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1.
振荡水柱式(Oscillation Water Column,简称OWC)波浪能采集装置具有结构简单、稳定性好、海洋环境适应性强等优点。为了提高该装置波能采集效率,研究波浪进入气室的振荡水柱气动特性与装置结构参数关系,为系统设计提供理论基础。以振荡水柱式波能转换理论计算分析为基础,采用Simulink软件分别建立前墙处入口压强Pq求解模型、装置气室内压强Po求解模型以及装置内振荡水柱运动方程y求解模型,研究目的是综合分析振荡水柱气室内压强与气室结构、波浪流体动力学参数之间的变化关系。 相似文献
2.
采用计算流体动力学分析(CFD)技术研究离岸式振荡水柱波能转换装置的设计参数优化问题。首先,借助FLUENT软件用户自定义函数功能(UDF)并运用动边界造波及多孔介质消波方法建立基于线性波浪理论的二维数值波浪水槽,然后,将水槽的分析方法应用于振荡水柱气室仿真研究。结果表明:离岸式振荡水柱气室在发生共振时转换效率最高,气室内液面升降幅度随着波能转换装置的前墙入水深度、厚度以及气室宽度的减小而产生较明显的增大;相对于前墙尺寸,气室宽度对波能转换装置的能量转换功率影响较大。 相似文献
3.
基于VOF模型的OWC气室波浪场数值分析 总被引：1，自引：0，他引：1
近年来,振荡水柱形式在波能转换装置中得到了广泛应用,由于波况不同,需对气室加以研究并对其形状参量进行优化,从而使空气流速和能量转换达到最大值.利用基于VOF模型建立二维数值波浪水槽,将数值计算的振荡水柱在气室内的升沉运动与物理模型试验进行比较,验证其正确性,并将OWC气室的研究手段予以推广. 相似文献
4.
振荡水柱(Oscillating water column,OWC)波浪能采集装置气室底部引浪通道对波浪能采集效率具有重要意义。基于流体动力学分析(CFD)技术研究OWC装置气室底部轮廓的优化问题,在ICEM CFD仿真分析系统中建立4种气室底部结构的二维引浪通道模型,应用FLUENT软件流体分相处理及明渠造波法和数值沙滩消波方法建立基于线性波浪理论的二维数值波浪水槽。仿真分析显示,圆形底部轮廓OWC气室较其它3种轮廓结构的气室墙壁受到压力小,形成的反射波小,波能损失小,气室出口速度快由此形成的气室压力大,波能转换效率高。 相似文献
5.
为了解决振动水柱式波浪能转换装置收集多向波浪问题,本文设计了半球形多向聚合波道振荡水柱气室结构,以适合远海单点波浪能采集和发电。在规则波正向入射条件下,基于流体仿真分析软件(FLUENT)、流体动力学连续性假设和粘性不可压缩流体动量守恒的运动方程(Navier-Stokes方程)建立半球形振荡气室和三维数值波浪水槽模型。仿真结果表明:增设气室后壁,合理设计波道开口角度实现多向迎波捕获波浪能,优化前壁形状可降低波浪触底反射带来的能量耗散,同时提高了气室内空气压强和出气口速度,有效提升波浪能俘获效率,为后续发电的二次能量转换提供高效的空气动力。 相似文献
6.
为实现建造、运行和维护等方面的资源共享,将振荡水柱(oscillating water column,简称OWC)波能转换装置与现有海工结构集成耦合,已成为目前海洋波浪能转换利用的热点问题。以集成于方箱防波堤的双气室OWC装置为研究对象,借助开源代码平台OpenFOAM和造/消波工具箱waves2Foam,采用流体体积法(VOF)捕捉自由面和6自由度(6DOF)动网格求解器模拟垂荡运动响应,对在不同规则波作用下,中墙相对宽度、中墙相对吃水对装置波能转换效率及水动力特性的影响进行数值研究。结果表明,较大的中墙相对宽度能够增强装置的波能转换效率(ξtotal(max)=73%)、降低结构物的相对垂荡位移并对装置前后气室内水柱的振荡幅度与压强变化产生影响;增加中墙相对吃水能显著提高气室在中高频波段波能提取效率(ξtotal(max)=78%),并显著拓宽气室的高效频率带宽(0.9≤ω2h/g≤2.2)。 相似文献
7.
