled oscillations between the bottom water of the front and rear cells under the action of low-frequency long-period waves, and to generate a throttling effect under the action of high-frequency short-period waves, so that the front and rear cells can respond independently.

[0033] The net depth of the caisson refers to the vertical depth from the bottom plate to the bottom of the oscillation chamber. When subjected to low-frequency, long-period waves, the wave motion is gentle, and the water level rise and fall in the front and rear chambers is slow. In this case, a through-hole set at 0.1 to 0.3 times the net depth of the caisson provides sufficient flow capacity, allowing water to freely exchange at the bottom of the two chambers, resulting in coupled oscillation between the front and rear chambers. When subjected to high-frequency, short-period waves, the wave undulations are violent, and the through-hole is relatively narrow. The flow through this through-hole creates a throttling effect, insufficient to support rapid water exchange between the two chambers, thus hindering the synchronous movement of the water columns in both chambers. This causes the front and rear chambers to respond independently, avoiding mutual interference.

[0034] By setting the vertical height of the through hole, the capture bandwidth for low-frequency waves is broadened through coupled oscillation under long waves, and the independent resonance efficiency of the double-layer cell is ensured through the throttling effect under short waves. The frequency division response problem that traditional multi-chamber devices require complex control to achieve is solved by using only holes of fixed size. Figure 4 This is a performance comparison diagram between the double-layer perforated caisson provided in this embodiment of the invention and the traditional single-perforated caisson, as shown in the figure. Figure 4 As shown, in this embodiment, the structure, combined with double-layer openings, reduces the wave reflection coefficient to below 13%, while avoiding the high cost of multiple independent turbine systems, thus achieving a balance between wideband high-efficiency power generation, simple structure, and low cost.

[0035] The oscillating water column power generation assembly includes a Wells turbine power generation module and a control module. The control module is used to acquire the air pressure difference signal inside the oscillation cavity, calculate the target rotational speed based on the air pressure difference signal, and drive the Wells turbine power generation module to operate at the target rotational speed. The acquisition frequency of the air pressure difference signal acquired by the control module within the oscillation cavity meets a preset sampling frequency range.

[0036] The Wells turbine power generation module is the core energy conversion unit of the oscillating water column power generation system. It consists of a bidirectional pneumatic turbine, a generator, and transmission components. Under the influence of the reciprocating alternating airflow generated in the oscillation chamber, it maintains unidirectional rotation, stably converting wave energy into pressure energy and then into electrical energy. The control module is the intelligent control core of the oscillating water column power generation system, employing the Maximum Power Point Tracking (MPPT) algorithm to calculate the target rotational speed. The pressure difference signal refers to the pressure difference between the inside of the oscillation chamber and the external atmospheric pressure, reflecting the intensity of the water column oscillation. The target rotational speed refers to the optimal turbine speed that best suits the current wave conditions and maximizes power generation efficiency. The preset sampling frequency range is a signal acquisition speed range pre-set by the control module to ensure real-time and accurate capture of pressure changes. For example, the preset sampling frequency range is a sampling frequency of no less than 10Hz.

[0037] The control module acquires the air pressure difference signal within the oscillation cavity in real time at a frequency of no less than 10Hz. Based on the acquired dynamic air pressure data, it analyzes the maximum power point under the current wave conditions online using the disturbance observation method, and calculates the target speed that maximizes the turbine's output power. By sending a command to the variable frequency speed control device, the Wells turbine power generation module is driven to adjust to the target speed, ensuring that the turbine dynamically adjusts its operating state in accordance with wave changes. By acquiring the air pressure difference in real time and dynamically adjusting the turbine speed, the power generation components always operate at the optimal efficiency point under varying wave conditions, improving power generation efficiency and average annual power generation.

