Deep ocean wave energy conversion using a cycloidal turbine     

S.G. Siegel  T. JeansT.E. McLaughlin 《Applied Ocean Research》2011,33(2):110-119

A lift based wave energy converter, namely, a cycloidal turbine, is investigated. This type of wave energy converter consists of a shaft with one or more hydrofoils attached eccentrically at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. In the two-dimensional limit, i.e. for large spans of the hydrofoil (or an array of these), the geometry of the converter is suitable for wave termination of straight crested Airy waves. Results from two-dimensional potential flow simulations, with thin hydrofoils modeled as either a point vortex or discrete vortex panel, are presented. The operation of the cycloidal turbine both as a wave generator as well as a wave-to-shaft energy converter interacting with a linear Airy wave is demonstrated. The impact on the performance of the converter for design parameters such as device size, submergence depth, and number of hydrofoils is shown. For optimal parameter choices, simulation results demonstrate inviscid energy conversion efficiencies of more than 99% of the incoming wave energy to shaft energy. This is achieved using feedback control to synchronize the rotational rate, blade pitch angle, and phase of the cycloidal wave energy converter to the incoming wave. While complete termination of the incoming wave is shown, the remainder of the energy is lost to harmonic waves traveling in the up-wave and down-wave directions.  相似文献   

Wave run-up on cylindrical and cone shaped foundations for offshore wind turbines     

Leen De Vos  Peter Frigaard  Julien De Rouck 《Coastal Engineering》2007

During the last decade, several offshore wind-farms were built and offshore wind energy promises to be a suitable alternative to provide green energy. However, there are still some engineering challenges in placing the foundations of offshore wind turbines. For example, wave run-up and wave impacts cause unexpected damage to boat landing facilities and platforms. To assess the forces due to wave run-up, the distribution of run-up around the pile and the maximum run-up height need to be known. This article describes a physical model study of the run-up heights and run-up distribution on two shapes of foundations for offshore wind turbines, including both regular and irregular waves. The influence of wave steepness, wave height and water depth on run-up is investigated. The measured run-up values are compared with applicable theories and previous experimental studies predicting run-up on a circular pile.  相似文献   

Dynamic Responses of A Semi-Type Offshore Floating Wind Turbine During Normal State and Emergency Shutdown   总被引：1，自引：1，他引：0       下载免费PDF全文

胡志强  李良  王晋  胡秋皓  沈马成 《海洋工程》2016,(1):97-112

This paper addresses joint wind-wave induced dynamic responses of a semi-type offshore floating wind turbine (OFWT) under normal states and fault event conditions. The analysis in this paper is conducted in time domain, using an aero-hydro-servo-elastic simulation code-FAST. Owing to the unique viscous features of the reference system, the original viscous damping model implemented in FAST is replaced with a quadratic one to gain an accurate capture of viscous effects. Simulation cases involve free-decay motion in still water, steady motions in the presence of regular waves and wind as well as dynamic response in operational sea states with and without wind. Simulations also include the cases for transient responses induced by fast blade pitching after emergency shutdown. The features of platform motions, local structural loads and a typical mooring line tension force under a variety of excitations are obtained and investigated.  相似文献   

Optimization of Blade Motion of Vertical Axis Turbine     

马勇  张亮  张之阳  韩端锋 《海洋工程》2016,(2):297-308

In this paper, a method is proposed to improve the energy efficiency of the vertical axis turbine. First of all, a single disk multiple stream-tube model is used to calculate individual fitness. Genetic algorithm is adopted to optimize blade pitch motion of vertical axis turbine with the maximum energy efficiency being selected as the optimization objective. Then, a particular data processing method is proposed, fitting the result data into a cosine-like curve. After that, a general formula calculating the blade motion is developed. Finally, CFD simulation is used to validate the blade pitch motion formula. The results show that the turbine’s energy efficiency becomes higher after the optimization of blade pitch motion; compared with the fixed pitch turbine, the efficiency of variable-pitch turbine is significantly improved by the active blade pitch control; the energy efficiency declines gradually with the growth of speed ratio; besides, compactness has lager effect on the blade motion while the number of blades has little effect on it.  相似文献   

共水平轴双叶轮海流机水动力学性能的实验研究     

程友良  雷朝  戴峥峥  陈健梅  吴百公 《海洋技术学报》2016,(1):106-112

针对水平轴单叶轮海流机在低流速时启动性能差、获能少的缺点,采用共水平轴同向旋转双叶轮水轮机进行了水动力学性能的水槽试验.由实验结果研究了共水平轴单叶轮和双叶轮水轮机的功率特性和启动特性,分析了不同上、下游叶轮安装角和叶轮轴向间距对叶轮启动水流速度以及发电机获得功率的影响,并对单叶轮和双叶轮水轮机的运行情况进行了比较.结果表明,共水平轴双叶轮水轮机的启动水流速度较单叶轮低很多,而且能从水流中获得更多的能量.因此,共水平轴双叶轮水轮机能改进一般水平轴单叶轮水轮机难以启动和获能少的不足,更适合于我国低海流流速的实际海况.  相似文献   

