平台内TMD对新型Barge浮式风机振动抑制的研究

Barge型浮式风机是发展海上风电的重要装备,其运动响应可以通过被动控制装置调谐质量阻尼器(tuned mass damper,TMD)有效抑制。基于ITI Energy Barge风机,本研究设计了新型Barge浮式风机基础,建立平台配置TMD的风机动力学模型,在浮动平台内配置不同位置、质量、阻尼参数TMD,研究风浪载荷作用下风机平台配置最优参数TMD前后浮式风机运动响应的变化。结果表明:在新型风机平台内浮筒顶部配置质量比3%、阻尼比6%的TMD后,风机塔顶前后和左右位移分别减小15.56%、44.93%,平台纵摇和横摇抑制率达到22.97%、62.79%,风机塔基前后和左右弯矩分别减少15.62%、39.8%。此时,TMD控制效果最佳,风机整体稳定性大幅提高。

Research on optimization of valve open time of the launch barge's ballast tanks

Launch barge is an effective tool for transporting ship segments from one place to another in shipyards. During shifting of segments onto a barge, the slideway on the barge＇s deck must be adjusted to maintain the same level as the wharf and also the barge must be kept level by adjusting the water in the ballast tanks. When to open the adjusting valves is an important factor influencing the barge＇s trim during the water-adjustment process. Because these adjustments are complex a mathematical model was formulated,after analyzing the characteristics of the process of moving the segments onto the barges deck, and considering the effects of this movement＇s speed and variations in tidal levels during the move. Then the model was solved by the penalty function method, the grid method, and improved simulated annealing, respectively. The best optimization model and its corresponding solution were then determined. Finally, it was proven that the model and the method adopted are correct and suitable, by calculating and analysing an example.

极限海况下Barge平台漂浮式风电场动态响应

为提高漂浮式风力机平台稳定性,以Barge平台漂浮式风力机为研究对象,建立共用系泊系统3×3阵列Barge平台的漂浮式风电场。以叶素动量理论为基础,利用水动力学软件AQWA并结合有限元方法,对Barge平台漂浮式风电场和单个Barge平台在极限海况下考虑风波耦合作用的动态响应进行对比研究。结果表明,相较于单个Barge平台,风电场中各个平台的纵荡响应均小于单个Barge平台,位于两侧的各个平台产生不规则的横荡运动,但均较小;其次,Barge平台风电场的垂荡、纵摇及机舱加速度响应均优于单个Barge平台;同时,风电场中各平台表现出很好的首摇、横摇稳定性,波动幅度均未超过2°。研究结果验证了所建立的Barge平台漂浮式风电场的可行性,可为进一步开展新型漂浮式风电场研究提供理论依据。

Barge平台漂浮式风力机动态响应及稳定性控制研究

将调谐质量阻尼器(TMD)配置于漂浮式风力机机舱或塔架可提高其整体稳定性,但加剧了塔基疲劳载荷。为此,在平台内部配置TMD进行减振控制,以ITI Barge平台为研究对象,建立漂浮式风力机动力学模型,研究塔顶前后和侧向位移随TMD质量、阻尼及安装位置的变化规律,采用多岛遗传算法求得最优TMD参数,对比分析风波载荷作用下无TMD控制、机舱TMD控制及平台TMD控制对漂浮式风力机动态响应特性的影响。结果表明:塔顶前后和侧向位移随平台TMD参数变化较为显著,当位于相同位置处TMD质量和阻尼较大时,塔顶前后和侧向位移明显减小,平台TMD质量和阻尼不变时,塔顶前后和侧向位移随TMD位置升高逐渐减小。风波载荷作用下,TMD对漂浮式风力机动态响应控制效果较为明显,但各部位控制效果不同,塔顶侧向位移、平台横摇角及塔基横摇弯矩控制效果最为显著。此外,较之机舱TMD控制,平台TMD控制时漂浮式风力机稳定性更好。

Study on TMD Control on Stability Improvement of Barge-Supported Floating Offshore Wind Turbine Based on the Multi-Island Genetic Algorithm