[0038] Example 2 This invention also provides a design method for a double-layer perforated caisson-type oscillating water column wave energy harvesting device, which designs the double-layer perforated caisson-type oscillating water column wave energy harvesting device according to any of the above embodiments. Figure 5 This is a flowchart illustrating the design method of a double-layer perforated caisson-type oscillating water column wave energy harvesting device provided in an embodiment of the present invention. Figure 5 As shown, the design method includes: S1. Collect historical wave observation data for the target sea area to determine the baseline water level and wave condition combination; S2. Combining historical wave observation data, benchmark water level and geometric parameters of the caisson body, a wave response numerical model is established based on potential flow theory, and the radiation potential and diffraction potential are solved by boundary element method or finite element method. S3. Based on the radiation potential and diffraction potential, construct the correlation function between the resonant frequency of the oscillation cavity and the relevant parameters of the front cell, the rear cell and the partition. S4. To maximize the weighted average of the capture width ratio of the oscillation cavity, minimize the wave reflection coefficient, and maximize the retention rate of the effective opening area under different reference water levels, a multi-objective optimization function model is established, and the optimization search intervals for each parameter of the front and rear cells are set. S5. Using a multi-objective genetic algorithm, the multi-objective optimization model is iteratively solved within the optimization search interval to determine the final parameter scheme; S6. Based on the final parameter scheme, create a physical model of the device with a preset scale, conduct wave tests to verify it, and adjust the parameters according to the actual wave conditions during the test. S7. Perform an overall stability check on the physical model of the device after parameter adjustment.

[0039] The reference water level is a representative control water level determined based on long-term observation data of the target sea area, used for device design and verification. It specifically includes low tide, mean water level, and high tide. Wave condition combinations refer to a set of representative wave conditions determined based on the statistical characteristics of waves in the target sea area. For example, wave periods T are 3s, 5s, and 7s, and significant wave heights Hs are 1.0m, 2.0m, and 3.0m, resulting in nine wave condition combinations. Potential flow theory is the fundamental fluid dynamics theory used to calculate the interaction between waves and a double-layered perforated caisson. By assuming the fluid is inviscid, irrotational, and possesses velocity potential, it simplifies the flow field calculations for wave diffraction, radiation, and water oscillation. The wave response numerical model is a numerical calculation model used to predict water column oscillation, air pressure, and reflection coefficient inside the caisson. Radiation potential and diffraction potential are two core physical quantities in potential flow theory describing the interaction between waves and structures. Radiation potential describes the waves radiated by structural oscillations, while diffraction potential describes the deformation of waves as they bypass a stationary structure; together, they determine the structural stress and wave reflection characteristics. The capture width ratio is a core indicator for measuring wave energy capture efficiency. It refers to the ratio of actual captured power to incident wave power per unit wave crest width. Weighted mean maximization aims to maximize the average capture width ratio after weighting by the probability of occurrence for different wave conditions, ensuring optimal overall power generation capacity of the device across all wave conditions. Effective orifice area retention rate refers to the proportion of orifice area that can normally allow water inflow at all tide levels to the total orifice area. Preset scale ratio is a fixed scaling ratio between the prototype device and the test model, pre-set before physical model testing; for example, a preset scale ratio of 1:20.

[0040] Collect wave observation data for at least 10 years in the target sea area to determine three benchmark water levels (low, medium, and high) and representative wave condition combinations. Establish a numerical model of wave response based on potential flow theory, solve for radiation and diffraction potentials using the boundary element method, and construct a correlation function between the resonant frequency of the oscillation cavity and parameters such as the width of the double-layer cell, the location of the opening, and the height of the diaphragm connection. Establish a multi-objective optimization model with the goals of maximizing power generation efficiency, achieving the best wave dissipation effect, and maximizing adaptability across all tide levels. Define the search range for each parameter and use the NSGA-II multi-objective genetic algorithm to iteratively optimize within the search range, selecting the final parameter scheme that balances performance and engineering feasibility. Create a physical model of the device at a 1:20 scale and conduct experimental verification under representative wave conditions in a wave tank, fine-tuning the parameters based on actual wave conditions. Perform overall stability checks on the adjusted device, including anti-sliding, anti-overturning, and foundation bearing capacity, to ensure structural safety meets standards.

