A back-bent pipe wave energy power generation buoy and its air turbine switching device and method

Abstract

The present application relates to the field of wave energy generating buoy, disclose a kind of after bending pipe wave energy generating buoy and its air turbine switching device and method.For the defects that the existing single turbine buoy can only adapt to specific wave frequency, wide operating condition, low power generation efficiency, and easy to overload damage in extreme sea conditions, the present application connects wiles turbine and impact turbine at the end of single after bending pipe air path, real-time monitoring of wave frequency by wave frequency sensor, sliding guide cover driven by motor driving screw rod, to realize the adaptive switching of two turbines.When the wave frequency exceeds the effective range, the impact turbine is selected by default;In the effective range, greater than the threshold frequency selects the impact turbine, and less than the threshold frequency selects the wiles turbine.The present application combines the performance advantages of two turbines, the annual average power generation efficiency is improved by 32%, the turbine service life is extended to 8 years, the power supply reliability is more than 95%, and is suitable for power supply in offshore scenes such as islands and offshore platforms.

Description

Technical Field

[0001] This invention relates to the field of marine renewable energy utilization technology, specifically to the field of wave energy conversion device technology, and particularly to a back-curved tube wave energy power generation buoy and its air turbine switching device and method. Background Technology

[0002] Wave energy is one of the highest-quality renewable energy sources in the ocean, characterized by its green, clean, pollution-free, and sustainable nature. Globally, wave energy reserves are vast and widely distributed; with oceans covering 71% of the Earth's surface, it represents an inexhaustible resource. Compared to other renewable energy sources such as solar and wind power, wave energy boasts higher energy density and greater stability, unaffected by diurnal, seasonal, or weather changes. Furthermore, wave energy generation devices are mostly deployed on or underwater, minimizing the use of valuable land resources. It is highly compatible with marine industries such as fisheries, shipping, and offshore wind power, making it particularly suitable for providing stable power to offshore scenarios far from land-based power grids, such as islands, offshore platforms, marine observation stations, and underwater sensor networks. It is an ideal offshore complementary energy source, significantly enhancing the reliability and independence of marine energy systems.

[0003] Currently, wave energy buoys can be mainly classified into four categories according to their energy capture principles: oscillating water column buoys, oscillating float buoys, wave-overtaking buoys, and point-absorption buoys. Among them, oscillating water column buoys have become the most technologically mature and widely used type of wave energy buoy due to their advantages such as simple structure, high reliability, high peak energy capture, and low maintenance costs. The back-curved tube oscillating water column buoy is a typical example of an oscillating water column buoy. Its basic working principle is as follows: waves propel the floating back-curved tube to oscillate, which in turn causes the water column inside the L-shaped duct to oscillate violently up and down in the air chamber. The air inside the air chamber is compressed and drawn in by the water column, forming a continuous reciprocating high-pressure airflow. This airflow drives the air turbine to rotate, and finally, the generator connected to the turbine converts the rotational mechanical energy into electrical energy output.

[0004] To further improve the power generation efficiency of oscillating water column buoys, researchers both domestically and internationally have conducted extensive research, primarily focusing on optimizing the buoy's hydrodynamic characteristics. For example, patent CN118494679B discloses a wave energy power generation buoy and method with variable heave plate depth, which alters the buoy's hydrodynamic response characteristics by adjusting the heave plate depth; patent CN120039355B discloses a wave energy power generation buoy and its control method with variable length and angle damping plates, which optimizes the buoy's motion state by adjusting the damping plate parameters; and patent CN119929071B proposes a heave plate wave energy power generation buoy and method with variable water column cross-sectional area, which improves energy capture efficiency by changing the cross-sectional area of ​​the water column. While these existing technologies have improved the wave energy capture efficiency of buoys to some extent, none of them address the adaptability issue of the air turbine, the core energy conversion component, and cannot fundamentally solve the industry-wide common problem of poor adaptability of a single turbine across a wide range of operating conditions.

[0005] Air turbines are the core energy conversion components of oscillating water column wave energy buoys, and their performance directly determines the power generation efficiency and operational reliability of the entire device. Currently, the most widely used air turbines are Wells turbines and impulse turbines, whose performance is highly complementary: Wells turbines are self-rectifying turbines with symmetrical airfoil blades that can maintain unidirectional rotation under the action of reciprocating airflow without the need for additional rectification devices. They have extremely high energy conversion efficiency under medium-low flow rate and medium-high frequency wave conditions. However, Wells turbines have extremely poor overload capacity; when the airflow exceeds its rated value, the efficiency drops sharply, and the blades are easily damaged by excessive airflow impact. Impulse turbines, on the other hand, rely on airflow impact on the blades to generate rotational torque. They have excellent performance under high flow rate, low-frequency, large-amplitude wave conditions and strong overload capacity, capable of withstanding airflow impacts several times the rated flow. However, impulse turbines have extremely low efficiency under low flow rate conditions and cannot effectively utilize the energy of small waves.

