Load on Turbine Blade Induced by Motion of Floating Platform and Design Requirement for the Platform

2007 ◽  
Author(s):  
Hideyuki Suzuki ◽  
Akira Sato
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Bending Moment ◽  
Maximum Load ◽  
Offshore Wind ◽  
Offshore Wind Energy ◽  
Fatigue Load ◽  
Design Requirement ◽  
Floating Platform

Due to the limited land area and mountainous topography, Japan is not necessarily suited for land-based wind power generation. But potential of offshore wind energy around the country is huge and has ability to supply whole electricity of the country. Development of offshore wind energy is also a promising solution for establishing sustainable society in the country. Water depth around the country generally becomes sharply deeper with distance from the shoreline and floating platform is necessary to deploy wind turbines. This paper investigates effect of motion of floating platform on the strength of turbine blade, a key issue in designing floating wind turbine, and design requirement for floating platform was discussed. Inertial load induced in the turbine blade by the motion of platform and rotation of turbine was formulated. The formulated load on the blade was verified by experiment with rotating rod on the oscillating tower. Two analysis codes, structural analysis code of turbine blade and motion analysis code of SPAR type floating platform, were developed. The effect of platform motion on the bending moment induced in the blade was investigated using the codes and design requirements for the platform were investigated from a viewpoint of maximum load and fatigue load. From a series of analysis on 5MW wind turbine showed that maximum load on blade is increased by 10% for pitching with amplitude of 5degrees but sectional modulus must be increased by 50% for fatigue. It is concluded that the increase of maximum load on the blade due to the motion of floating platform is not serious but fatigue load can be significant. Design requirement for the motion of floating platform will be that the amplitude of pitching motion should be less than a few degrees so that the land-based wind turbine can be installed on the floating platform with minimum modification.

Research Development and Key Technical on Floating Foundation for Offshore Wind Turbines

2012 ◽  
Vol 446-449 ◽  
pp. 1014-1019 ◽  
Author(s):  
Ruo Yu Zhang ◽  
Chao He Chen ◽  
You Gang Tang ◽  
Xiao Yan Huang
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Water Area ◽  
Offshore Wind ◽  
Offshore Wind Energy ◽  
Floating Structure ◽  
Floating Structures ◽  
Floating Foundation ◽  
Set Up ◽  
Sea Area

The water area in which water depth is deeper than 50m has special advantage in wind turbine generation, because there are the stable wind speed and small Wind-shear. In such sea area, the offshore wind energy generating equipments should be set up on floating foundation structure. Therefore, it is of great significance to study the floating foundation structures that are available for offshore wind energy generation for the industrialization of the offshore wind power generation. In this paper, the basic type and working principles are reviewed for some novel floating structures developed in recent year. In addition, some key dynamical problems and risk factors of the floating structure are systemically analyzed for working load caused by turbine running and sea environment loads of floating structure. The results are valuable for designing the floating structures of wind turbine generation.

Advanced Concept Offshore Wind Turbine Development

2014 ◽  
Vol 18 (5) ◽  
pp. 728-735 ◽  
Author(s):  
Abdollah A. Afjeh ◽  
◽  
Brett Andersen ◽  
Jin Woo Lee ◽  
Mahdi Norouzi ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Cost Savings ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Wind Energy ◽  
Offshore Wind Turbines ◽  
Floating Foundation ◽  
The Cost

Development of novel offshore wind turbine designs and technologies are necessary to reduce the cost of offshore wind energy since offshore wind turbines need to withstand ice and waves in addition to wind, a markedly different environment from their onshore counterparts. This paper focuses on major design challenges of offshore wind turbines and offers an advanced concept wind turbine that can significantly reduce the cost of offshore wind energy as an alternative to the current popular designs. The design consists of a two-blade, downwind rotor configuration fitted to a fixed bottom or floating foundation. Preliminary results indicate that cost savings of nearly 25% are possible compared with the conventional upwind wind turbine designs.

scholarly journals Analysis of the Effect of a Series of Back Twist Blade Configurations for an Active Pitch-To-Stall Floating Offshore Wind Turbine

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Dawn Ward ◽  
Maurizio Collu ◽  
Joy Sumner
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Twist Angle ◽  
Bending Moment ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Power Performance ◽  
Floating Platform ◽  
Initiation Point ◽  
Negative Damping