A floating offshore wind turbine (FOWT) has a great potential in producing renewable energy as offshore wind resource is rich in deep sea area (water deeper than 60 m) where fixed foundations are cost-effective or deployable. However, compared with a fixed-bottom installation, FOWT has to suffer more extreme loads due to its extra degrees of freedom. Therefore, the stability of an FOWT is a key challenge in exploiting offshore deep-water wind. Focusing on the stability of barge-type FOWT, this paper is to investigate the effect of passive structural control by equipping a tuned mass damper (TMD) on the nacelle. The turbulent wind with sharp fluctuations is established both in velocity and inflow direction based on standard Kaimal turbulence spectrum as suggested in the standard IEC61400-2. The irregular wave is generated according to the Pierson-Moskowitz spectrum. The dynamic structural characteristics of FOWT are calculated based on the fully coupled aero-hydro-servo-elastic solver FAST. Evidence has shown that the proposed method of the nacelle-based TMD is effective in controlling stability of an FOWT, as the sway and roll motions of barge and the side-side displacement of tower top decreased significantly. With the increase of mass, the side-side displacement of tower-top and the amplitude of roll motion of barge reveal a trend of increasing first and then decreasing. The stiffness and damping have little effect. Furthermore, the multi-island genetic optimization algorithm (MIGA) is employed to find globally optimum structural parameters (mass, stiffness and damping) of the TMD. The optimum structure parameters of TMD are achieved when the mass is 21393 kg, damping is 13635 N/(m/s) and stiffness is 6828 N/m. By adopting the optimized TMD, stability of roll motion of barge and side-side displacement of tower-top increase up to 53% and 50% respectively when compared with the normal TMD. The simulation results verify the validity and reliability of the proposed TMD control and the optimization methods.

Numerical investigation of influence of wave directionality on the water resonance at a narrow gap between two rectangular barges

A three-dimensional time-domain potential flow model with second-order nonlinearity was applied to simulate the wave resonance in a gap between two side-by-side rectangular barges. In the model, the velocity potential was decomposed into the incident potential and unknown scattered potential which was obtained by solving the boundary integral equation. The fourth-order predict-correct method was applied to enforce the free surface conditions in the time integration. The influence of the wave direction on the first and second-order gap surface elevations was investigated. The results reveal that the incident wave angle does not affect the resonant wave frequency and the maximum surface elevation at resonance always occurs at the middle location along the gap. However, the corresponding maximum wave surface elevation at resonance varies with the incident wave angle. The location of the maximum wave elevation shifts either upstream or downstream along the gap, depending on the relative magnitude of incident wave frequency to the resonant frequency.

Comparison of Microbubble and Air Layer Injection with Porous Media for Drag Reduction on a Self-propelled Barge Ship Model

Ship resistance issues are related to fuel economy,speed,and cost efficiency.Air lubrication is a promising technique for lowering hull frictional resistance as it is supposed to modify the energy in the turbulent boundary layer and thereby reduce hull friction.In this paper,the objective is to identify the optimum type of air lubrication using microbubble drag reduction(MBDR)and air layer drag reduction(ALDR)techniques to reduce the resistance of a 56-m Indonesian self-propelled barge(SPB).A model with the following dimensions was constructed:length L=2000 mm,breadth B=521.60 mm,and draft T=52.50 mm.The ship model was towed using standard towing tank experimental parameters.The speed was varied over the Froude number range 0.11–0.31.The air layer flow rate was varied at 80,85,and 90 standard liters per minute(SLPM)and the microbubble injection coefficient over the range 0.20–0.60.The results show that the ship model using the air layer had the highest drag reduction up to a maximum of 90%.Based on the characteristics of the SPB,which operates at low speed,the optimum air lubrication type to reduce resistance in this instance is ALDR.

Dynamic Response of Offshore Wind Turbine on 3×3 Barge Array Floating Platform under Extreme Sea Conditions