[0006] Existing pneumatic wave energy buoys generally employ a single turbine configuration, which is only suitable for a specific wave frequency range. This results in a significant reduction in power generation efficiency under off-design conditions, with an overall annual average power generation efficiency of less than 25%. Furthermore, in extreme sea conditions such as typhoons and storm surges, the single Wells turbine is highly susceptible to overload damage, leading to system shutdown. This not only significantly shortens the turbine's lifespan and increases maintenance costs but also causes offshore power outages, severely impacting normal marine operations. Therefore, there is an urgent need to develop a back-bent tube wave energy buoy capable of automatically switching between air turbines based on real-time wave conditions. This buoy would combine the performance advantages of Wells turbines and impingement turbines to comprehensively improve the buoy's wide-range power generation efficiency and operational reliability, while extending the turbine's lifespan. Summary of the Invention

[0007] The purpose of this invention is to provide a back-curved wave energy power generation buoy and its air turbine switching device and method. This invention achieves adaptive switching between Wells turbine and impulse turbine through wave frequency feedback, combining the performance advantages of both to significantly improve power generation efficiency in all sea states, significantly extend turbine service life, reduce maintenance costs, and enhance the stability and reliability of power supply in offshore scenarios.

[0008] The technical solution adopted in this invention is as follows:

[0009] A backward-curved wave energy generating buoy includes an air turbine switching device and generators respectively connected to a Wells turbine and an impingement turbine. The air turbine switching device includes an L-shaped duct, an air chamber, and an air turbine. The L-shaped duct and the air chamber communicate to form a backward-curved tube, and an oscillating water column channel is formed inside the backward-curved tube. The air turbine includes a Wells turbine and an impingement turbine. The device also includes an inlet shroud, a flexible hose, a sliding guide shroud, an isolation shroud, a threaded screw, a drive motor, a wave frequency sensor, and a control unit. The backward-curved tube has two independent air outlets at its end, with the Wells turbine and the impingement turbine respectively installed at the two outlets. The inlet hood is fixed to the air inlet end of the air chamber, and the slidable guide hood is slidably disposed at the air outlet end of the air chamber. The inlet hood and the slidable guide hood are sealed and connected by a flexible hose. The isolation cover is fixed to the inner side of the end of the back bend and aligned with the two air outlets to separate the airflow channels of the two air outlets. The drive motor is connected to the slidable guide hood through a threaded screw and is used to drive the slidable guide hood to slide back and forth between the two air outlets to switch the airflow path. The wave frequency sensor is installed in the L-shaped duct. The wave frequency sensor and the drive motor are both electrically connected to the control unit. The control unit controls the drive motor to operate according to the wave frequency detected by the wave frequency sensor.

[0010] Preferably, the wave frequency sensor is installed in the middle of the horizontal section of the L-shaped duct 1, and the detection surface of the wave frequency sensor faces the wave direction.

[0011] Preferably, the inlet shroud is fixed to the upper part of the vertical pipe section of the air chamber, and the slidable guide shroud is slidably installed on the horizontal pipe section of the air chamber near the end.

[0012] Preferably, the output shaft of the drive motor is coaxially and fixedly connected to the threaded screw via a coupling, and the lower end of the slidable guide shield is threadedly connected to the threaded screw.

[0013] Preferably, at least one mooring ring is fixedly provided at the bottom of the L-shaped conduit for mooring and positioning of the buoy.

[0014] A switching method for an air turbine switching device of a wave energy power generation buoy with a curved tube as described above includes the following steps:

[0015] S1: Preset threshold frequency f(x), detection time interval T, and effective frequency upper limit f1 and effective frequency lower limit f2 for normal operation of the power generation device;

[0016] S2: Monitor the current wave frequency f(i) using a wave frequency sensor;

[0017] S3: Determine whether the current wave frequency f(i) is within the effective frequency range of [f2, f1];

[0018] S4: If f(i) exceeds the range of [f2,f1], the control unit controls the drive motor to switch the sliding guide shroud to the air outlet corresponding to the impact turbine; if f(i) is within the range of [f2,f1], compare the magnitude of f(i) with the threshold frequency f(x);

[0019] S5: If f(i) > f(x), switch to the air outlet corresponding to the impulsive turbine; if f(i) < f(x), switch to the air outlet corresponding to the Wells turbine.

[0020] S6: Repeat steps S2 to S5 at each time interval T.

[0021] Preferably, the threshold frequency f(x) in step S1 is determined based on a turbine efficiency comparison criterion, which is the intersection of the Wells turbine efficiency η_wells(f,H) and the impulse turbine efficiency η_impulse(f,H), where f is the wave frequency and H is the wave height.

[0022] Preferably, in steps S3 to S5, when the wave frequency sensor detects a wave frequency of 0.5~1.5Hz, an amplitude of 0.3~1.0m, and an airflow rate of 5~15m³ / h in the air chamber... 3 When the flow rate is / s, it is determined to be a medium-low flow, medium-high frequency operating condition, and the control is maintained or switched to Wells turbine; when the wave frequency sensor detects a wave frequency ≤0.5Hz, amplitude ≥1.0m and air chamber airflow ≥15m³ / s, 3 When the flow rate is / s, it is determined to be a high-flow, low-frequency, large-amplitude operating condition, and the control is maintained or switched to an impact turbine.

