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A novel floating pendulum wave energy converter (WEC) with the ability of tide adaptation is designed and presented in this paper. Aiming to a high efficiency, the buoy''s hydrodynamic shape is optimized by enumeration and comparison. Furthermore, in order to keep the buoy''s well-designed leading edge always facing the incoming wave straightly, a novel transmission mechanism is then adopted, which is called the tidal adaptation mechanism in this paper. Time domain numerical models of a floating pendulum WEC with or without tide adaptation mechanism are built to compare their performance on various water levels. When comparing these two WECs in terms of their average output based on the linear passive control strategy, the output power of WEC with the tide adaptation mechanism is much steadier with the change of the water level and always larger than that without the tide adaptation mechanism. 相似文献
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The present study proposed a floating multi-body wave energy converter composed of a floating central platform, multiple oscillating bodies and multiple actuating arms. The relative motions between the oscillating bodies and the floating central platform capture multi-point wave energy simultaneously. The converter was simplified as a forced vibration system with three degrees of freedom, namely two heave motions and one rotational motion. The expressions of the amplitude-frequency response and the wave energy capture width were deduced from the motion equations of the converter. Based on the built mathematical model, the effects of the PTO damping coefficient, the PTO elastic coefficient, the connection length between the oscillating body and central platform, and the total number of oscillating bodies on the performance of the wave energy converter were investigated. Numerical results indicate that the dynamical properties and the energy conversion efficiency are related not only to the incident wave circle frequency but also to the converter's physical parameters and interior PTO coefficients. By adjusting the connection length, higher wave energy absorption efficiencies can be obtained. More oscillating bodies installed result in more stable floating central platform and higher wave energy conversion efficiency. 相似文献
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Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method (AM) was used to separate the incident and reflected waves propagating in a wave flume by analysing wave records measured at two locations. The response amplitude operator (RAO), primary conversion efficiency and the total conversion efficiency of the wave energy converter were studied; furthermore, the power take-off damping coefficients corresponding to the load resistances in the experiment were also obtained. The findings demonstrate that the natural period for a pendulum wave energy converter is relatively large. A lower load resistance gives rise to a larger damping coefficient. The model shows relatively higher wave energy conversion efficiency in the range of 1.0?1.2 s for the incident wave period. The maximum primary conversion efficiency achieved was 55.5%, and the maximum overall conversion efficiency was 39.4%. 相似文献
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Ocean wave energy converters (WECs) are obtaining more and more attentions in the world. So far, many types of converters have been invented. Oscillating body systems are a major class of WECs, which typically have one degree of freedom (DOF), and the power absorption efficiency is not quite satisfactory. In this paper, a 3-DOF WEC is proposed and a simplified frequency-domain dynamic model of the WEC depending on the linear potential theory is conducted. The performances of three geometries of the oscillating body including the cone, the cylinder and the hemisphere have been compared, and the results show that the hemisphere is more suitable for the 3-DOF WEC. Subsequently, the relationship among the parameters of the hemisphere is established based on the equal natural frequencies of the heave and pitch (or roll) motions, and the results show that lowering the center of gravity leads to the better power absorption in the pitch (or roll) motion. In the end, the power matrixes of different sizes of the hemispheres under different irregular waves are obtained, which can give a size design reference for engineers. 相似文献
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浮子的能量收集效率对于装置发电效率的提升具有重要作用。针对传统浮子式装置仅具有一个自由度的问题,提出了一种新型六自由度波浪能装置。基于线性波理论和MMG(Ship Manoeuvring Mathematical Model Group)方法,建立了新型装置的水动力学模型。分析了此装置的浮子在线性波浪作用下的位移和速度。结果表明:新型六自由度装置可以同时收集浮子六自由度方向的动能,具有较高的波浪能收集效率。另外,浮子在垂荡方向上的动能远大于横荡、纵荡方向上的动能。分析了波浪能收集效率随波浪遭遇角与弹簧系数之间的变化规律,文中工作为新型波浪能装置的优化设计提供了有益参考。 相似文献
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《中国海洋工程》2021,(4)
