基于遗传算法的水平轴海流发电机叶片优化方法

提出一种基于遗传算法优化(GA)的水平轴海流发电机叶片优化方法,采用Xfoil和BEMT作为分析工具,适用于二维翼型和三维叶片的多目标优化,并以此为基础编写一套叶片优化程序。该优化方法在增加叶片获能效率和减小推力方面具有显著效果,同时对于翼型性能的提升也同样出色。     

FPSO内转塔式系泊系统的接触载荷研究

在介绍两种典型的内转塔式单点系泊系统的基础上,着重探讨了内转塔与船体之间的接触载荷,给出了基于模型试验结果求解内转塔接触载荷的计算公式及接触载荷的分布形式,对某FPS0相关结构的接触载荷进行了计算.结果表明,本文所建议的内转塔式系泊系统的载荷计算方法是可行的,有一定的参考价值.     

船舶系泊系统动力分析

采用悬链线方程对海上船舶系泊系统所采用的缆索进行准静态分析,然后采用拉格朗日方程对缆索进行动态分析,获得缆索的数学模型。给出一组有关船舶动态情况时的三自由度微分方程组,通过比较准静态与动态时缆索的张力特点,可得迎流缆在动态时的最大张力比准静态小等。     

交流发电机系泊试验特殊故障的排除

船舶发电机的负荷试验,是船舶系泊试验中最重要的试验内容。近年来所建造的出口船舶中,发电机组在船舶系泊试验中各式各样的问题和故障也会出现,解决并处理好这些问题对于船舶的系泊试验的顺利进行起着至关重要的作用。     

深水半潜式钻井平台码头抗台风系泊计算分析

深水半潜式钻井平台在码头舾装的周期较长,为确保安全,需对其码头系泊系统进行计算,以得到合理的系泊布置方式。以某深水半潜式钻井平台的码头系泊系统为例,进行风、流载荷共同作用下的抗台风系泊计算分析,建立了多浮体混合带缆系泊系统。     

环境载荷对自升式钻井平台动力响应的影响

为了研究海流载荷、波浪载荷、风载和浮力等环境载荷对自升式钻井平台力学响应的影响,进行了某平台在自存工况和作业工况下的数值分析。分别采用等效梁单元、梁单元、线性弹簧单元和线弹性基础模型来模拟船体、桩腿、船体-桩腿和桩靴-土壤。应用Stokes fifth-order波浪理论模拟水质点的运动规律,得到平台的响应特性。考察了各种环境载荷对平台数值计算结果的影响。结果表明:在自升式平台建模过程中,须要考虑浮力的作用,还应特别关注风载的影响,其次是海流载荷,最后是波浪载荷。     

新型深水绷紧式系泊系统动力特性分析

通过对工作水深为1 500 m的新型绷紧式系泊系统中单根系缆进行动刚度和动张力计算,并与静刚度下计算结果比较,说明了在合成纤维系缆数值计算中考虑其动刚度特性的必要性;传统动刚度计算中将整条系缆作为直线考虑,假定系缆上的应力和应变处处相同,不考虑系缆自身重量,且忽略流体动力作用,这些假设和忽略降低了计算精度;基于集中质量法建立了系缆的动力学模型,提出采用分段动刚度方法通过迭代计算各缆段上的动刚度和动张力,并考虑了系缆自身重量、流体动力和海流等因素的影响;由于传统方法中取预张力作为平均张力计算会降低精度,于是提出基于统计的方法计算各缆段的平均张力,并用于该缆段动刚度的计算。该研究对于绷紧式系泊系统的数值分析和工程应用具有重要的意义。     

系泊索属性对开敞式码头船舶系泊安全的影响分析

结合某工程实例,运用OPTIMOOR系泊分析软件,研究系泊索属性对开敞式码头船舶系泊安全的影响。以减少环境荷载作用下船舶运动量、均衡缆绳张力和减少断缆危险为目标,通过调节缆绳材质、直径,考虑导缆孔到绞盘的距离,增加预张力及缆尾索等方法,以期达到提高开敞式码头船舶系泊安全性的效果,此成果可为码头设计及港口管理人员提供参考。     