[0023] Preferably, in steps S4 and S5, the single switching action of the sliding fairing is completed within 1 second; after the switching is completed, the reciprocating airflow generated in the air chamber drives the generator to output electrical energy through the corresponding turbine.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention addresses the common industry shortcomings of existing pneumatic wave energy buoys, which generally employ a single turbine, are only adaptable to specific wave frequencies, have low power generation efficiency over a wide range of operating conditions, are prone to overload damage in extreme sea conditions, and have short service life. It proposes a dual-turbine adaptive switching scheme based on wave frequency feedback. By integrating a Wells turbine and an impulse turbine with complementary performance in parallel at the end of a single backward-curved tube oscillating water column air path, efficient power generation and turbine protection are achieved across all sea conditions, resulting in the following significant technical effects:

[0026] This invention combines the complementary advantages of Wells turbine's high efficiency at low flow rates and the superior performance of impingement turbines at high flow rates, adaptively covering the entire ocean wave frequency range of 0.1Hz to 2.0Hz. Prototype sea trials have verified that the annual average power generation efficiency of this invention can reach over 35%, representing a 32% improvement compared to traditional single Wells turbine power generation buoys. Specifically, under normal sea conditions with medium to low flow rates and medium to high frequency, the Wells turbine efficiency is ≥45%; under extreme sea conditions with high flow rates and low frequency with large amplitude, the impingement turbine efficiency is ≥40%, completely solving the problem of a sharp drop in efficiency of a single turbine under off-design conditions.

[0027] This invention automatically switches to a high-overload-capacity impact turbine under extreme wave conditions, fundamentally avoiding blade breakage and bearing damage caused by high-flow-rate airflow impacts in Wells turbines. Accelerated life testing has verified that the average service life of the turbine is extended from 3 years for a traditional single turbine to 8 years, reducing the annual maintenance cost of the device by more than 60%, and significantly lowering the total life-cycle cost of the ocean wave energy power generation device.

[0028] This invention maintains continuous and stable power output under calm, normal, and extreme sea conditions, with a power supply reliability exceeding 95%, completely solving the problem of easy shutdown and power outages of traditional single turbine buoys in rough seas. It can provide uninterrupted green power supply for offshore scenarios such as islands, offshore platforms, marine observation stations, and underwater sensor networks, significantly improving the independence and stability of offshore energy systems.

[0029] This invention employs a switching mechanism that uses a motor-driven threaded screw to slide the deflector. It features a simple structure, smooth transmission, and high positioning accuracy, with a single switching action completed within 1 second and minimal energy loss. All moving parts are sealed inside an air chamber, completely isolated from seawater, making them less susceptible to marine corrosion and marine organism adhesion. This allows for continuous operation for over 5 years without major oversight in harsh marine environments characterized by high salt spray, high humidity, and strong impacts. Furthermore, the modular design allows for independent disassembly and replacement of each component, facilitating installation and maintenance, and making it suitable for large-scale engineering applications.

[0030] The switching device of this invention can be directly adapted to most existing back-curved oscillating water column wave energy generating buoys without requiring large-scale modifications to the main structure of the buoy. The modification cost is only about 20% of that of a newly built buoy, making it highly valuable for widespread application. The threshold frequency and detection time interval can be flexibly adjusted according to the wave characteristics of different sea areas, adapting to the wave resource conditions of different sea areas.

[0031] In summary, this invention effectively solves the core problems of low power generation efficiency, poor applicability, and short lifespan of existing wave energy power buoys, and provides an efficient, reliable, and low-cost technical solution for the large-scale development and utilization of ocean wave energy, with broad market application prospects and significant economic, social, and environmental benefits. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of a backward-curved wave energy power generation buoy and its air turbine switching device according to the present invention.

[0033] Figure 2 This is a partial schematic diagram of the internal structure of the present invention;

[0034] Figure 3 This is a partial schematic diagram of the installation position of the wave frequency sensor and the wave ring of the present invention;

[0035] Figure 4 This is a partial schematic diagram of the flow guide shield movement structure of the present invention;

[0036] Figure 5 This is a schematic diagram of the process of switching air turbines according to different wave frequencies according to the present invention;

[0037] Among them: 1. L-shaped duct, 2. air chamber, 3. Wells turbine, 4. impact turbine, 5. inlet shroud, 6. flexible hose, 7. flow guide, 8. isolation shroud, 9. threaded screw, 10. motor, 11. frequency sensor, 12. mooring ring, 13. coupling. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] like Figure 1As shown, the backward-curved tube wave energy generating buoy and its air turbine switching device provided by this invention adopt a backward-curved tube oscillating water column structure, mainly composed of an L-shaped duct 1, an air chamber 2, a Wells turbine 3, an impingement turbine 4, an inlet shroud 5, a flexible hose 6, a flow guide shroud 7, an isolation shroud 8, a threaded screw 9, a motor 10, a wave frequency sensor 11, a mooring ring 12, a coupling 13, an internal processing unit, and a generator. The core innovation of this invention lies in addressing the shortcomings of a single turbine, which can only adapt to a specific wave frequency, has low power generation efficiency, and poor overload capacity. It involves paralleling the Wells turbine 3 and the impingement turbine 4, which have complementary performance, at the end of the same backward-curved tube air path. A sliding flow guide switching mechanism driven by wave frequency feedback automatically switches between the two turbines according to the real-time wave frequency, comprehensively leveraging the advantages of the Wells turbine's low-flow-rate high efficiency and the impingement turbine's high-flow-rate overload resistance. This significantly improves the buoy's wide-condition power generation efficiency and operational reliability, while also significantly extending the turbine's service life.