振荡水柱波能转换装置的最大转换效率往往受到腔内水柱共振机制的直接影响。通过对装置的基本结构进行简化,提出了一种前墙可绕固定轴旋转的双垂板式结构系统,旨在通过前墙的旋转运动进一步加剧水柱的振荡,从而对腔内水柱的共振机制进行调节和控制。基于线性波理论,采用匹配特征函数展开法对波浪与双垂板结构的相互作用进行理论研究,针对流场在结构物尖角附近的奇异性特征,将公共界面上的速度分布基于切比雪夫多项式近似展开,并应用区域间的速度与压力连续条件进行求解。通过分析结构的几何参数对反射透射系数、平均波面高程、前墙旋转振幅以及前墙与水面间相位差的影响,深究其共振机理,为振荡水柱波能转换装置的效率优化机制提供理论依据。结果表明,在所研究的波浪频率范围内,前墙的自由旋转运动会加剧板间的平均波面高程,应用于波浪能转换装置中能进一步拓宽高效频率带宽。 相似文献
8.
9.
《中国海洋大学学报(自然科学版)》2017,(7)
振荡水柱式波能发电系统中波能转换主要结构气室能将入射波能转换为往复振荡的空气动能从而实现能量一次转换,该过程的气室压强研究对发电系统设计具有重要意义。因此针对"引浪板"和"引浪通道"的三维侧向开口固定式振荡水柱波能转换系统,采用三维Green函数法建立了气室内水气动力学性能的压缩空气压强理论计算模型。计算时为了满足压强与速度连续条件,响应脉动源与扰动脉动源两者在交界面上需要相互匹配;同时为了能够精确快速地求解三维Green函数,采用了多维切比雪夫(Chebyshev)多项式和渐近展开式快速近似计算方法。计算结果表明所用方法简单可靠,同时计算结果可应用于振荡水柱波能发电系统性能预测及相关问题研究。 相似文献
10.
为解决海洋监测微型传感器供能问题,设计新型波浪能捕获装置,在海面振荡浮筒气室产生空气气柱,驱动介电弹性体形变发电为传感器供能。建立振荡浮子式气柱数值模型,研究新型振荡水柱发电计算理论。利用水动力仿真软件AQWA求解浮子所受波浪力作用振荡幅值、辐射阻尼和附加质量。基于Simulink软件分别计算波浪作用下浮子位移和气室内水柱位移,根据两者的位移差计算气室体积变化所产生的空气压强、介电弹性体发电薄膜形变量和系统输出电能,单次循环周期最大发电量达到24.6 mJ。分析波浪周期、发电薄膜几何参数等对输出电能的影响。 相似文献
11.
You Yage
YuZhi Associated Professor Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou
. Professor Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 《中国海洋工程》1995,(4)
In this paper, the extreme wave loads on an on-shore wave power device are investigated. First, boundary element method is applied to solve the three dimensional potential problem based on the small amplitude wave assumption. Then the motion of the Oscillating Water Column (OWC) inside the device and its laods on the device are calculated in time domain. Several protective techniques often applied are simulated by changing the constraint of the upper end of the chamber of the device. Numerical results are used to judge the effectiveness of these techniques. The investigation shows that damping can not effectively restrain the motion of OWC when the period of incident wave is long, which may cause dangerous loads on the structure. The shut chamber can effectively restrain the motion of OWC, but alternatively cause high pressure in the chamber. A Contracting opening with a Taper (CT) can exhaust a great amount of kinetic energy of OWC, and significantly decrease the loads. It is a promising protective tec 相似文献
12.