基于CFD方法的系泊状态FSO舵载荷计算

舵设备是船舶进行操纵的重要设备,传统舵的性能计算和结构设计多针对航行船舶开展,对系泊在位状态船舶的舵波浪载荷关注较少。采用CFD方法,针对一艘系泊在位状态下FSO(floating storage and offloading)在遭遇极端波浪时的舵载荷进行计算。首先根据FSO临界作业条件评估船体与波浪的最大遭遇角度,然后建立数值波浪水池,评估最大遭遇角状态在实际海况下的舵力矩特征。研究结果表明,在极端海况下的舵力矩会超出规范设计舵力矩,会对舵系结构安全造成威胁。本文研究成果可为同类型舵结构的设计提供参考。     

FPSO系泊系统参数的动力效应影响分析

利用水动力分析软件AQWA研究了内转塔式单点系泊参数对海上浮式生产储油船FPSO（floating production,storage and affcoading system）系统动力效应的影响特性,定量分析了内转塔位置、系泊缆材料分布、系泊缆预张力、系泊缆数量、系泊缆布置形式等参数对FPSO系统动力效应的影响,对每个系泊参数采取多个特征量进行比较分析,计算结果表明：转塔位置距船艏柱25%Lpp时风标效应及定位效果最好,多成分系泊缆材料分布采取下端钢链9%、聚酯缆90%、上端钢链1%时,系泊缆数量取9根且为3组×3根/组布置时定位效果最好,缆绳受力最小.以FPSO水平偏移量与系泊缆的安全系数为目标,提出了一套系泊系统的优选方案,计算结果表明系泊性能优良,与初步设计方案相比有了显著地提高.文中的计算及分析结果对内转塔式FPSO系泊系统的设计具有一定指导意义.     

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.     

Monitoring blade loads for a floating wind turbine in wave basin model tests using Fiber Bragg Grating sensors: A feasibility study

The blade loading contains sufficient information about the unsteady aerodynamics of Floating Wind Turbines (FWTs), and it serves as the basis for advanced controller developments. Wave basin model test is among the most reliable and economical methods for FWT investigations. However, few FWTs were reported being able to monitor the blade loads during wave basin tests. The main obstacles include strict space/mass limitations in model manufacturing and problems associated with signal transmission between rotating blades and stationary signal processing unit. In this paper, the feasibility of detecting blade loads for model FWT in wave basin tests is investigated. An on-line monitoring system is developed based on Fiber Bragg Grating (FBG) sensors and a Fiber Optical Rotary Joint (FORJ). Extensive validation tests are conducted under different environmental and operational conditions. Results show that the proposed FBG-FORJ sensing system presents impressive feasibility and reliability. As the authors know, it is among the first attempts to monitor the blade loads in real-time for model FWTs in wave basin tests. The present study will serve to enrich the knowledge about unsteady aerodynamics of FWTs and lay the foundation for experimental studies on advanced FWT controllers.     

Fluid-structure interaction and stress analysis of a floating wind turbine

In this paper, we describe a method to investigate the fluid-structure interaction of a floating wind turbine and to analyze the global deformations and the corresponding stresses with a detailed finite element model. To solve the fluid-structure interaction problem, a partitioned approach is chosen. The in-house C++ library comana, which was developed to solve multi-physic problems by coupling existing solvers, is extended to couple the fluid solver panMARE and the structural solver ANSYS. The significance of the interaction of structural deformations and the fluid loads is pointed out for the rotor of the wind turbine. In order to enable the use of a detailed finite element model in the fluid-structure interaction simulation, a model reduction method is applied in ANSYS. As a result, an efficient stress analysis can be performed under consideration of the fluid-structure interaction.     