[0040] The L-shaped guide tube 1 is the main load-bearing structure of the buoy and also serves as the flow channel for the oscillating water column. It is formed by integrally molding horizontal and vertical pipe sections or connecting them through sealing flanges, and the whole is in a standard L shape. The L-shaped guide tube 1 is made of high-strength metal material that is resistant to seawater corrosion. Its structural dimensions are optimized for hydrodynamics according to the wave characteristics of the target sea area to ensure that the natural frequency of the buoy's oscillation matches the local dominant wave frequency, so as to achieve the best wave energy capture effect. The internal channel of the L-shaped guide tube 1 is smooth and without protrusions to reduce resistance loss during the oscillation of the water column.

[0041] The gas chamber 2 is a sealed cavity structure, sealed and connected to the upper end of the L-shaped duct 1, together forming a gas-liquid two-phase channel for the backward-curved oscillating water column. The gas chamber 2 is divided into a vertical section and a horizontal section. The vertical section is coaxially connected to the vertical section of the L-shaped duct 1, while the horizontal section extends to the opposite side of the wave-facing direction, with two independent, identical circular air outlets at its end. The two air outlets are arranged side-by-side, with a center-to-center distance greater than the outlet diameter to avoid mutual airflow interference. The inner wall of the gas chamber 2 is smoothed to reduce airflow resistance and ensure that the high-pressure airflow generated inside the gas chamber can flow smoothly to the turbine inlet.

[0042] The frequency sensor 11 is the core detection component for achieving adaptive switching of the turbine, such as... Figure 3 As shown. This installation location allows for direct detection of the raw parameters of the incident waves, minimizing the impact of the buoy's own swaying motion, reflected waves, and wake on detection accuracy. The wave frequency sensor 11 can acquire key parameters such as wave frequency and amplitude in real time and transmit the acquired electrical signals to the internal processing unit for analysis. The wave frequency sensor 11 adopts a waterproof and sealed design, with a protection level that meets the requirements for long-term underwater operation. Its surface can be coated with an anti-biofouling coating to prevent marine organisms from adhering and affecting detection performance.

[0043] The inlet shroud 5 is located above the oscillating liquid surface of the water column inside the air chamber 2. The inlet shroud 5 adopts a tapering flared shape, which can evenly converge and guide the reciprocating airflow generated by the up-and-down oscillation of the water column inside the air chamber 2 to the subsequent air path, effectively reducing turbulence loss and local resistance loss, and improving the utilization rate of airflow energy. The edge of the inlet shroud 5 is sealed to the inner wall of the air chamber 2 to prevent airflow leakage from the gap between the inlet shroud and the air chamber wall.

[0044] The flexible hose 6 is a flexible air passage element connecting the inlet shroud 5 and the guide shroud 7. One end of it is sealed and securely connected to the upper outlet of the inlet shroud 5, and the other end is sealed and securely connected to the air inlet of the guide shroud 7. When the guide shroud 7 moves left and right, the flexible hose 6 has a certain degree of flexibility and can move accordingly, while maintaining the air passage's seal, ensuring that the high-pressure airflow generated in the air chamber 2 can be delivered to the guide shroud 7 without leakage. The flexible hose 6 is made of elastic material that is resistant to seawater corrosion, aging, and high and low temperatures. An internal reinforcing layer can be added to improve its pressure resistance, enabling it to withstand the maximum working pressure inside the air chamber 2.

[0045] The air deflector 7 is installed near the end of the horizontal air chamber 2, and its sliding direction is consistent with the direction of the line connecting the centers of the two air outlets, such as... Figure 4 As shown. The air guide shroud 7 is a cavity structure with an air inlet at one end and an air outlet on one side. The size of its air outlet is exactly the same as the size of the air outlet at the end of the air chamber 2. The lower end of the air guide shroud 7 is connected to a threaded screw 9, which facilitates the left and right movement of the air guide shroud 7 to select the corresponding air outlet. When the threaded screw 9 rotates, it can drive the air guide shroud 7 to slide left and right along the axis of the threaded screw 9, so that the air outlet of the air guide shroud 7 is completely aligned with the air outlet corresponding to the Wells turbine 3 or the air outlet corresponding to the impact turbine 4, thereby guiding all the airflow in the air chamber 2 to the selected turbine and achieving seamless switching of the airflow path. A sealing element is provided between the outer wall of the air guide shroud 7 and the inner wall of the air chamber 2, which not only ensures that the air guide shroud 7 can slide smoothly, but also effectively prevents airflow from leaking from the gap between the air guide shroud and the air chamber wall.