Abstract For a turbine mounted on a floating platform, extreme induced loads can be increased by up to 1.6 times those experienced by a turbine situated on a fixed base. If these loads cannot be reduced, towers must be strengthened which will result in increased costs and weight. These tower loads would be additionally exasperated for a pitch-to-feather controlled turbine by a phenomenon generally referred to as “negative damping,” if it were not avoided. Preventing negative damping from occurring on a pitch-to-feather controlled floating platform negatively affects rotor speed control and regulated power performance. However, minimizing the blade bending moment response can result in a reduction in the tower fore-aft moment response, which can increase the tower life. A variable-speed, variable pitch-to-stall (VSVP-S) floating semi-submersible wind turbine, which does not suffer from the negative damping and hence provides a more regulated power output, is presented. This incorporates a back twist blade profile such that the blade twist, starting at the root, initially twists toward stall and, at some pre-determined “initiation” point, changes direction to twist back toward feather until the tip. Wind frequency weighting was applied to the tower axial fatigue life trends of different blade profiles and a preferred blade back twist profile was identified. This had a back twist angle of −3 deg and started at 87.5% along the blade length and achieved a 5.1% increase in the tower fatigue life.

A Review of Floating Platform Concepts for Offshore Wind Energy Generation

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
K. P. Thiagarajan ◽  
H. J. Dagher
Keyword(s):  
Wind Energy ◽  
Special Section ◽  
Clean Energy ◽  
Energy Generation ◽  
Structure Design ◽  
Offshore Wind ◽  
Offshore Wind Energy ◽  
Floating Platform ◽  
Offshore Structure ◽  
Wind Energy Generation

Literature relating to offshore wind energy generation is produced at a significant rate as research efforts are diverted to the emerging area of future clean energy. This paper presents an overview of recent research in the specific area of floating offshore structure design for wind energy. Earlier literature has broadly grouped these platforms into three categories based on their source of stability: (1) ballast stabilized (low center of gravity), e.g., spar, (2) mooring stabilized, e.g., tension leg platform, and (3) buoyancy or water-plane stabilized, e.g., semisubmersible. These concepts were modifications of similar structures used in the offshore oil and gas industry. Recent papers have presented further improvements to these designs, including active ballasting and control systems. These are examined for stability and global performance behavior and ease of operability and maintenance. The paper also attempts to examine efforts to bring such concepts to fruition. This paper sets the stage for other papers in the Special Session on University of Maine/DeepCWind Consortium within the Offshore Renewable Energy Symposium at OMAE 2012, which are archived in the special section of the Journal of Offshore Mechanics and Arctic Engineering.

scholarly journals Structural Modeling and Failure Assessment of Spar-Type Substructure for 5 MW Floating Offshore Wind Turbine under Extreme Conditions in the East Sea

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6571
Author(s):  
Kwangtae Ha ◽  
Jun-Bae Kim ◽  
Youngjae Yu ◽  
Hyoung-Seock Seo
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Three Dimensional ◽  
Offshore Wind ◽  
East Sea ◽  
Offshore Wind Turbine ◽  
Fe Model ◽  
Offshore Wind Energy ◽  
Floating Offshore Wind Turbine ◽  
Load Analysis

Not only the driving for offshore wind energy capacity of 12 GW by Korea’s Renewable Energy 2030 plan but also the need for the rejuvenation of existing world-class shipbuilders’ infrastructures is drawing much attention to offshore wind energy in Korea, especially to the diverse substructures. Considering the deep-sea environment in the East Sea, this paper presents detailed modeling and analysis of spar-type substructure for a 5 MW floating offshore wind turbine (FOWT). This process uses a fully coupled integrated load analysis, which was carried out using FAST, a widely used integrated load analysis software developed by NREL, coupled with an in-house hydrodynamic code (UOU code). The environmental design loads were calculated from data recorded over three years at the Ulsan Marine buoy point according to the ABS and DNVGL standards. The total 12 maximum cases from DLC 6.1 were selected to evaluate the structural integrity of the spar-type substructure under the three co-directional conditions (45°, 135°, and 315°) of wind and wave. A three-dimensional (3D) structural finite element (FE) model incorporating the wind turbine tower and floating structure bolted joint connection was constructed in FEGate (pre/post-structural analysis module based on MSC NASTRAN for ship and offshore structures). The FEM analysis applied the external loads such as the structural loads due to the inertial acceleration, buoyancy, and gravity, and the environmental loads due to the wind, wave, and current. The three-dimensional FE analysis results from the MSC Nastran software showed that the designed spar-type substructure had enough strength to endure the extreme limitation in the East Sea based on the von Mises criteria. The current process of this study would be applicable to the other substructures such as the submersible type.

scholarly journals Design of an Offshore Three-Bladed Vertical Axis Wind Turbine for Wind Tunnel Experiments