[0041] This embodiment relies on actual sea area measurement data for preliminary planning, and combines potential flow theory to build a wave response numerical model, completing hydrodynamic simulation calculations to accurately determine the intrinsic relationship between structural parameters and device resonance characteristics. By constructing a multi-objective optimization model and employing a multi-objective genetic algorithm for optimization, taking into account wave energy capture efficiency, coastal wave dissipation effect, and adaptability to all tide levels, the optimal combination of structural parameters with comprehensive performance is obtained. Based on scaled-down model wave tests, on-site operating condition simulation verification is completed, promptly correcting deviations between theoretical design and practical application, and further optimizing structural detail parameters. Through overall stability verification, the safe use of the device in complex marine environments can be fully guaranteed.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A double-layer perforated caisson-type oscillating water column wave energy harvesting device, characterized in that, include: The caisson body, the front compartment, the rear compartment, the partition, and the oscillating water column power generation components; The front compartment and the rear compartment are located inside the caisson. The front compartment is closer to the wave-facing side, and the rear compartment is farther from the wave-facing side. The tops of both the front and rear compartments are connected to the oscillation chamber of the caisson. Water inlets are provided on the wave-facing side of both the front and rear compartments. The partition is disposed between the front cell and the rear cell, and the partition is provided with through holes. The size of the through holes is adapted to the wave frequency change. The through holes are used to allow water to pass through or to throttle the water, so that the front cell and the rear cell can oscillate in a coupled manner or oscillate independently. The oscillating water column power generation component is connected to the oscillation cavity through an air passage. The oscillating water column power generation component is used to collect the air pressure energy generated when the oscillation cavity oscillates and convert the air pressure energy into electrical energy.

2. The double-layer perforated caisson-type oscillating water column wave energy harvesting device according to claim 1, characterized in that, The vertical height of the inlet hole of the front cell corresponds to the range from low tide to average water level in the target sea area, and the vertical height of the inlet hole of the rear cell corresponds to the range from average water level to high tide in the target sea area.

3. The double-layer perforated caisson-type oscillating water column wave energy harvesting device according to claim 2, characterized in that, The horizontal width of the water inlet hole of the front compartment must meet the following condition: B1=λ min / 4; Where B1 represents the horizontal width of the inlet hole of the front cell, λ min This indicates the wavelength corresponding to the shortest design wave period in the target sea area; The horizontal width of the water inlet hole of the rear compartment must meet the following condition: B2=λ max / 4; Where B2 represents the horizontal width of the water inlet hole in the rear cell, λ max This indicates the wavelength corresponding to the longest design wave period in the target sea area.

4. The double-layer perforated caisson-type oscillating water column wave energy harvesting device according to claim 1, characterized in that, The vertical height of the through hole is 0.1-0.3 times the net depth of the caisson. The through hole is used to create coupled oscillations between the bottom water of the front and rear cells under the action of low-frequency long-period waves, and to generate a throttling effect under the action of high-frequency short-period waves, so that the front and rear cells can respond independently.

5. The double-layer perforated caisson-type oscillating water column wave energy harvesting device according to claim 1, characterized in that, The oscillating water column power generation component includes a Wells turbine power generation module and a control module. The control module is used to acquire the air pressure difference signal in the oscillation cavity, calculate the target rotation speed based on the air pressure difference signal, and drive the Wells turbine power generation module to run at the target rotation speed.

6. The double-layer perforated caisson-type oscillating water column wave energy harvesting device according to claim 5, characterized in that, The sampling frequency of the control module when acquiring the air pressure difference signal in the oscillation cavity meets the preset sampling frequency range.

7. The double-layer perforated caisson-type oscillating water column wave energy harvesting device according to claim 1, characterized in that, The caisson body is a reinforced concrete structure.

8. A design method for a double-layer perforated caisson-type oscillating water column wave energy harvesting device, characterized in that, The design method described above is used to design the double-layer perforated caisson-type oscillating water column wave energy harvesting device according to any one of claims 1-7. The design method includes: S1. Collect historical wave observation data for the target sea area to determine the baseline water level and wave condition combination; S2. Combining historical wave observation data, benchmark water level and geometric parameters of the caisson body, a wave response numerical model is established based on potential flow theory, and the radiation potential and diffraction potential are solved by boundary element method or finite element method. S3. Based on the radiation potential and diffraction potential, construct the correlation function between the resonant frequency of the oscillation cavity and the relevant parameters of the front cell, the rear cell and the partition. S4. To maximize the weighted average of the capture width ratio of the oscillation cavity, minimize the wave reflection coefficient, and maximize the retention rate of the effective opening area under different reference water levels, a multi-objective optimization function model is established, and the optimization search intervals for each parameter of the front and rear cells are set. S5. Using a multi-objective genetic algorithm, the multi-objective optimization model is iteratively solved within the optimization search interval to determine the final parameter scheme; S6. Based on the final parameter scheme, create a physical model of the device with a preset scale, conduct wave tests to verify it, and adjust the parameters according to the actual wave conditions during the test. S7. Perform an overall stability check on the physical model of the device after parameter adjustment.

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