南海风浪条件下Spar式浮式风机平台的构型及参数

使用WAMIT软件建立OC3-Hywind Spar式浮式风机模型,联合FAST软件计算浮式风机在不同工况下的幅值响应算子;结合为南海海域波浪条件优化后的JONSWAP谱,对浮式风机进行不同工况下的响应谱分析及最大响应值计算,进一步阐述浮式平台结构构型参数的变化对整体结构在南海相应工况下的运动影响。     

海上浮式风机平台的水动力分析

针对深海海域,设计了适用于深海的新型浮式风机平台,计算了平台在频域内的运动响应,结果表明平台运动的固有频域远离常见波浪频率。计算了平台在时域内工作工况下的运动响应,计算得到了不同工况下风机运动的最大响应值,并且给出建议的风机工作风速区间。计算了平台在极限工况下的运动响应,计算结果表明平台在极限工况下运动响应良好,能够适应恶劣海洋环境。对平台运动响应进行频谱分析,分析表明平台在风和波浪共同作用下的运动可分为与锚链和平台固有频率有关的低频部分和与波浪频率有关的高频部分。     

Spar基础浮式风机系泊系统全耦合分析

本文以OC3 Hywind Spar基础浮式风机为研究对象,采用先进的空气动力-水动力耦合时域分析方法,针对其在中国南海某海域风浪流共同作用下,系泊系统、浮式基础运动以及风机与塔桶载荷响应进行分析。对比了定常风与湍流风模型对浮式风机系泊系统、整体运动响应以及风机载荷的影响。计算结果表明：相比于湍流风,采用定常风进行浮式风机系泊系统分析将得到偏于危险的结果,同时浮式风机运动响应与风机载荷结果偏小。本文建议在系泊系统初始设计阶段采用定常风方法进行设计,在系泊分析阶段采用湍流风进行分析,以保证浮式风机长期服役安全。     

塔柱和风机位置对半潜式浮式风机系统动力性能的影响研究

研究塔柱和风机布置位置对半潜式浮式风机系统动力性能的影响。以OC4-deepCwind浮式风机参数为例,将塔柱和风机分别布置在半潜式浮式基础的中心和其三角形浮筒上,建立浮式风机系统动力学模型,计算不同工况下系统的动力响应。结果表明,塔柱和风机由基础中心调到其浮筒上后,浮式基础运动、机舱加速度、叶片气动力及系缆力的平均值变化不大,标准差有显著的增加;特别在极限工况,机舱X向加速度、叶片气动力的标准差增加近1倍,首摇超过5°,1号缆受力的标准差增加约30%。实际设计中,综合考虑浮式风机系统动力性能、安装和运输过程的便利性及结构强度等设计塔柱和风机位置。     

浮式风机限制性耦合与全耦合数值计算

浮式风机上部风机与下部浮式平台通常是由不同的设计单位设计的，因此在进行浮式平台设计时无法获得上部风机参数，进而无法对浮式风机的水动力性能进行全耦合数值计算分析。为此，以OC3-Spar和OC4-Semi两种浮式风机为研究对象，通过在其不同位置施加不同等效载荷，设计不同的限制性耦合方式。在工作海况下对浮式风机进行限制性耦合计算，实现对浮式风机水动力性能的研究，并将所得结果与全耦合方式的计算结果进行对比。结果表明，在轮毂中心处施加风机等效推力对于单柱式和半潜式浮式风机而言均是最优限制性耦合方式。当采用该方式时，工作海况下2种浮式风机的时域结果均与全耦合计算结果具有较高的吻合度，响应谱频率分布与全耦合结果基本一致，但幅值均相差较大。     

Spar基础浮式风机系泊系统全耦合分析

以OC3 Hywind Spar基础浮式风机为研究对象,采用先进的空气动力-水动力耦合时域分析方法,对其在中国南海某海域风浪流共同作用下的系泊系统、浮式基础运动以及风机和塔架载荷响应进行分析,对比定常风与湍流风模型对浮式风机系泊系统、整体运动响应以及风机载荷的影响。计算结果表明:相比于湍流风,采用定常风进行浮式风机系泊系统分析将得到偏于危险的结果,并且,浮式风机运动响应与风机载荷结果偏小。因此,建议在系泊系统初始设计阶段采用定常风方法进行设计,在系泊分析阶段采用湍流风进行分析,以保证浮式风机的长期服役安全。     

海上混合式风机基础动力响应研究

针对海上风机的发展趋势,对一种混合式海上浮式风机基础的动力响应进行了研究。应用SESAM软件和FAST软件分别建立海上风机的下部浮式基础以及上部结构的数值模型,调用Aero Dyn程序包计算结构的空气动力载荷。分析系统的动态响应和基础的运动特性。改变筋腱预张力的大小,研究其对浮式基础运动响应的影响,为海上风机混合式基础的初步设计提供一定的理论依据。     