[0046] The isolation cover 8 is installed inside the end of the rear bend and aligned with the two air outlets. The isolation cover 8 is a vertically arranged partition structure, its height equal to the height of the air outlets, and its width greater than the center-to-center distance between the two air outlets, effectively physically separating the airflow channels between the two outlets. The function of the isolation cover 8 is to prevent airflow from flowing from one air outlet to another non-operating turbine during or after switching, ensuring that all airflow enters the currently selected operating turbine and avoiding energy loss. The edge of the isolation cover 8 is sealed to the inner wall and end wall of the air chamber 2 to guarantee the separation effect.

[0047] The threaded screw 9 is horizontally arranged along the line connecting the centers of the two air outlets, and its two ends are rotatably mounted on the left and right inner walls of the air chamber 2 via bearing seats. The threaded screw 9 is made of high-strength, wear-resistant metal material, and its surface can be treated with anti-corrosion coating to adapt to the humid and high-salt spray working environment of the ocean. The motor 10 is connected and fixed to the threaded screw 9 via a coupling 13. One end of the threaded screw 9 extends out of the outer wall of the air chamber 2 and is coaxially fixedly connected to the output shaft of the motor 10 via the coupling 13.

[0048] Coupling 13 is used to connect the output shaft of motor 10 to threaded screw 9, transmitting the rotational torque of motor 10. Coupling 13 is preferably a flexible coupling, which can compensate for the coaxiality error and angular error between the output shaft of motor 10 and threaded screw 9, reduce vibration and noise during transmission, and improve the stability and service life of the transmission system.

[0049] Motor 10 is the power source driving the movement of the fairing 7. It is fixedly installed on the outer wall of the air chamber 2 and uses a waterproof, sealed motor with a protection level that meets the requirements for long-term operation in marine environments. Motor 10 is electrically connected to the internal processing unit and receives control signals from the internal processing unit to realize forward, reverse, and stop control, thereby driving the fairing 7 to slide left and right through the threaded screw 9. By precisely controlling the speed and number of rotations of motor 10, the sliding position and sliding speed of the fairing 7 can be precisely controlled, ensuring that the switching process is completed within 1 second and reducing energy loss.

[0050] At the two air outlets at the end of the backward-curved pipe, a Wells turbine 3 and an impulse turbine 4 are installed respectively, with the air inlets of both facing the interior of air chamber 2 and sealed to the end wall of air chamber 2 via flanges. The Wells turbine 3 is a self-rectifying turbine with symmetrical airfoil blades that can maintain unidirectional rotation under reciprocating airflow without the need for additional rectification devices, exhibiting high energy conversion efficiency under medium-low flow velocity and medium-high frequency wave conditions. The impulse turbine 4 generates rotational torque by airflow impacting the blades, exhibiting high energy conversion efficiency under high flow velocity, low-frequency, large-amplitude wave conditions, and possessing strong overload capacity, able to withstand significant airflow impact without easily being damaged. The output shafts of the two turbines are respectively connected to corresponding generators, converting the turbine's rotational mechanical energy into electrical energy output.

[0051] The mooring ring 12 is fixedly installed at the bottom of the L-shaped guide tube 1 for mooring and positioning of the buoy. Using high-strength mooring lines and the mooring ring 12, the buoy can be moored at designated locations such as ships, coastlines, islands, reefs, and offshore platforms, preventing it from being washed away by waves. The mooring ring 12 is forged from high-strength metal materials, possessing sufficient tensile strength to withstand the enormous pulling forces of ocean waves.

[0052] The internal processing unit is the control core of the entire switching device, integrating signal acquisition, data processing, logic judgment, and motor drive functions. Electrically connected to the wave frequency sensor 11 and the motor 10, the internal processing unit receives wave parameter signals collected by the wave frequency sensor 11, analyzes and judges them according to preset control logic, and sends corresponding control commands to the motor 10 to drive the fairing 7 to complete the turbine switching action. The internal processing unit is waterproof and sealed, installed in the dry compartment of the buoy, ensuring long-term reliable operation in the marine environment.

[0053] The generator is connected to the output shafts of Wells Turbine 3 and Impulse Turbine 4 respectively, converting the rotational mechanical energy of the turbines into electrical energy. After rectification and voltage stabilization, the electrical energy output by the generator can be directly used to power offshore loads such as islands, offshore platforms, and marine observation stations, or it can be stored in batteries for use when wave energy is insufficient.

[0054] Working principle of the device:

[0055] The basic working principle of the wave energy generating buoy of the present invention is based on the wave energy conversion principle of oscillating water column. When the wave acts on the buoy from the wave-facing direction, the wave pushes the floating back bend to make a rocking motion, which causes the water column in the L-shaped duct 1 and the air chamber 2 to oscillate violently in the air chamber, generating a reciprocating high-pressure airflow to drive the turbine to rotate, and finally outputting electrical energy by the generator.

[0056] The air turbine switching device operates on a closed-loop control principle based on wave frequency feedback. The wave frequency sensor 11 monitors the current wave frequency in real time, compares it with a set frequency threshold through an internal processing unit, and then controls the motor 10 to drive the lead screw 9 to control the guide shroud 7 to select the appropriate air turbine. Every preset time interval T, the internal processing unit re-acquires wave parameters and repeats the above judgment and switching process, achieving adaptive cyclic switching of the turbine.

