• Title/Summary/Keyword: 부유식 해상 풍력발전기

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Dynamic Constrained Force of Tower Top and Rotor Shaft of Floating Wind Turbine (부유식 해상 풍력 발전기의 Tower Top 및 Rotor Shaft에 작용하는 동적 하중 계산)

  • Ku, Nam-Kug;Roh, Myung-Il;Lee, Kyu-Yeul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.5
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    • pp.455-463
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    • 2012
  • In this study, we calculate dynamic constrained force of tower top and blade root of a floating offshore wind turbine. The floating offshore wind turbine is multibody system which consists of a floating platform, a tower, a nacelle, and a hub and three blades. All of these parts are regarded as a rigid body with six degree-of-freedom(DOF). The platform and the tower are connected with fixed joint, and the tower, the nacelle, and the hub are successively connected with revolute joint. The hub and three blades are connected with fixed joint. The recursive formulation is adopted for constructing the equations of motion for the floating wind turbine. The non-linear hydrostatic force, the linear hydrodynamic force, the aerodynamic force, the mooring force, and gravitational forces are considered as external forces. The dynamic load at the tower top, rotor shaft, and blade root of the floating wind turbine are simulated in time domain by solving the equations of motion numerically. From the simulation results, the mutual effects of the dynamic response between the each part of the floating wind turbine are discussed and can be used as input data for the structural analysis of the floating offshore wind turbine.

Dynamic Behavior Analysis of Floating Offshore Wind Turbine Including Flexible Effects of Tower and Blade (타워와 블레이드의 탄성효과를 고려한 부유식 해상풍력발전기의 동적거동해석)

  • Jung, Hye-Young;Sohn, Jeong-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.8
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    • pp.905-911
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    • 2012
  • To establish a floating offshore wind turbine simulation model, a tension leg platform is added to an onshore wind turbine. The wind load is calculated by using meteorological administration data and a power law that defines the wind velocity according to the height from the sea surface. The wind load is applied to the blade and wind tower at a regular distance. The relative Morison equation is employed to generate the wave load. The rated rotor speed (18 rpm) is applied to the hub as a motion. The dynamic behavior of a 2-MW floating offshore wind turbine subjected to the wave excitation and wind load is analyzed. The flexible effects of the wind tower and the blade are analyzed. The flexible model of the wind tower and blade is established to examine the natural frequency of the TLP-type offshore wind turbine. To study the effect of the flexible tower and blade on the floating offshore wind turbine, we modeled the flexible tower model and flexible tower-blade model and compared it with a rigid model.

A Frequency Domain Motion Response Analysis of Substructure of Floating Offshore Wind Turbine with Varying Trim (부유식 해상풍력발전기 하부구조물의 종경사각에 따른 주파수 영역 운동응답 분석)

  • In-hyuk Nam;Young-Myung Choi;Ikseung Han;Chaeog Lim;Jinuk Kim;Sung-chul Shin
    • Journal of Navigation and Port Research
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    • v.48 no.3
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    • pp.155-163
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    • 2024
  • As the demand for reducing carbon emissions increases, efforts to reduce the usage of fossil fuels and research on renewable energy are also increasing. Among the various renewable energy harvesting techniques, the floating offshore wind turbine has several advantages. Compared to other technologies, it has fewer installation limitations due to interference with human activity. Additionally, a large wind turbine farm can be constructed in the open ocean. Therefore, it is important to conduct motion analysis of floating offshore wind turbines in waves during the initial stage of conceptual design. In this study, a frequency motion analysis was conducted on a semi-submersible type floating offshore wind turbine. The analysis focused on the effects of varying trim on the motion characteristics. Specifically, motion response analysis was performed on heave, roll, and pitch. Natural period analysis confirmed that changing the trim angle did not significantly affect the heave and pitch motions, but it did have a regular impact on the roll motion.

Structural Analysis of Floating Offshore Wind Turbine Tower Based on Flexible Multibody Dynamics (탄성 다물체계 동역학을 기반으로 한 부유식 해상 풍력 발전기 타워의 구조 해석)

  • Park, Kwang-Phil;Cha, Ju-Hwan;Ku, Namkug;Jo, A-Ra;Lee, Kyu-Yeul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.12
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    • pp.1489-1495
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    • 2012
  • In this study, we perform the structural analysis of a floating offshore wind turbine tower by considering the dynamic response of the floating platform. A multibody system consisting of three blades, a hub, a nacelle, the platform, and the tower is used to model the floating wind turbine. The blades and the tower are modeled as flexible bodies using three-dimensional beam elements. The aerodynamic force on the blades is calculated by the Blade Element Momentum (BEM) theory with hub rotation. The hydrostatic, hydrodynamic, and mooring forces are considered for the platform. The structural dynamic responses of the tower are simulated by numerically solving the equations of motion. From the simulation results, the time history of the internal forces at the nodes, such as the bending moment and stress, are obtained. In conclusion, the internal forces are compared with those obtained from static analysis to assess the effects of wave loads on the structural stability of the tower.