水平轴潮流能水轮机数值模拟方法对比分析     

廖微  王兵振  张巍  段云琪 《海洋技术学报》2016,(1):113-117

叶素动量理论和CFD方法是水平轴潮流能水轮机性能分析中运用较为广泛的数值模拟方法,文中结合小尺寸水轮机模型试验,对比分析了叶素动量理论和CFD方法在水轮机性能分析中的准确性和适用性.验证结果表明:叶素动量理论和CFD方法均能对水轮机的性能进行预报,且CFD精度高于动量叶素理论;大尖速比时,动量叶素理论偏离较高,不再适合性能预报;在小尖速比下,建议采用RNGk-ε模型的CFD方法进行分析计算;动量叶素理论适合设计初期设计方案的对比分析,而CFD方法适合对设计结果的验证校核和详细分析.  相似文献   

风电场流场特性及风机布局数值模拟研究   总被引：1，自引：0，他引：1  

张思瑶  赵超  隋东  张菁  王学涛 《气象与环境学报》2021,37(2):101-106

针对风电场流场特性研究对风力机工作性能提高的重要意义,采用计算流体力学（CFD）方法在单机风力机模拟验证的基础上,对某风电场单风力机和三种布局条件下的风电场流场特性进行了数值模拟研究。考察了不同布局条件下风电场速度、叶轮表面压力以及湍流涡的分布特性。结果表明：叶轮后方尾流效应明显,速度损失随着相对距离的增加而逐渐减小,风力机处中心尾流速度比率最低降为0.4;当相对距离超过4 d后,风速可恢复为初始速度的90%以上;尾流速度与涡流粘性呈负相关性;三风力机平行布置时,各风力机尾流速度比率基本一致;三风机组在错落布置时,尾流效应对下游风力机工作性能影响较小,错落角度越大,尾流损失越小。  相似文献   

运行状态下海上单桩风机系统自振频率分析          下载免费PDF全文

王丕光  刘晶波  赵密 《地震工程学报》2021,43(3):704-709

系统自振频率限制是海上风机结构设计中的一个关键因素。运行状态下风机动力荷载会引起基础的水平侧移,较大的水平侧移会导致基础刚度的降低,进一步影响风机系统的自振频率。该文基于有限元软件ABAQUS平台,建立单桩式海上风机结构系统的自振频率数值模型,并讨论运行状态下基础水平侧移对大直径海上风机系统自振频率的影响。模型中考虑了塔筒的变截面特性;桩-土相互作用通过p-y曲线方法模拟;桩和塔采用梁单元模拟;通过Pushover分析汇总出水平侧移引起的桩顶水平刚度。研究结果表明:桩基侧向位移会降低风机结构体系的自振频率;桩基侧向位移对基频的影响较小,对高阶频率的影响显著;大直径海上风机的频率计算中可忽略风机运行状态对体系自振频率的影响。  相似文献   

近钻头随钻测量系统及其小型化设计关键技术分析          下载免费PDF全文

韦海瑞  朱芝同  吴川  邵玉涛  赵洪波  刘广  贾炜  董巍  张化民  贾明浩  薛倩冰 《探矿工程》2022,49(5):156-162

近钻头随钻测量技术是石油钻井领域最具有发展前景的高新技术之一,它以近钻头地质参数与工程参数的随钻测量、传输、信息解释、决策控制为主要技术特征,能有效提高油气层钻遇率、降低钻井成本。本文介绍了近钻头测量系统国内外的发展与应用现状,阐述了系统的工作原理、结构组成与特点,为满足小口径钻进对近钻头测量技术的需求,提出了小型化设计亟待攻克的关键技术难题,包括电磁波无线通信抗干扰技术、小直径涡轮发电技术、井下MEMS传感器技术等,为今后小直径近钻头测量系统研发提供技术基础。  相似文献   

国电赤峰某风力发电机组基础受力分析     

李桂庆  刘少云  朱思慧 《中国勘察设计》2010,(4):65-67

根据风机基础的受力特点,分析了正常运行工况和极端荷载工况下,圆板式扩展基础的受力特点,并借助相关辅助计算程序,得出了合理的结论,供相关科研及设计参考。  相似文献