[0057] Detailed implementation steps of the air turbine switching method:

[0058] The air turbine switching method of the present invention is automatically executed by an internal processing unit, and the specific steps are as follows:

[0059] (1) Set the threshold frequency as f(x) and the time interval T;

[0060] ① Criteria for comparing turbine efficiency

[0061] ;

[0062] in, : Energy conversion efficiency of Wells Turbine 3, dimensionless; Energy conversion efficiency of the impact turbine 4, dimensionless; : The frequency of the incident wave, measured in Hertz (Hz); Wave height of the incident wave, measured in meters (m).

[0063] This criterion forms the theoretical basis for turbine switching, indicating that when the energy conversion efficiencies of two turbines are equal at the same wave frequency and wave height, the corresponding wave parameters are the theoretical switching critical point.

[0064] ② Frequency coefficient switching threshold

[0065] ;

[0066] in, Frequency coefficient, dimensionless, used to quantify the degree of matching between wave conditions and turbine characteristics; The frequency of the incident wave, measured in Hertz (Hz). The water surface area of ​​air chamber 2, in square meters (m²) 2 ); : The oscillation amplitude of the water surface inside air chamber 2, in meters (m); The cross-sectional area of ​​the turbine's air inlet, expressed in square meters (m²). 2 ); The circumferential velocity of the turbine blade, measured in meters per second (m / s). Switching threshold setting: Experimentally verified, the set frequency coefficient threshold is [value missing]. .when At that time, Wells Turbine 3 was highly efficient; when At that time, the shock turbine 4 is highly efficient. The threshold frequency of this embodiment is calculated using this formula. Hz.

[0067] ③Total efficiency of dual turbines

[0068] ;

[0069] in, The overall energy conversion efficiency of the device is dimensionless. Energy conversion efficiency of chamber 2, dimensionless; The energy conversion efficiency of a generator is dimensionless.

[0070] ④ Device output power

[0071] ;

[0072] in, The output power of the device is expressed in kilowatts (kW). The overall coefficient corresponding to Wells Turbine 3 is dimensionless. : The comprehensive coefficient corresponding to the impact turbine 4, dimensionless.

[0073] In this step, the detection time interval is also set. This time interval can respond promptly to changes in wave conditions without switching too frequently, effectively extending the service life of motor 10 and transmission mechanism.

[0074] (2) Set the upper limit of the effective frequency when the power generation device is working normally. Lower limit ;

[0075] Based on the normal operating frequency range of the two turbines, an effective frequency lower limit is set. upper limit of effective frequency It covers the frequency range of most ocean waves.

[0076] (3) Monitor the frequency of the current wave using a wave frequency sensor. ;

[0077] The frequency of the incident wave is monitored in real time by a wave frequency sensor 11 installed in the middle of the horizontal pipe of the L-shaped duct 1, facing the direction of the incoming wave. Simultaneously, the amplitude of the waves was collected. Parameters. Frequency sensor 11 with... The sampling frequency is used to ensure accurate capture of the instantaneous changes in the waves. The acquired raw signal is first amplified, low-pass filtered, and converted from analog to digital by the signal processing circuit to remove noise and interference, and then transmitted to the internal processing unit for further processing and analysis.

[0078] (4) Detect the current wave frequency If the frequency is outside the specified effective frequency range, the system defaults to selecting shock turbine 4; if it is within the specified effective frequency range, the system compares the wave frequency at this time. With threshold frequency ;

[0079] If the current wave frequency or This indicates that the wave condition exceeds the normal operating range of the device. Under this condition, Wells turbine 3 is highly susceptible to overload damage, while the impulse turbine 4 has a strong overload capacity and can withstand the impact of large-volume airflow under extreme conditions. Therefore, the system defaults to selecting impulse turbine 4. The internal processing unit sends control commands to motor 10, driving motor 10 to rotate the threaded screw 9, which in turn drives the guide shroud 7 to slide to the corresponding air outlet position of impulse turbine 4, allowing all the airflow generated in air chamber 2 to enter impulse turbine 4, which then drives the generator to generate electricity.

[0080] if This indicates that the current wave conditions are within the normal operating range of the device. The internal processing unit then further compares the wave frequency at this time. With threshold frequency Size.

[0081] (5) If the frequency is greater than the threshold frequency, the motor-driven flow guide should use an impact turbine 4; if the frequency is less than the threshold frequency, the motor-driven flow guide should use a Wells turbine 3.

[0082] The above judgment can be further refined as follows:

[0083] When the wave frequency sensor 11 detects a wave frequency of 0.5~1.5Hz, an amplitude of 0.3~1.0m, and an airflow rate of 5~15m³ / h... 3 When the flow rate is / s, it is determined to be a medium-low flow, medium-high frequency wave condition. At this time, Wells Turbine 3 is in a high-efficiency operating state (efficiency ≥45%). The controller controls the switching of the flow guide 7 to maintain the current state and continue to use Wells Turbine 3 to generate electricity.

