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Influence of Surface Ice Roughness on the Aerodynamic Performance of Wind Turbines
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作者 Xin Guan Mingyang Li +2 位作者 Shiwei Wu Yuqi Xie Yongpeng Sun 《Fluid Dynamics & Materials Processing》 EI 2024年第9期2029-2043,共15页
The focus of this research was on the equivalent particle roughness height correction required to account for the presence of ice when determining the performances of wind turbines.In particular,two icing processes(fr... The focus of this research was on the equivalent particle roughness height correction required to account for the presence of ice when determining the performances of wind turbines.In particular,two icing processes(frost ice and clear ice)were examined by combining the FENSAP-ICE and FLUENT analysis tools.The ice type on the blade surfaces was predicted by using a multi-time step method.Accordingly,the influence of variations in icing shape and ice surface roughness on the aerodynamic performance of blades during frost ice formation or clear ice formation was investigated.The results indicate that differences in blade surface roughness and heat flux lead to disparities in both ice formation rate and shape between frost ice and clear ice.Clear ice has a greater impact on aerodynamics compared to frost ice,while frost ice is significantly influenced by the roughness of its icy surface. 展开更多
关键词 Wind turbine icing blade surface roughness aerodynamic characteristics AIRFOIL
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Influence of Blade Number on the Performance of Hydraulic Turbines in the Transition Stage
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作者 Fengxia Shi Guangbiao Zhao +1 位作者 Yucai Tang Dedong Maand Xiangyun Shi 《Fluid Dynamics & Materials Processing》 EI 2024年第11期2617-2636,共20页
To analyze the effect of blade number on the performance of hydraulic turbines during the transient stage in which theflow rate is not constant,six hydraulic turbines with different blade numbers are considered.The ins... To analyze the effect of blade number on the performance of hydraulic turbines during the transient stage in which theflow rate is not constant,six hydraulic turbines with different blade numbers are considered.The instantaneous hydraulic performance of the turbine and the pressure pulsation acting on the impeller are investigated numerically by using the ANSYS CFX software.The ensuing results are compared with the outcomes of experimental tests.It is shown that thefluctuation range of the pressure coefficient increases with time,but the corresponding range for the transient hydraulic efficiency decreases gradually when theflow velocity transits to larger values.During the transition to smallflow velocity,thefluctuation range of the pressure coefficient gradually decreases as time passes,but the correspondingfluctuation range of its transient hydraulic efficiency gradually becomes larger.Thefluctuation range in the Z9 case is small during the transition.The main frequency of transient hydraulic efficiency pulsation is equal to the blade frequency.At the main frequency,Z7 has the largest amplitude of the hydraulic efficiency pulsation,Z10 has the smallest amplitude,and the difference between Z7 and Z9 is limited.As the number of blades grows,the pressure pulsation during the transition process gradually decreases,but the pressure pulsation of Z10 at the volute tongue is larger.In the steady state,Z9 has the highest efficiency and in the transient stage,the pressure coefficientfluctuation range is small.Accordingly,for the hydraulic turbine Z9,the performance is optimal. 展开更多
关键词 Hydraulic turbine blade number transient process pressurefluctuation transient hydraulic performance
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Influence of the Ambient Temperature on the Efficiency of Gas Turbines
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作者 Mahdi Goucem 《Fluid Dynamics & Materials Processing》 EI 2024年第10期2265-2279,共15页
In hot and arid regions like the Saharan area,effective methods for cooling and humidifying intake air are essential.This study explores the utilization of a water trickle cooler as a promising solution to meet this o... In hot and arid regions like the Saharan area,effective methods for cooling and humidifying intake air are essential.This study explores the utilization of a water trickle cooler as a promising solution to meet this objective.In particular,the HASSI MESSAOUD area is considered as a testbed.The water trickle cooler is chosen for its adaptability to arid conditions.Modeling results demonstrate its effectiveness in conditioning air before it enters the compressor.The cooling system achieves a significant temperature reduction of 6 to 8 degrees Celsius,enhancing mass flow rate dynamics by 3 percent compared to standard cases without cooling.Moreover,the cooling system contributes to a remarkable 10 percent reduction in power consumption of gas turbines and a notable 10 percent increase in turbine efficiency.These findings highlight the potential of water trickle coolers in improving the performance and efficiency of gas turbine systems in hot and dry climates. 展开更多