The motion and the drift force of a floating OWC (oscillating water column) wave energy device in regular waves are studied taking account of the oscillating surface-pressure due to the pressure drop across the duct of the air chamber. The potential problem inside the chamber is formulated by making use of the Green integral equation associated with the Rankine-type Green function while the outer problem with the Kelvin-type Green function. The added mass, wave damping and excitation coefficients as well as the motion and drift force of the OWC device are calculated for various values of parameter related to the pressure drop. 相似文献
13.
Investigation on the Oscillating Buoy Wave Power Device 总被引：4，自引：0，他引：4
An oscillating buoy wave power device (OD) is a device extracting wave power by an oscillating buoy. Being excited by waves, the buoy heaves up and down to convert wave energy into electricity by means of a mechanical or hydraulic device. Compared with an Oscillating Water Column (OWC) wave power device, the OD has the same capture vvidth ratio as the OWC does, but much higher secondary conversion efficiency. Moreover, the chamber of the OWC, which is the most expensive and difficult part to be built, is not necessary for the OD, so it is easier to construct an OD. In this paper, a nu-merical calculation is conducted for an optimal design of the OD firstly, then a model of the device is built and, a model test is carried out in a wave tank. The results show that the total efficiency of the OD is much higher than that of the OWC and that the OD is a promising wave power device. 相似文献
14.
Wave Energy Converters (WECs) have excellent potential as a source of renewable energy that is yet to be commercially realised. Recent attention has focused on the installation of Oscillating Water Column (OWC) devices as a part of harbor walls to provide advantages of cost–sharing structures and proximity of power generation facilities to existing infrastructure. In this paper, an incompressible three–dimensional CFD model is constructed to simulate a fixed Multi–Chamber OWC (MC–OWC) device. The CFD model is validated; the simulation results are found to be in good agreement with experimental results obtained from a scale physical model tested in a wave tank. The validated CFD model is then used for a benchmark study of 96 numerical tests. These investigate the effects of the PTO damping caused by the power take–off (PTO) system on device performance. The performance is assessed for a range of regular wave heights and periods. The results demonstrate that a PTO system with an intermediate damping can be used for all chambers in the MC–OWC device for most wave period ranges, except for the long wave periods. These require a higher PTO damping. An increased incident wave height reduces the device capture width ratio, but there is a noticeable improvement for long wave periods. 相似文献
15.
Understanding the hydrodynamic interactions between ocean waves and the oscillating water column (OWC) wave energy converter is crucial for improving the device performance. Most previous relevant studies have focused on testing onshore and offshore OWCs using 2D models and wave flumes. Conversely, this paper provides experimental results for a 3D offshore stationary OWC device subjected to regular waves of different heights and periods under a constant power take–off (PTO) damping simulated by an orifice plate of fixed diameter. In addition, a 3D computational fluid dynamics (CFD) model based on the RANS equations and volume of fluid (VOF) surface capturing scheme was developed and validated against the experimental data. Following the validation stage, an extensive campaign of computational tests was performed to (1) discover the impact of testing such an offshore OWC in a 2D domain or a wave flume on device efficiency and (2) investigate the correlation between the incoming wave height and the OWC front wall draught for a maximum efficiency via testing several front lip draughts for two different rear lip draughts under two wave heights and a constant PTO damping. It is found that the 2D and wave flume modelling of an offshore OWC significantly overestimate the overall power extraction efficiency, especially for wave frequencies higher than the chamber resonant frequency. Furthermore, a front lip submergence equal to the wave amplitude affords maximum efficiency whilst preventing air leakage, hence it is recommended that the front lip draught is minimized. 相似文献
16.
为提升波能转换装置的经济竞争力,针对非对称垂荡式振荡水柱（OWC）波能转换装置,基于势流理论和匹配特征函数展开法,通过引入盖根堡多项式近似表征结构尖角附近的流场奇异性行为,深入研究后墙吃水深度（非对称）、墙体厚度和线性弹簧系数对垂荡式OWC装置的波能转换效率、透射系数、气室内平均液面高程等水动力参数的影响规律。研究结果显示,后墙吃水深度及墙体厚度的增加会提升装置在长波区域的高效转换能力,并且显著提高结构物整体阻波防浪性能;线性弹簧的出现,能调节水柱振荡和结构垂荡运动响应之间的相位差,从而有效拓宽垂荡式OWC装置的高效频率带。 相似文献
17.