[0084] When the wave frequency sensor 11 detects a wave frequency ≤ 0.5Hz, amplitude ≥ 1.0m, and flow rate ≥ 15m³, 3 When the flow rate is / s, it is determined to be a high-flow, low-frequency, large-amplitude wave condition. At this time, the efficiency of Wells turbine 3 decreases (efficiency <35%), while the impulse turbine 4 is more suitable for this condition. The controller immediately issues a switching command to control motor 10 to drive the flow guide 7 to move. The switching process is completed within 1 second, reducing energy loss.

[0085] After the switching is completed, the reciprocating airflow enters the impulse turbine 4, and the airflow direction is guided by the fixed guide vanes, which pushes the rotor of the impulse turbine 4 to rotate in one direction, driving the generator to continue generating electricity. At this time, the efficiency of the impulse turbine 4 is ≥40%, which is significantly higher than the efficiency of the Wells turbine 3 under the same operating conditions.

[0086] When the wave conditions change again, returning to low-to-medium flow and medium-to-high frequency conditions, the controller detects the parameter changes through sensors and automatically issues a switching command to switch the turbine back to Wells Turbine 3, achieving cyclic adaptive switching.

[0087] (6) Detect the wave frequency at intervals T every time, and repeat steps (3) to (5).

[0088] Every preset time interval The internal processing unit will then re-detect the current wave frequency using the wave frequency sensor 11. With amplitude Repeat steps (3) to (5) to continuously monitor changes in wave conditions, adjust the working turbine in real time, and ensure that the device always operates at the highest efficiency.

[0089] Specific switching implementation example:

[0090] To more clearly illustrate the switching method of the present invention, two typical switching embodiments are given:

[0091] Example 1: Switching between low-to-medium flow and high-frequency operating conditions

[0092] During a routine summer submersion in a certain sea area of ​​the Yellow Sea in my country, wave frequency sensor 11 detected the current wave frequency. ,amplitude airflow rate in chamber 2 The internal processing unit first determines... Within the preset effective frequency range Inside. Then compare. With threshold frequency By combining wave height and airflow parameters, it was found that the operating condition is a medium-low flow, medium-high frequency wave condition, and Wells Turbine 3 is more efficient.

[0093] The internal processing unit sends control commands to the motor 10. If the current air guide 7 is not in the position corresponding to the Wells turbine 3, the motor 10 drives the screw 9 to rotate, driving the air guide 7 to slide to the air outlet position corresponding to the Wells turbine 3. The switching action is completed within 0.8 seconds. After the switching is completed, all the reciprocating airflow generated by the air chamber 2 enters the Wells turbine 3, driving the Wells turbine 3 to rotate at a speed of 2800 r / min, thereby driving the generator to generate electricity. At this time, the efficiency of the Wells turbine 3 can reach 46%, the generator output power is 2.2kW, and the device outputs stable electrical energy.

[0094] Example 2: Switching between high flow rate, low frequency, and large amplitude operating conditions

[0095] During the winter typhoon season, wave frequency sensor 11 detects the current wave frequency in this sea area. Hz, amplitude m, airflow rate inside chamber 2 s. The internal processing unit first determines The Hz frequency is within the preset effective frequency range [0.1Hz, 2.0Hz]. Then compare... With threshold frequency Since 0.3Hz < 0.5Hz, and the amplitude is ≥ 1.0m and the airflow rate is ≥ 15m³ / h, the required values ​​are Hz. Under the condition of 's', the internal processing unit determines that the current operating condition is a high-flow, low-frequency, large-amplitude wave condition. The impingement turbine 4 is more efficient, and the Wells turbine 3 faces a serious overload risk. The internal processing unit immediately issues a switching command, controlling motor 10 to drive the threaded screw 9 to rotate rapidly, driving the guide shroud 7 to slide to the corresponding air outlet position of the impingement turbine 4 within 0.7s. After the switching is completed, the high-pressure reciprocating airflow generated by air chamber 2 all enters the impingement turbine 4. The fixed guide vanes of the impingement turbine 4 guide the airflow direction, driving the rotor to rotate at a speed of 1400r / min, driving the generator to generate electricity. At this time, the efficiency of the impingement turbine 4 can reach 42%, and the generator output power is 3.5kW, significantly higher than the efficiency of the Wells turbine 3 under the same operating conditions. Simultaneously, it effectively protects the Wells turbine 3 from damage caused by the impact of the high-flow airflow. After the typhoon, the wave condition gradually returns to normal. The wave frequency sensor 11 detects that the wave frequency has risen back to 0.7Hz, the amplitude has dropped to 0.5m, and the airflow rate has dropped to 8m³ / s. 3 When the airflow deflector 7 is switched back to the air outlet corresponding to Wells Turbine 3, the internal processing unit automatically issues a switching command to restore the efficient operation of Wells Turbine 3.

[0096] This invention addresses the shortcomings of existing pneumatic wave energy generating buoys, which mostly use a single turbine, can only adapt to specific wave frequencies, resulting in low power generation efficiency, poor applicability, and high environmental requirements. It provides a backward-curved tube wave energy generating buoy and its air turbine switching device and method. This invention can switch between a Wells turbine and an impulse turbine based on the wave frequency, combining the advantages of both turbines to improve power generation efficiency and effectively increase the turbine's service life.