Offshore wind farm construction is nowadays state of the art in the wind power generation technology.However,deep water areas with huge amount of wind energy require innovative floating platforms to arrange and install wind turbines in order to harness wind energy and generate electricity.The conventional floating offshore wind turbine system is typically in the state of force imbalance due to the unique sway characteristics caused by the unfixed foundation and the high center of gravity of the platform.Therefore,a floating wind farm for 3×3 barge array platforms with shared mooring system is presented here to increase stability for floating platform.The NREL 5 MW wind turbine and ITI Energy barge reference model is taken as a basis for this work.Furthermore,the unsteady aerodynamic load solution model of the floating wind turbine is established considering the tip loss,hub loss and dynamic stall correction based on the blade element momentum(BEM)theory.The second development of AQWA is realized by FORTRAN programming language,and aerodynamic-hydrodynamic-Mooring coupled dynamics model is established to realize the algorithm solution of the model.Finally,the 6 degrees of freedom(DOF)dynamic response of single barge platform and barge array under extreme sea condition considering the coupling effect of wind and wave were observed and investigated in detail.The research results validate the feasibility of establishing barge array floating wind farm,and provide theoretical basis for further research on new floating wind farm.

Coupled Responses of Sewol,Twin Barges and Slings During Salvage

Korean Sewol is successfully lifted up with the strand jack system based on twin barges. During the salvage operation, two barges and Sewol encounter offshore environmental conditions of wave, current and wind. It is inevitable that the relative motions among the three bodies are coupled with the sling tensions, which may cause big dynamic loads for the lifting system. During the project engineering phase and the site operation, it is necessary to build up a simulation model that can precisely generate the coupled responses in order to define a suitable weather window and monitor risks for the salvage operation. A special method for calculating multibody coupled responses is introduced into Sewol salvage project. Each body’s hydrodynamic force and moment in multibody configuration is calculated in the way that one body is treated as freely moving in space, while other bodies are set as fixed globally.The hydrodynamic force and moment are then applied into a numerical simulation model with some calibration coefficients being inserted. These coefficients are calibrated with the model test results. The simulation model built up this way can predict coupled responses with the similar accuracy as the model test and full scale measurement,and particularly generate multibody shielding effects. Site measured responses and the responses only resulted from from the simulation keep project management simultaneously to judge risks of each salvage stage, which are important for success of Sewol salvage.

The influence of up-wave barge motion on the water resonance at a narrow gap between two rectangular barges underwaves in the sea

A three-dimensional time-domain potential flow model is developed and applied to simulate the wave resonance in a gap between two side-by-side rectangular barges. A fourth-order predict-correct method is implemented to update free surface boundary conditions. The response of an up-wave barge is predicted by solving the motion equation with the Newmark-β method. Following the validation of the developed numerical model for wave radiation and diffraction around two side-by-side barges, the influence of up-wave barge motion on the gap surfaceresonance is investigated in two different locations of the up-wave barge relative to the back-wave barge at various frequencies. The results reveal that the freely floating up-wave barge significantly influences the resonance frequency and the resonance wave amplitude. Simultaneously, the up-wave barge located in the middle of the back-wave barge leads to a reduction in the resonance wave amplitude and motion response when compared with other configurations.

Evaluating the maneuverability of a new type of self-propelled barge

A new type of self-propelled barge was designed specifically for use on the Chishui River. This paper presents experimental results of its performance from tests in water of different depths,while bearing different loads. For test purposes,one of the best self-propelled barges from the Chishui River was used as a performance reference. The comparison showed that the new design has better maneuvering performance.

Fluid Resonance Between Twin Floating Barges with Roll Motion Under Wave Action

The wave-induced fluid resonance between twin side-by-side rectangular barges coupled with the roll motion of the twin barges is investigated by both numerical simulation and physical model test.A 2D numerical wave flume,based on an open source computational fluid dynamics(CFD)package OpenFOAM,is applied for the numerical simulation.After numerical validations and convergent verifications,the characteristics of the fluid resonance in the gap between the twin rolling side-by-side barges are examined.The resonant frequency of the oscillating fluid in the gap between the twin rolling barges decreases compared with that between the twin fixed barges.Generally,the twin barges roll in the opposite directions,and their equilibrium positions lean oppositely with respect to the initial vertical direction.A physical model test is carried out for a further investigation,in which the twin barges are set oppositely leaning and fixed.From the present experimental results,a linear decrease of the resonant frequency with the increasing leaning angle is found.Combined with the numerical results,the deflection of the equilibrium positions of the twin barges is a relevant factor for the resonant frequency.Besides,the effects of the gap width and incident wave height on the fluid resonance coupled with roll motion are examined.