In the present study, the performance characteristics of a Savonius rotor type wave energy converter used in conjunction with a conventional double-buoy floating breakwater is investigated using physical model studies. The Savonius rotor type converter is suspended under the double-buoy floating breakwater to achieve wave attenuation while generating electricity, thereby enhancing the overall wave-elimination effect of the combination. The Savonius rotor is tested with different water submergence depths, and a reasonable relative submergence depth is determined within the scope of the research parameters. The hydrodynamics and energy capture performance of the combined breakwater with four different sizes of Savonius rotor under different wave conditions are studied, and the transmission coefficient of the experimental device is analyzed. The results show that when the optimal relative submergence depth is 0.65 D, where D is the impeller diameter, there is a correspondence between the optimal performance of Savonius rotor with different rotor sizes and the wave period and wave height. The optimal energy capture efficiency of the wave energy converter reaches 17%-20.5%, and the transmission coefficient is reduced by35%-45% compared with the conventional double-buoy breakwater. 相似文献
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摆式波能装置具有结构简单和转化效率高等特点,本文应用AQWA 软件基于势流理论对相交圆柱摆式波能装置进行了数值模拟研究,分析了轴间距比、结构阻尼、净浮力比、水深、波浪特性及吃水深度等主要参数对相交圆柱摆式波能装置俘获效率的影响,并与直板摆式波能装置的俘获效率进行了对比。结果表明:同样条件下,相交圆柱摆式波能装置往往比直板摆式波能装置的俘获效率更高;在研究范围内,轴间距比越大俘获效率越高;潮汐导致的水深变化对底铰摆式波能装置的俘获效率具有明显的影响,在工程应用中应采取适当的措施进行处理。 相似文献
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Wave tank tests were carried out to evaluate the total efficiency of a floating OWC Pentagonal Backward Bent Duct Buoy (PBBDB). Two kinds of turbine generators were used in tests. The incident wave power, pneumatic power and electricity were measured. The test results show that the primary efficiency can reach up to 185.98% in regular waves and 85.86% in irregular waves. The total efficiency from wave to wire with Wells turbine-generator set is 33.43% in regular waves and 15.82% in irregular waves. The peak total efficiency of the PBBDB with check valves equipped with the impulse turbine-generator set is 41.68% in regular waves and 27.10% in irregular waves. The efficiency of the turbine-generator set is about 30% in the tests. Obviously, the total efficiency can be further improved with the increasing of turbine efficiency. 相似文献
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《海洋技术学报》2023,(2)
主动共振浮力摆式波浪能发电装置通过调节内部配重位置实现共振发电。本文以基于机械式动力输出系统(Power Take-off, PTO) 的主动共振浮力摆式波浪能发电装置为研究对象,构建波-电时域动力学模型并验证模型可行性, 该模型的非线性特征主要体现在正弦函数形式的静水回复力矩及止动力矩中。进一步, 研究自振周期同不规则波能量周期一致的共振状态下,不同负载形式及取值大小对装置时域响应曲线、时均功率和效率的影响。研究结果表明: 不同负载设置对俘获宽度比的影响大于PTO 传动效率。阻性负载值过大或过小均会削弱俘获宽度比, 使有功时均值和发电效率下降, 共振状态下, 负载的感性或容性成分会使发电机产生大量无功, 且无功有正有负, 感性或容性成分能有效削弱俘获宽度比、有功时均值和发电效率。 相似文献
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The double-body heave wave energy converter(WEC) is one of the most conducive devices to absorb the wave energy from relative motion while the law of which is not well understood. This paper makes an in-depth study on this wave energy converter, by means of the combination of theoretical analysis and physical model experiment. The hydrodynamic characteristics and energy capture of the double-buoy under constant and linear Power Take-Off(PTO) damping are investigated. Influences of absolute mass and mass ratio are discussed in the theoretical model.Relative displacement amplitude and average power output are tested in the experiment to analyze the effect of the wave period and outer buoy's mass, while the capture width ratio(CWR) is also calculated. Results show that the wave period and mass of the buoys have a significant effect on the converter. Different forms of PTO damping have no influence on the optimal wave period and mass ratio of this device. It is recommended to select the double-buoy converter with a mass ratio of 0.80 and to place it in an area with the frequent wave period close to the natural period of the outer buoy to achieve the optimal energy capture. 相似文献
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Among the wave energy converters (WECs), oscillating buoy is a promising type for wave energy development in offshore area. Conventional single-freedom oscillating buoy WECs with linear power take-off (PTO) system are less efficient under off-resonance conditions and have a narrow power capture bandwidth. Thus, a multi-freedom WEC with a nonlinear PTO system is proposed. This study examines a multi-freedom WEC with 3 degrees of freedom: surge, heave and pitch. Three different PTO systems (velocity-square, snap through, and constant PTO systems) and a traditional linear PTO system are applied to the WEC. A time-domain model is established using linear potential theory and Cummins equation. The kinematic equation is numerically calculated with the fourth-order Runge–Kutta method. The optimal average output power of the PTO systems in all degrees of freedom are obtained and compared. Other parameters of snap through PTO are also discussed in detail. Results show that according to the power capture performance, the order of the PTO systems from the best to worst is snap through PTO, constant PTO, linear PTO and velocity-square PTO. The resonant frequency of the WEC can be adjusted to the incident wave frequency by choosing specific parameters of the snap through PTO. Adding more DOFs can make the WEC get a better power performance in more wave frequencies. Both the above two methods can raise the WEC’s power capture performance significantly. 相似文献
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《中国海洋工程》2020,(4)