[0097] This invention features a simple structure, convenient control, and reliable operation. It can adapt to wave conditions in different sea areas and seasons, providing a more stable and efficient power supply for offshore scenarios such as islands, offshore platforms, and marine observation stations, and has broad application prospects.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wave energy generating buoy with a curved tube, characterized in that, The device includes an air turbine switching device and a generator that is connected to a Wells turbine (3) and an impulse turbine (4) respectively. The air turbine switching device includes an L-shaped duct (1), an air chamber (2), and an air turbine. The L-shaped duct (1) and the air chamber (2) are connected to form a backward bend. An oscillating water column channel is formed inside the backward bend. The air turbine includes a Wells turbine (3) and an impulse turbine (4). The device also includes an inlet shroud (5), a flexible hose (6), a sliding guide shroud (7), an isolation shroud (8), a threaded screw (9), a drive motor (10), a frequency sensor (11), and a control unit. The end of the backward bend is provided with two independent air outlets. The Wells turbine (3) and the impulse turbine (4) are respectively installed at the two air outlets. The inlet shroud (5) The air inlet end is fixed to the air chamber (2), the slidable guide hood (7) is slidably disposed at the air outlet end of the air chamber (2), and the inlet hood (5) and the slidable guide hood (7) are sealed and connected by a flexible hose (6); the isolation hood (8) is fixed to the inner side of the end of the back bend and aligned with the two air outlets, and is used to separate the airflow channels of the two air outlets; the drive motor (10) is connected to the slidable guide hood (7) through the threaded screw (9), and is used to drive the slidable guide hood (7) to slide back and forth between the two air outlets to switch the airflow path; the wave frequency sensor (11) is installed in the L-shaped duct (1), and the wave frequency sensor (11) and the drive motor (10) are both electrically connected to the control unit, and the control unit controls the drive motor (10) to operate according to the wave frequency detected by the wave frequency sensor (11).

2. The wave energy generating buoy with a curved tube according to claim 1, characterized in that, The wave frequency sensor (11) is installed in the middle of the horizontal section of the L-shaped conduit (1), and the detection surface of the wave frequency sensor (11) faces the wave direction.

3. The wave energy generating buoy with a curved tube according to claim 1, characterized in that, The inlet shroud (5) is fixed to the upper part of the vertical pipe section of the air chamber (2), and the slidable guide shroud (7) is slidably installed on the horizontal pipe section of the air chamber (2) near the end.

4. The wave energy generating buoy with a curved tube according to claim 1, characterized in that, The output shaft of the drive motor (10) is coaxially and fixedly connected to the threaded screw (9) via a coupling (13), and the lower end of the slidable guide shield (7) is threadedly connected to the threaded screw (9).

5. A wave energy generating buoy with a curved tube according to claim 1, characterized in that, At least one mooring ring (12) is fixedly provided at the bottom of the L-shaped guide tube (1) for mooring and positioning of the buoy.

6. A switching method for the air turbine switching device of the back-curved tube wave energy power generation buoy as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Preset threshold frequency f(x), detection time interval T, and effective frequency upper limit f1 and effective frequency lower limit f2 for normal operation of the power generation device; S2: Monitor the current wave frequency f(i) using the wave frequency sensor (11); S3: Determine whether the current wave frequency f(i) is within the effective frequency range of [f2, f1]; S4: If f(i) exceeds the range of [f2,f1], the control unit controls the drive motor (10) to drive the sliding guide shroud (7) to switch to the air outlet corresponding to the impact turbine (4); if f(i) is within the range of [f2,f1], compare the magnitude of f(i) with the threshold frequency f(x); S5: If f(i) > f(x), switch to the air outlet corresponding to the impact turbine (4); if f(i) < f(x), switch to the air outlet corresponding to the Wells turbine (3); S6: Repeat steps S2 to S5 at each time interval T.

7. The switching method according to claim 6, characterized in that, The threshold frequency f(x) in step S1 is determined based on the turbine efficiency comparison criterion, which is the intersection of the efficiency η_wells(f,H) of the Wells turbine (3) and the efficiency η_impulse(f,H) of the shock turbine (4), where f is the wave frequency and H is the wave height.

8. The switching method according to claim 6, characterized in that, In steps S3 to S5, when the wave frequency sensor (11) detects a wave frequency of 0.5~1.5Hz, an amplitude of 0.3~1.0m, and an airflow rate of 5~15m³ / h in the air chamber (2), 3 When the flow rate is / s, it is determined to be a medium-low flow rate medium-high frequency operating condition, and the control is maintained or switched to Wells turbine (3); when the wave frequency sensor (11) detects a wave frequency ≤0.5Hz, amplitude ≥1.0m and airflow rate of air chamber (2) ≥15m 3 When the flow rate is / s, it is determined to be a high flow rate, low frequency and large amplitude operating condition, and the control is maintained or switched to the impact turbine (4).

9. The switching method according to claim 6, characterized in that, In steps S4 and S5, the single switching action of the sliding fairing (7) is completed within 1 second; after the switching is completed, the reciprocating airflow generated by the air chamber (2) drives the generator to output electrical energy through the corresponding turbine.

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