2017 ◽  
Author(s):  
Sukanta Roy ◽  
Hubert Branger ◽  
Christopher Luneau ◽  
Denis Bourras ◽  
Benoit Paillard
Keyword(s):  
Wind Tunnel ◽  
Wind Energy ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Energy Market ◽  
Offshore Wind Energy ◽  
Vertical Axis Wind Turbine ◽  
Wind Tunnel Experiments ◽  
Vertical Axis Wind Turbines

The rapid shrinkage of fossil fuel sources and contrary fast-growing energy needs of social, industrial and technological enhancements, necessitate the need of different approaches to exploit the various renewable energy sources. Among the several technological alternatives, wind energy is one of the most emerging prospective because of its renewable, sustainable and environment friendly nature, especially at its offshore locations. The recent growth of the offshore wind energy market has significantly increased the technological importance of the offshore vertical axis wind turbines, both as floating or fixed installations. Particularly, the class of lift-driven vertical axis wind turbines is very promising; however, the existing design and technology is not competent enough to meet the global need of offshore wind energy. In this context, the project AEROPITCH co-investigated by EOLFI, CORETI and IRPHE aims at the development of a robust and sophisticated offshore vertical axis wind turbine, which would bring decisive competitive advantage in the offshore wind energy market. In this paper, simulations have been performed on the various airfoils of NACA 4-series, 5-series and Selig profiles at different chord Reynolds numbers of 60000, 100000 and 140000 using double multiple streamtube model with tip loss correction. Based on the power coefficient, the best suitable airfoil S1046 has been selected for a 3-bladed vertical axis wind turbine. Besides the blade profile, the turbine design parameters such as aspect ratio and solidity ratio have also been investigated by varying the diameter and chord of the blade. Further, a series of wind tunnel experiments will be performed on the developed wind turbine, and the implementation of active pitch control in the developed turbine will be investigated in future research.

scholarly journals A Comparative Study on the Dynamic Response of Three Semisubmersible Floating Offshore Wind Turbines

2019 ◽  
Author(s):  
Wei Shi ◽  
Lixian Zhang ◽  
Dezhi Ning ◽  
Zhiyu Jiang ◽  
Constantine Michailides ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Wind Energy ◽  
Comparative Study ◽  
Wind Turbine ◽  
Offshore Wind ◽  
Offshore Wind Energy ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbines ◽  
Floating System ◽  
Design Tradeoffs

Abstract Currently, there is a great interest to globally develop offshore wind energy due to the greenhouse effect and energy crisis. Great efforts have been devoted to develop reliable floating offshore wind energy technology to exploit the wind energy resources in deep seas. This paper presents a comparative study of the dynamic response of three different semisubmersible floating wind turbine structures. All the three platforms support the same 5MW wind turbine. The platforms examined are: a V-shaped Semi, an OC4-DeepCwind Semi and a Braceless Semi at 200 m water depth. A dynamic analysis is carried out in order to calculate and compare the performance of these platforms. The comparison is made on the rigid body motions of the semisubmersible platform and tensions of the mooring lines. The presented comparison is based on statistical values and spectra of the time series of the examined response quantities. Coupling effects are more significant for the V-shaped Semi platform. The V-shaped Semi and the Braceless Semi show a more rational motion response under the investigated load cases. The results of this analysis may help to resolve the fundamental design tradeoffs between among different floating system concepts.

Fatigue Analysis of a 12-MW Wind Turbine Blade

2018 ◽  
Author(s):  
Hyeonjeong Ahn ◽  
Hyunkyoung Shin
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Fatigue Analysis ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Fatigue Load ◽  
Wind Turbine Blades ◽  
Design Life ◽  
Large Wind

In 2017, the MHI Vestas released a 9.5-MW offshore wind turbine. It is also actively researching and developing a 10-MW offshore wind turbine. As the capacity of a wind turbine increases, the sizes of all its system components, including length and weight, correspondingly increase. Consequently, as a wind turbine becomes larger, it becomes necessary to analyze the fatigue load applied to its entire system. The first reason for such an analysis is to achieve a safe but not overly designed large wind turbine. Second, most wind turbine accidents involve aging turbines and are related to fatigue analysis. Accordingly, the purpose of fatigue analysis is to safely design a wind turbine that sustains repeated loads within its design life. In this study, the blades and loads for the fatigue analysis of a 12-MW floating offshore wind turbine are calculated based on the National Renewable Energy Laboratory (NREL) 5-MW wind turbine blades. The calculated loads are applied to the Markov matrix through a preprocessing, such as the cycle counting method. Finally, the equivalent fatigue load is estimated based on both mean and range. In this study, only the equivalent fatigue load on the turbine blade is calculated. However, if fatigue analysis is to be performed for all parts using equivalent loads, it is possible to design the wind turbine to fully withstand such loads throughout its design life, and prevent the overdesign of each part as well.

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