关键词 Gas turbine inlet COOLING computational fluid dynamics(CFD) POWER thermal efficiency
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Study on the Relationship between Structural Aspects and Aerodynamic Characteristics of Archimedes Spiral Wind Turbines
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作者 Yuanjun Dai Zetao Deng +2 位作者 Baohua Li Lei Zhong Jianping Wang 《Fluid Dynamics & Materials Processing》 EI 2024年第7期1517-1537,共21页
A combined experimental and numerical research study is conducted to investigate the complex relationship between the structure and the aerodynamic performances of an Archimedes spiral wind turbine(ASWT).Two ASWTs are... A combined experimental and numerical research study is conducted to investigate the complex relationship between the structure and the aerodynamic performances of an Archimedes spiral wind turbine(ASWT).Two ASWTs are considered,a prototypical version and an improved version.It is shown that the latter achieves the best aerodynamic performance when the spread angles at the three sets of blades areα_(1)=30°,α_(2)=55°,α3=60°,respectively and the blade thickness is 4 mm.For a velocity V=10 m/s,a tip speed ratio(TSR)=1.58 and 2,the maximum CP values are 0.223 and 0.263 for the prototypical ASWT and improved ASWT,respectively,and the maximum C_(P) enhancement is 17.93%.For V=10 m/s and TSR=2,the CP values of the prototypical ASWT and improved ASWT are 0.225 and 0.263,respectively,with an aerodynamic performance enhancement of 16.88%.Through mutual verification of the test outcomes and numerical results,it is concluded that the proposed approach can effectively lead to aerodynamic performance improvement. 展开更多
关键词 Archimedes spiral wind turbine aerodynamic performance numerical calculation
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Impact of Blade-Flapping Vibration on Aerodynamic Characteristics of Wind Turbines under Yaw Conditions
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作者 Shaokun Liu Zhiying Gao +2 位作者 Rina Su Mengmeng Yan Jianwen Wang 《Energy Engineering》 EI 2024年第8期2213-2229,共17页
Although the aerodynamic loading of wind turbine blades under various conditions has been widely studied,the radial distribution of load along the blade under various yaw conditions and with blade flapping phenomena i... Although the aerodynamic loading of wind turbine blades under various conditions has been widely studied,the radial distribution of load along the blade under various yaw conditions and with blade flapping phenomena is poorly understood.This study aims to investigate the effects of second-order flapwise vibration on the mean and fluctuation characteristics of the torque and axial thrust of wind turbines under yaw conditions using computational fluid dynamics(CFD).In the CFD model,the blades are segmented radially to comprehensively analyze the distribution patterns of torque,axial load,and tangential load.The following results are obtained.(i)After applying flapwise vibration,the torque and axial thrust of wind turbines decrease in relation to those of the rigid model,with significantly increased fluctuations.(ii)Flapwise vibration causes the blades to reciprocate along the axial direction,altering the local angle of attack and velocity of the blades relative to the incoming wind flow.This results in the contraction of the torque region from a circular shape to a complex“gear”shape,which is accompanied by evident oscillations.(iii)Compared to the tangential load,the axial load on the blades is more sensitive to flapwise vibration although both exhibit significantly enhanced fluctuations.This study not only reveals the impact of flapwise vibration on wind turbine blade performance,including the reduction of torque and axial thrust and increased operational fluctuations,but also clarifies the radial distribution patterns of blade aerodynamic characteristics,which is of great significance for optimizing wind turbine blade design and reducing fatigue risks. 展开更多
关键词 Wind turbine CFD numerical simulation aerodynamic characteristics yaw flapping vibration
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Desired Dynamic Equation for Primary Frequency Modulation Control of Gas Turbines
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作者 Aimin Gao Xiaobo Cui +2 位作者 Guoqiang Yu Jianjun Shu Tianhai Zhang 《Energy Engineering》 EI 2024年第5期1347-1361,共15页
Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency cont... Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid.However,there are some control difficulties in the primary frequency modulation control of gas turbines,such as the coupling effect of the fuel control loop and speed control loop,slow tracking speed,and so on.To relieve the abovementioned difficulties,a control strategy based on the desired dynamic equation proportional integral(DDE-PI)is proposed in this paper.Based on the parameter stability region,a parameter tuning procedure is summarized.Simulation is carried out to address the ease of use and simplicity of the proposed tuning method.Finally,DDE-PI is applied to the primary frequency modulation system of an MS6001B heavy-duty gas turbine.The simulation results indicate that the gas turbine with the proposed strategy can obtain the best control performance with a strong ability to deal with system uncertainties.The proposed method shows good engineering application potential. 展开更多