海上半潜式浮式风机平台系泊系统对比研究

选取5MW-OC4深水半潜式浮式风机平台为参考模型,利用AQWA软件建立半潜式浮式风机平台模型,在频域范围内计算浮式风机平台运动响应,得到平台幅频响应曲线,以验证数值分析的可靠性。选取3种浮式风机平台系泊系统,对比研究系泊系统改变对浮式风机平台运动响应的影响规律,同时分析极端环境条件下单缆失效对浮式平台运动响应及系泊缆张力的影响。计算结果对浮式风机平台系泊系统的优化设计有一定的参考意义。     

半潜浮式风机的动力响应分析

OC4半潜浮式风机综合性能较好，但其浮式基础结构质量和结构复杂性使其建造成本高昂，而WindFloat半潜浮式风机浮式基础具有结构简单、建造成本低和减摇效果好等优点，但是适应水深较小且只适合特定海域。结合OC4和WindFloat半潜浮式风机浮式基础的结构特点，针对200 m水深环境设计OC4-WindFloat半潜浮式风机基础。基于叶素理论、莫里森公式和势流理论，通过有限元软件对OC4-WindFloat半潜浮式风机的固有周期及风浪联合作用下的动态响应进行耦合分析，并与OC4半潜浮式风机结果进行对比研究。结果显示，OC4-WindFloat半潜浮式风机固有周期及动态响应均满足相关规定，且具有比OC4更低的建造成本，相比WindFloat可适用更深的海域。研究结果对于浮式基础型式研究有一定的指导意义。     

半潜漂浮式风机稳性数值分析

针对半潜浮式风机稳性分析的特殊性,借鉴传统半潜海工平台设计经验,结合海上浮式风机结构高耸性特点,参考稳性相关规范,提出一种半潜浮式风机稳性分析方法,应用稳性分析专业软件NAPA,数值仿真计算半潜浮式风机的完整稳性和破损稳性,结果表明,浮式风机在各典型工况下不会发生倾覆或沉没,满足风机稳性安全及正常运行发电要求。     

Stochastic dynamic load effect and fatigue damage analysis of drivetrains in land-based and TLP,spar and semi-submersible floating wind turbines

This paper deals with the feasibility of using a 5 MW drivetrain which is designed for a land-based turbine, on floating wind turbines. Four types of floating support structures are investigated: spar, TLP and two semi-submersibles. The fatigue damage of mechanical components inside the gearbox and main bearings is compared for different environmental conditions, ranging from cut-in to cut-out wind speeds. For floating wind turbines, representative wave conditions are also considered. All wind turbines are ensured to follow similar power curves, but differences in the control system (integral to different concepts) are allowed. A de-coupled analysis approach is employed for the drivetrain response analysis. First, an aero-hydro-servo-elastic code is employed for the global analysis. Next, motions, moments and forces from the global analysis are applied on the gearbox multi body model and the loads on gears and bearings are obtained. The results suggest that the main bearings sustain more damage in floating wind turbines than on land-based. The highest main bearing damage is observed for the spar floating wind turbine. The large wave induced axial load on the main shaft is found to be the primary reason of this high damage in the spar wind turbine. Apart from the main bearings - which are located on the main shaft outside the gearbox - other bearings and gears inside the gearbox hold damages in floating wind turbines equal or even less than in the land-based turbine. It is emphasized that the results presented in this study are based on a drivetrain with two main bearings, which considerably reduces the non-torque loads on the gearbox.     

浮式海上风力机运动性能和锚泊系统(英文)

The development of offshore wind farms was originally carried out in shallow water areas with fixed(seabed mounted) structures.However,countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas.The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform.This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine(FOWT) system.The wind turbine was modeled as a wind block with a certain thrust coefficient,and the hydrodynamics and mooring system dynamics of the platform were calculated by SESAM software.The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined.The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.     