Unsteady Aerodynamic Characteristics of Floating Offshore Wind Turbine According to Wave Height and Wave Angular Frequency (해상용 부유식 풍력 발전기의 파고와 파주기에 따른 비정상 공력 특성 연구)

  • Jeon, Minu;Kim, Hogeon;Lee, Soogab
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.184.1-184.1
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    • 2010
  • Floating wind turbines have been suggested as a feasible solution for going further offshore into deeper waters. However, floating platforms cause additional unsteady motions induced by wind and wave conditions, so that it is difficult to predict annual energy output of wind turbines by using conventional power prediction method. That is because sectional inflow condition on a rotor plane is varied by unsteady motion of floating platforms. Therefore, aerodynamic simulation using Vortex Lattice Method(VLM) were used to investigate the influence of motion on the aerodynamic performance of a floating offshore wind turbine. Simulation with individual motion of offshore platform were compared to the case of onshore platform and carried out according to the wave height and the wave angular frequency.

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A Study on the Optimal Shape Design of a Floating Offshore Wind Turbine (부유식 해상 풍력 발전기의 최적 형상 설계에 관한 연구)

  • Park, Jeong-Hoon;Shin, Hyunkyoung
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.3
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    • pp.171-179
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    • 2015
  • Usually, in case of wind turbines on land, there are a lot of constraints for installation such as the insufficient installation space and noise pollution. On March 11, 2011, a nuclear leakage accident occurred due to the tsunami caused by the earthquake in Japan and then there have been a rapidly growing interest in floating offshore wind turbines. In this study, an optimization of the substructure of a semi-submersible type floating offshore wind turbine was made. Design variables were set and design alternatives were fixed. UOU-FAST was used for motion analysis in combined environmental conditions of waves and wind. Response Amplitude Operators(RAOs) were compared between the design alternatives.

Analysis of Dynamic Behavior of Floating Offshore Wind Turbine System (해상 부유식 풍력 타워의 동적거동해석)

  • Jang, Jin-Seok;Sohn, Jeong-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.1
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    • pp.77-83
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    • 2011
  • In this study, the dynamic modeling of floating offshore wind turbine system is reported and the dynamic behavior of the platform for the offshore wind turbine system is analyzed. The modeling of the wind load for a floating offshore wind turbine tower is based on the vertical profile of wind speed. The relative Morison equation is employed to obtain the wave load. ADAMS is used to carry out the dynamic analysis of the floating system that should withstand waves and the wind load. Computer simulations for four types of tension leg platforms are performed, and the simulation results for the platforms are compared with each other.

Arrangement Design and Performance Evaluation for Multiple Wind Turbines of 10MW Class Floating Wave-Offshore Wind Hybrid Power Generation System (10MW급 부유식 파력-해상풍력 연계형 발전 시스템의 다수 풍력터빈 배치 설계 및 성능 평가)

  • Park, Sewan;Kim, Kyong-Hwan;Lee, Kang-Su;Park, Yeon-Seok;Oh, Hyunseok;Shin, Hyungki;Hong, Keyyong
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.18 no.2
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    • pp.123-132
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    • 2015
  • In this study, an arrangement design process for multiple wind turbines, placed on the 10MW class floating wave-offshore wind hybrid power generation system, was presented, and the aerodynamic performance was evaluated by using a computational fluid dynamics. An arrangement design, which produces a maximum power in the site wind field, was found by using a commercial program, WindPRO, based on a blade element momentum theory, then the effect of wake interference on the system between multiple wind turbines was studied and evaluated by using ANSYS CFX.

Resonance Analysis According to Initial Tower Design for Floating Offshore Wind Turbine (부유식 해상풍력발전기 타워의 초기 형상에 따른 공진 해석)

  • Kim, Junbae;Shin, Hyunkyoung
    • Journal of Wind Energy
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    • v.9 no.4
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    • pp.57-64
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    • 2018
  • To maximize power generation and reduce the construction cost of a commercial utility-grade wind turbine, the size of the wind turbine should be large. The initial design of the 12 MW University of Ulsan(UOU) Floating Offshore Wind Turbine(FOWT) was carried out based on the 5 MW National Renewable Energy Laboratory(NREL) offshore wind turbine model. The existing 5 MW NREL offshore wind turbines have been expanded to 12 MW UOU FOWT using the geometric law of similarity and then redesigned for each factor. The resonance of the tower is the most important dynamic responses of a wind turbine, and it should be designed by avoiding resonance due to cyclic load during turbine operations. The natural frequency of the tower needs to avoid being within the frequency range corresponding to the rotational speed of the blades, 1P, and the blade passing frequency, 3P. To avoid resonance, vibration can be reduced by modifying the stiffness or mass. The direct expansion of the 5 MW wind turbine support structure caused a resonance problem with the tower of the 12 MW FOWT and the tower length and diameter was adjusted to avoid a match of the first natural frequency and 3P excitation of the tower.