关键词 Gas turbine primary frequency modulation(PFM) desired dynamic equation(DDE) proportion-integral(PI)
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Aero-Hydrodynamic Coupled Dynamic Characteristics of Semi-Submersible Floating Offshore Wind Turbines Under Inflow Turbulence 被引量:2
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作者 JIANG Hai-rui BAI Xing-lan Murilo A.VAZ 《China Ocean Engineering》 SCIE EI CSCD 2023年第4期660-672,共13页
In this study,the frequency characteristics of the turbulent wind and the effects of wind-wave coupling on the low-and high-frequency responses of semi-submersible floating offshore wind turbines(FOWT)are investigated... In this study,the frequency characteristics of the turbulent wind and the effects of wind-wave coupling on the low-and high-frequency responses of semi-submersible floating offshore wind turbines(FOWT)are investigated.Various wave load components,such as first-order wave loads,combined first-and second-order difference-frequency wave loads,combined first-and second-order sum-frequency wave loads,and first-and complete second-order wave loads are taken into consideration,while different turbulent environments are considered in aerodynamic loads.The com-parison is based on time histories and frequency spectra of platform motions and structural load responses and statistical values.The findings indicate that the second-order difference-frequency wave loads will significantly increase the natural frequency of low-frequency motion in the responses of the platform motion and structure load of the semi-submersible platform,which will cause structural fatigue damage.Under the action of turbulent wind,the influences of second-order wave loads on the platform motion and structural load response cannot be ignored,especially under extreme sea conditions.Therefore,in order to evaluate the dynamic responses of semi-submersible FOWT more accurately,the actual environment should be simulated more realistically. 展开更多
关键词 turbulence characteristics floating offshore wind turbines second-order hydrodynamic loads low-and high-frequency responses aero-hydrodynamic coupling
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Centrifuge tests for seismic response of single pile foundation supported wind turbines in sand influenced by earthquake history 被引量:2
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作者 Wang Yubing Zhang Zhongchang +1 位作者 Wu Xiaofeng Zhu Bin 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第3期623-636,共14页
This paper reports on two sets of centrifuge model tests of wind turbines in dry sand and saturated sand subjected to earthquake sequences.The wind turbine system is composed of a single pile foundation and a wind tur... This paper reports on two sets of centrifuge model tests of wind turbines in dry sand and saturated sand subjected to earthquake sequences.The wind turbine system is composed of a single pile foundation and a wind turbine.All tests were applied with liquefaction experiments and analysis projects(LEAP)waves to simplify the analysis.The objectives of the tests are to investigate:(1)the influence of earthquake history on the seismic response of wind turbines;(2)the influence of earthquake history on the dynamic pile-soil interaction;and(3)the influence of two different foundation types on the seismic response of wind turbines.The tests indicated that earthquake history has a significant influence on the natural frequency of the pile and the soil around the pile in the saturated sand,but has no obvious influence on the dry sand.The shear modulus of the soil and the acceleration amplification factor of the pile top in both tests increased and the maximum bending moment envelope of the single pile foundation shrunk.The stiffness of the p-y curve in saturated sand was increased by the earthquake history,while that in dry sand was not significantly affected. 展开更多
关键词 earthquake history effect wind turbine pile bending moment dry and saturated sand ground dynamic p-y curves
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Sediment Erosion on Pelton Turbines:A Review 被引量:1
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作者 Xinfeng Ge Jie Sun +8 位作者 Dongdong Chu Juan Liu Ye Zhou Hui Zhang Lei Zhang Huixiang Chen Kan Kan Maxime Binama Yuan Zheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第3期36-62,共27页