浮式风机气动-水动耦合特性数值模拟（英文）

The exploration for renewable and clean energies has become crucial due to environmental issues such as global warming and the energy crisis. In recent years,floating offshore wind turbines(FOWTs) have attracted a considerable amount of attention as a means to exploit steady and strong wind sources available in deep-sea areas. In this study, the coupled aero-hydrodynamic characteristics of a spar-type 5-MW wind turbine are analyzed. An unsteady actuator line model(UALM) coupled with a twophase computational fluid dynamics solver naoe-FOAM-SJTU is applied to solve three-dimensional Reynolds-averaged NavierStokes equations. Simulations with different complexities are performed. First, the wind turbine is parked. Second, the impact of the wind turbine is simplified into equivalent forces and moments. Third, fully coupled dynamic analysis with wind and wave excitation is conducted by utilizing the UALM. From the simulation, aerodynamic forces, including the unsteady aerodynamic power and thrust, can be obtained, and hydrodynamic responses such as the six-degrees-of-freedom motions of the floating platform and the mooring tensions are also available. The coupled responses of the FOWT for cases of different complexities are analyzed based on the simulation results. Findings indicate that the coupling effects between the aerodynamics of the wind turbine and the hydrodynamics of the floating platform are obvious. The aerodynamic loads have a significant effect on the dynamic responses of the floating platform, and the aerodynamic performance of the wind turbine has highly unsteady characteristics due to the motions of the floating platform. A spar-type FOWT consisting of NREL-5-MW baseline wind turbine and OC3-Hywind platform system is investigated. The aerodynamic forces can be obtained by the UALM. The 6 DoF motions and mooring tensions are predicted by the naoe-FOAM-SJTU. To research the coupling effects between the aerodynamics of the wind turbine and the hydrodynamics of the floating platform, simulations with different complexities are performed. Fully coupled aero-hydrodynamic characteristics of FOWTs, including aerodynamic loads, wake vortex, motion responses, and mooring tensions, are compared and analyzed.     

Dynamic analysis of a dual-spar floating offshore wind farm with shared moorings in extreme environmental conditions

The concept of a shared mooring system was proposed to reduce mooring and anchoring costs. Shared moorings also add complexity to the floating offshore wind farm system and pose design challenges. To understand the system dynamics, this paper presents a dynamic analysis for a dual-spar floating offshore wind farm with a shared mooring system in extreme environmental conditions. First, a numerical model of the floating offshore wind farm was established in a commercial simulation tool. Then, time-domain simulations were performed for the parked wind farm under extreme wind and wave conditions. A sensitivity study was carried out to investigate the influence of loading directions and shared line mooring properties. To highlight the influence of the shared line, the results were compared to those of a single spar floating wind turbine, and larger platform motions and higher tension loads in single lines are observed for the wind farm with shared moorings. The loading direction affects the platform motions and mooring response of the floating offshore wind farm. Comparing the investigated loading directions to the 0-deg loading direction, the variation of mean mooring tension at the fairlead is up to 84% for single lines and 16% for the shared line. The influence of the shared line properties in the platform motions and the structural responses is limited. These findings improve understanding of the dynamic characteristics of floating offshore wind farms with a shared mooring system.     

海上风电浮船分体安装运动响应数值仿真分析

本文采用数值仿真手段分析浮吊船的运动响应以确定采用浮吊船进行风电机组分体安装的可行性。利用基于边界元法的水动力学数值仿真的手段，计算强峰1800和苏连海起重08两艘起重船的浮体运动响应RAO。采用频域谱分析的方法，计算随机波条件下两船吊钩位置的垂荡运动响应谱，并通过波浪谱统计规律确定船舶的最大运动响应以及加速度响应，以确定风电机组分体安装的可行性。     

海上风力发电浮式基础的研究进展及关键技术问题

水深大于50m的海域,风速稳定、风切变小,具有风力发电的独特优势,该海域风力发电装备需要采用浮式基础,因此研究适用于海上风力发电的浮式基础结构,对海上风力发电的产业化具有重要的意义。近年来国外开展了各种新颖浮式基础结构基础形式和工作原理的研究,针对浮式基础承受的风机运转载荷和海洋环境载荷的特点,系统分析海上风机浮式基础涉及到的关键技术问题和风险因素,对风机浮式基础设计具有参考价值。     

单柱式浮式风力机动力响应数值与试验分析

以200 m作业水深的5 MW OC3单柱式浮式风力机为研究对象,采用FAST程序对其在不同海况下的运动进行全耦合时历数值计算,并与采用1∶50缩尺比模型试验所得时历结果进行对比,通过时域以及频域方法对平台主要自由度运动以及系泊拉力进行分析。研究发现:垂向运动带来的自由面记忆效应较纵向和横向小;悬链线式模型所能提供的系泊拉力较张紧式系泊提供的拉力小;风浪联合作用下,风载荷主要激励低频固有频率运动,波浪载荷则主要激励波频运动;平台纵荡和纵摇运动受系泊系统的影响较大,而垂荡运动则不受系泊系统的影响。     

Active heave compensation of floating wind turbine installation using a catamaran construction vessel

The application of floating wind turbines is limited by the high cost that increases with the water depth. Offshore installation and maintenance continue to consume a high percentage of the project budget. To improve the installation efficiency of the floating offshore wind turbine, a novel concept is proposed by the SFI MOVE project. Several wind turbine superstructure components are preassembled onshore and carried to the installation site by a catamaran construction vessel. Each assembly can then be installed using only one lift, and the concept is less sensitive to weather conditions. In this paper, a control algorithm of the proposed hydraulic active heave compensator system is developed using singular perturbation theory to cancel the relative motion between the spar top and gripped preassembly bottom. Closed-loop stability is proven, and the simulation results show that the installation efficiency is improved with an increase in the acceptable weather conditions.