Design,modelling, and analysis of a large floating dock for spar floating wind turbine installation

Installation of floating wind turbines at the offshore site is a challenging task. A significant part of the time efficiency and costs are related to the installation methods which are sensitive to weather conditions. This study investigates a large floating dock concept, which can be used to shield a floating wind turbine during installation of tower, nacelle, and rotor onto a spar foundation. In this paper, the concept is described in detail, and a design optimisation is carried out using simple design constraints. Hydrodynamic analysis and dynamic response analysis of the coupled system of the optimum dock and spar are conducted. Two spars of different sizes are considered, and the motion responses of the spars with and without the dock in irregular waves are compared. Through analysis of the motion spectra and response statistics, dynamic characteristics of the coupled system is revealed. The present design of the dock reduces the platform-pitch responses of the spars and potentially facilitates blade mating, but may deteriorate the heave velocity of the spars in swell conditions. Finally, future design aspects of the floating dock are discussed.     

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.     

Hydroelastic code-to-code comparison for a tension leg spar-type floating wind turbine

The development of robust design tools for offshore wind turbines requires knowledge of both wave and wind load models and response analysis. Verification of the numerical codes is required by the use of experiments and code-to-code comparisons. This paper presents a hydroelastic code-to-code comparison between the HAWC2 and USFOS/vpOne codes for a tension leg spar (TLS) wind turbine with a single tether. This concept is hence based on the TLP and Spar concepts. The comparison is performed using coupled hydroelastic time domain simulations. Several aspects of modelling, such as wave simulation, hydrodynamic and structural modelling, are addressed for the TLS. Wave-induced motions of the support structure affect the power performance of a wind turbine. Furthermore, overload of the tension leg should be avoided. In this paper, the motion and tension responses are compared. The tension leg introduces nonlinear effects on the spar motion. These nonlinear effects include combined-frequency effect such as double, difference and sum of wave, as well as natural pitch and surge frequencies. Hydrodynamic loads are based on a combination of the Morison formula and the pressure integration method. A comparison indicates that the motion and tension responses obtained in the two codes are in good agreement.     

漂浮式潮流电站系泊系统疲劳性能预报(英文)

As a kind of clean and renewable energy,tidal current energy is becoming increasingly popular all over the world with the shortage of energy and environmental problems becoming more and more severe.A floating tidal current power station is a typical type of tidal current power transformers which can sustain the loads of wind,waves,and current,and even the extreme situation of a typhoon.Therefore,the mooring system must be reliable enough to keep the station operating normally and to survive in extreme situations.The power station examined in this paper was installed at a depth of 40 m.A 44 mm-diameter R4-RQ4 chain was chosen,with a 2 147 kN minimum break strength and 50 kN pretension.Common studless link chain was used in this paper.Based on the Miner fatigue cumulative damage rule,S-N curves of chains,and MOSES software,a highly reliable mooring system was designed and analyzed.The calculation results show that the mooring system designed is reliable throughout a 10-year period.It can completely meet the design requirements of American Petroleum institution(API).Therefore,the presented research is significant for advancing the design of this kind of power station.     

浮式生产储油船锚泊定位性能计算

应用计算锚链的悬链线方程和计算船舶运动的格林函数方法的耦合数值方法，对一锚泊的浮式生产储油船进行了定位性能计算，给出了自由状态与锚泊状态系统的运动响应特性的对比、不同状态与工况的锚泊浮体的运动性能参数以及锚链承受的张力等计算结果。研究成果可以为浮式生产储油船锚泊系统设计、校核计算和锚泊系统形式与参数优化提供初步计算结果以及用于设计方案的比较。     

FPSO单点系泊系统动力截断优化设计

浮体系泊系统在海洋工程水池进行模型试验时,由于水池尺度有限,首先对系泊线进行等效截断设计,是被动式混合模型试验的重要一步。截断设计时,基于细长杆理论,模拟系泊线的非线性动力特性,将计算所得时域内的系泊力转换到频域响应,选择有代表性的频率及响应建立目标函数,结合NSGA II优化算法,确定最优截断系泊参数,计算快速准确。针对一作业水深420m的FPSO单点系泊系统,进行水平截断设计。截断前后系泊系统和单根系泊线的静力特性吻合很好。截断系泊系统在不同环境载荷作用下的总体响应和系泊动力,都与截断前一致。证明了截断设计的合理性和准确性,为后续的模型试验工作打下了基础。