天鲲号绞吸挖泥船挖岩作业配套船舶技术研究

随着全球经济增长和疏浚业的扩大,大型绞吸挖泥船已成为这一领域的关键装备。文章专注于提升超大型绞吸挖泥船“天鲲号”的效能。通过分析该船在挖岩工程中的挑战,引入了“挖-运分离”的高效物流策略。为实现这一目标,建议开发一艘专门与天鲲号配套使用的开体式耙吸挖泥船。文章详细讨论了开体式耙吸挖泥船在主尺度和舱容、快速靠泊、泥舱结构和强度、疏浚系统和船舶布局等方面与天鲲号的匹配问题。提出了一个新颖的开体式耙吸挖泥船方案,能够完全满足配合天鲲号挖岩装驳和运输的需求,实现“挖-运分离”物流策略;能够开展后期扫浅挖泥作业,减少天鲲号的占用期,从而显著提升整体经济效益。

带月池驳船式浮式风力机水动力性能

参考Ideol-Floatgen相关设计,对带月池驳船式浮式风力机进行频域水动力性能研究,考虑了月池黏性阻尼的修正.首先对月池的共振模态进行分析,计算风力机在规则波下的水动力系数与不规则波下运动响应谱,并结合DNV相关规范对风力机的安全性进行了评估.结果表明,在作业工况与生存工况下,浮式风力机的动态纵倾与机舱加速度均符合安全性要求.通过对驳船式浮式风力机运动与月池共振的耦合作用的研究,发现风力机的运动会引起月池活塞共振频率的偏移与活塞共振幅值的减小,晃荡共振的频率基本不受影响,但一阶晃荡共振的幅值会增大.与无月池驳船式浮式风力机相比,月池可以降低风力机整体的运动响应,提升风力机整体的水动力性能.对浮式风力机驳船式平台的边长、月池边长与平台吃水进行参数化分析,将风力机的纵荡、垂荡、纵摇响应均方根(RMS)值与机舱加速度响应RMS值作为对比的指标,发现平台边长的增加可以有效降低风力机在作业工况与生存工况下的4项响应RMS值;月池边长的增加可以大幅降低平台生存工况下的4项响应RMS值;平台吃水的增加可以显著降低风力机在作业工况下的4项响应RMS值,并提高生存工况下的垂荡与纵摇响应RMS值.

填海造陆工程中建筑废料的绿色环保应用技术

结合某工程技术要求和限制因素,开展了建筑废料填海技术研究。通过对建筑废料的物料特性分析,提出三级台阶和低摩擦阻力型的棒条型筛分给料机和卡扣式可快速更换筛网、可调振幅振动筛组成的两级筛分工艺设施,解决了建筑废料筛分难题;研制了自带随船挖掘机的自航平板驳船,实现了建筑废料海运、卸载和转驳;研制了新型浅吃水、低净空、可升降防污帘的环保型开体驳船,实现了限高限深条件下的水上环保回填。

深水导管架滑移装船技术研究

该研究以“海基一号”导管架为例对深水导管架滑移装船进行技术研究,从设备选型布局、拖拉点设计、滑道铺设、码头强度校核、驳船系泊及驳船调载等多个方面进行技术分析,为深水导管架装船提供较为合理的滑移装船技术方案。该项技术能够指导深水导管架滑移装船设计与施工,为深水油气开发建设大型结构物装船领域提供技术基础。

整平船施工管理系统国产化研发试验及应用

自升平台式整平船施工管理系统为沉管隧道施工建设发挥了关键性的作用。通过学习和剖析原有测量与控制系统的功能和操控方法,研发新系统,并通过3个阶段技术方案实施,验证了新系统的整平精度。作为国内首次自主研发整平船施工管理系统,系统完全达到研发目标,在国内开创了整平船施工管理系统研发的先河。

基于MOSES软件的系泊下大型起重船吊装作业适用性分析

为降低大型锚泊定位起重船在不同水深区域吊装作业的安全风险,以7000 t起重船为例,采用数值模拟方法,在MOSES软件中建立起重船、吊物和系泊系统耦合分析模型,对系泊下大型起重船吊装作业工况进行模拟,结果表明,系泊吊装作业受浪向、波高、波周期、锚缆预张力和作业水深变化的影响,在实际操作中,根据作业水深采取相应的船位和预张力,可以有效地改善大型起重船系泊吊装作业的适用性。