Oscillating Water Column (OWC) is one of the pioneer devices in harnessing wave energy; however, it is not fully commercialized perhaps due to the complicated hydrodynamic behavior. Previous studies are significantly devoted to OWC devices located in nearshore and coastal regions where incident wave energy would experience dissipation more than offshore. In this paper, a 1:15 scaled fixed offshore OWC model is tested in a large towing tank of National Iranian Marine Laboratory. Wave spectrum shape effect on the efficiency of the OWC model is addressed. Moreover, the paper investigates the effects of the geometric and hydrodynamic factors on OWC device efficiency and uncovers new points in nonlinear interaction occurring inside the chamber; i.e. sloshing. The results indicate that shape of the spectrum inside the chamber is affected by the type of incident wave spectrum, especially for long waves. Pierson–Moskowitz spectrum leaded to higher efficiency rather than JONSWAP spectrum at longer incident wave periods. According to efficiency analysis, increasing wave height may lead to air leakage from the chamber followed by vortex generation, which is a reason for decreasing the efficiency of the OWC device. Furthermore, no shift in the resonant period of the OWC model, due to wave height increase, was observed at the opening ratios equal or smaller than 1.28%. Spectral analysis of water fluctuation inside the OWC chamber illustrates two modes of sloshing. The first mode can be seen at short period waves while the second mode is visible at long period waves. The sloshing modes approximately vanish by increasing draft value. 相似文献
18.
The performance of an oscillating water column (OWC) wave energy converter depends on many factors, such as the wave conditions, the tidal level and the coupling between the chamber and the air turbine. So far most studies have focused on either the chamber or the turbine, and in some cases the influence of the tidal level has not been dealt with properly. In this work a novel approach is presented that takes into account all these factors. Its objective is to develop a virtual laboratory which enables to determine the pneumatic efficiency of a given OWC working under specific conditions of incident waves (wave height and period), tidal level and turbine damping. The pneumatic efficiency, or efficiency of the OWC chamber, is quantified by means of the capture factor, i.e. the ratio between the absorbed pneumatic power and the available wave energy. The approach is based on artificial intelligence—in particular, artificial neural networks (ANNs). The neural network architecture is chosen through a comparative study involving 18 options. The ANN model is trained and, eventually, validated based on an extensive campaign of physical model tests carried out under different wave conditions, tidal levels and values of the damping coefficient, representing turbines of different specifications. The results show excellent agreement between the ANN model and the experimental campaign. In conclusion, the new model constitutes a virtual laboratory that enables to determine the capture factor of an OWC under given wave conditions, tidal levels and values of turbine damping, at a lower cost and in less time than would be required for conventional laboratory tests. 相似文献
19.
A pile-supported OWC breakwater is a novel marine structure in which an oscillating water column (OWC) is integrated into a pile-supported breakwater, with a dual function: generating carbon-free energy and providing shelter for port activities by limiting wave transmission. In this work we investigate the hydrodynamics of this novel structure by means of an analytical model based on linear wave theory and matched eigenfunction expansion method. A local increase in the back-wall draft is adopted as an effective strategy to enhance wave power extraction and reduce wave transmission. The effects of chamber breadth, wall draft and air chamber volume on the hydrodynamic performance are examined in detail. We find that optimizing power take-off (PTO) damping for maximum power leads to both satisfactory power extraction and wave transmission, whereas optimizing for minimum wave transmission penalizes power extraction excessively; the former is, therefore, preferable. An appropriate large enough air chamber volume can enhance the bandwidth of high extraction efficiency through the air compressibility effect, with minimum repercussions for wave transmission. Meanwhile, the air chamber volume is found to be not large enough for the air compressibility effect to be relevant at engineering scales. Finally, a two-level practical optimization strategy on PTO damping is adopted. We prove that this strategy yields similar wave power extraction and wave transmission as the ideal optimization approach. 相似文献