This paper presents an oscillating slider wave energy device which is based on a seabed anchoring and uses eagle beak as the absorber. The self-compiled program uses the boundary element theory based on the simple Green's function to solve the wave forces and hydrodynamic parameters. And the equation of motion, the oscillation of the float and the capture width ratio are obtained by the modal method. The influences of the shape of the eagle beak, the angle of the slider and the wave heading on the capture ability of the device are investigated. According to the calculation results and the wave resources in the sea area, the optimal shape of the eagle beak and external damping can be selected to maximize the wave energy capture capability. 相似文献
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As an important wave energy converter(WEC),the double-buoy device has advantages of wider energy absorption band and deeper water adaptability,which attract an increasing number of attentions from researchers.This paper makes an in-depth study on double-buoy WEC,by means of the combination of model experiment and numerical simulation.The Response Amplitude Operator(RAO) and energy capture of the double-buoy under constant power take-off(PTO) damping are investigated in the model test,while the a... 相似文献
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According to Newton''s Second Law and the microwave theory, mechanical analysis of multiple buoys which form Sharp Eagle wave energy converter (WEC) is carried out. The movements of every buoy in three modes couple each other when they are affected with incident waves. Based on the above, mechanical models of the WEC are established, which are concerned with fluid forces, damping forces, hinge forces, and so on. Hydrodynamic parameters of one buoy are obtained by taking the other moving buoy as boundary conditions. Then, by taking those hydrodynamic parameters into the mechanical models, the optimum external damping and optimal capture width ratio are calculated out. Under the condition of the optimum external damping, a plenty of data are obtained, such as the displacements amplitude of each buoy in three modes (sway, heave, pitch), damping forces, hinge forces, and speed of the hydraulic cylinder. Research results provide theoretical references and basis for Sharp Eagle WECs in the design and manufacture. 相似文献
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China Ocean Engineering - Edinburgh Duck wave energy converter (ED WEC) has excellent energy extraction performance and shows a great potential to integrate with other marine structures. This paper... 相似文献
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Experimental Investigation on the Hydrodynamic Performance of A Wave Energy Converter 总被引:1,自引:0,他引:1
Wave energy is an important type of marine renewable energy. A wave energy converter (WEC) moored with two floating bodies was developed in the present study. To analyze the dynamic performance of the WEC, an experimental device was designed and tested in a tank. The experiment focused on the factors which impact the motion and energy conversion performance of the WEC. Dynamic performance was evaluated by the relative displacements and velocities of the oscillator and carrier which served as the floating bodies of WEC. Four factors were tested, i.e. wave height, wave period, power take-off (PTO) damping, and mass ratio (RM) of the oscillator and carrier. Experimental results show that these factors greatly affect the energy conversion performance, especially when the wave period matches RM and PTO damping. According to the results, we conclude that: (a) the maximization of the relative displacements and velocities leads to the maximization of the energy conversion efficiency; (b) the larger the wave height, the higher the energy conversion efficiency will be; (c) the relationships of energy conversion efficiency with wave period, PTO damping, and RM are nonlinear, but the maximum efficiency is obtained when these three factors are optimally matched. Experimental results demonstrated that the energy conversion efficiency reached the peak at 28.62% when the wave height was 120 mm, wave period was 1.0 s, RM was 0.21, and the PTO damping was corresponding to the resistance of 100 Ω. 相似文献
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Flávio Medeiros SEIBT Eduardo Costa COUTO Elizaldo Domingues dos SANTOS Liércio André ISOLDI Luiz Alberto Oliveira ROCHA Paulo Roberto de Freitas TEIXEIRA 《海洋工程》2014,28(5):687-700
The growing search for clean and renewable energy sources has given rise to the studies of exploring sea wave energy. This paper is concerned with the numerical evaluation of the main operational principle of a submerged plate employed for the conversion of wave energy into electrical one. The numerical model used to solve the conservation equations of mass, momentum and transport of volume fraction is based on the finite volume method (FVM). In order to tackle with the flow of mixture of air-water and its interaction with the device, the multiphase model volume of fluid (VOF) is employed. The purpose of this study is the evaluation of a numerical model for improvement of the knowledge about the submerged plate wave energy converter, as well as the investigation of the effect of the distance from the plate to the bottom of the sea (HP) on the performance of the converter. The simulations for several distances of the plate from the seabed show that the optimal efficiency is 64%, which is obtained for HP=0.53 m (88% of the depth). This efficiency is 17% larger than that found in the worst case (HP=0.46 m, 77% of the depth). 相似文献