The Pelton turbine has been widely used to develop high-head water resources with sediments because of its advantages in life cycle costs.When a flood or monsoon season occurs,the sediment concentration in the river i... The Pelton turbine has been widely used to develop high-head water resources with sediments because of its advantages in life cycle costs.When a flood or monsoon season occurs,the sediment concentration in the river increases suddenly,causing severe erosion to the nozzle,needle,and runner of Pelton turbines.After decades of development,researchers have developed practical engineering experience to reduce the sediment concentration of the flow through the turbine and ensure the safety and efficiency of power generation.Research on the mechanism of sediment erosion,development of anti-erosion materials,and establishment of erosion prediction models have attracted scholarly interest in recent years.Extensive research has been conducted to determine a complete and valuable syndication erosion model.However,owing to the complexity of the flow and wear mechanisms,the influence of specific parameters of erosion and the syndication effect is still difficult to determine.Computational fluid dynamics and erosion monitoring technology have also been evaluated and applied.This paper presents a comprehensive review of the erosion of Pelton turbines,some of the latest technical methods,and possible future development directions. 展开更多
关键词 Pelton turbine Sediment erosion Sediment erosion mechanism CFD The experimental method
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Hydrodynamic Characteristics of Three-Bucket Jacket Foundation for Offshore Wind Turbines During the Lowering Process 被引量:1
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作者 ZHANG Pu-yang QI Xin +3 位作者 WEI Yu-mo ZHANG Sheng-wei LE Cong-huan DING Hong-yan 《China Ocean Engineering》 SCIE EI CSCD 2023年第1期73-84,共12页
The three-bucket jacket foundation is a new type of foundation for offshore wind turbine that has the advantages of fast construction speed and suitability for deep water. The study of the hoisting and launching proce... The three-bucket jacket foundation is a new type of foundation for offshore wind turbine that has the advantages of fast construction speed and suitability for deep water. The study of the hoisting and launching process is of great significance to ensure construction safety in actual projects. In this paper, a new launching technology is proposed that is based on the foundation of the three-bucket jacket for offshore wind turbine. A complete time domain simulation of the launching process of three-bucket jacket foundation is carried out by a theoretical analysis combined with hydrodynamic software Moses. At the same time, the effects of different initial air storage and sea conditions on the motion response of the structure and the hoisting cable tension are studied. The results show that the motion response of the structure is the highest when it is lowered to 1.5 times the bucket height. The natural period of each degree of freedom of the structure increases with the increase of the lowering depth. The structural motion response and the hoisting cable tension vary greatly in the early phases of Stages Ⅰ and Ⅲ, smaller in Stage Ⅱ, and gradually stabilize in the middle and late phases of Stage Ⅲ. 展开更多
关键词 three-bucket jacket foundation time domain simulation hoisting construction motion response offshore wind turbine
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Evaluating effectiveness of multiple tuned mass dampers for vibration control of jacket offshore wind turbines under onshore and seafloor earthquakes
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作者 Pan Zuxing Liu Yingzhou +4 位作者 Wang Wenhua Li Xin Zhao Shengxiao Jiang Zhenqiang Shang Jin 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第4期1045-1063,共19页
The dynamic characteristics and structural responses of operation and grid loss offshore wind turbines(OWTs)under onshore and seafloor earthquakes are analyzed based on the established coupled seismic analysis model.I... The dynamic characteristics and structural responses of operation and grid loss offshore wind turbines(OWTs)under onshore and seafloor earthquakes are analyzed based on the established coupled seismic analysis model.In addition to the remarkable influence of the rotor system on the responses of the operation OWT under earthquakes,interactions among the natural modes of the grid loss OWT in the fore-aft and side-to-side directions are revealed.By comparing with the onshore earthquakes,the more significant differences of structural response are observed under the selected seafloor earthquakes,due to the longer duration and more abundant energy distribution around the natural frequencies of OWT.Concurrently,a multiple tuned mass damper(MTMD)is designed and applied to the operation and grid loss OWTs.Then,the comparisons of the mitigation effects under onshore and seafloor ground motions are carried out,and the necessity of applying seafloor ground motions to OWTs are proved.Moreover,in comparison to the operation OWT,more effective reductions are observed for the grid loss OWT under onshore and seafloor earthquakes using the designed MTMD.Therefore,the combined shutdown procedures and MTMD vibration control strategy is suggested for OWTs under earthquakes. 展开更多
关键词 offshore wind turbine EARTHQUAKE vibration control coupled analysis MTMD
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Towing characteristics of large-scale composite bucket foundation for offshore wind turbines 被引量:22
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作者 张浦阳 丁红岩 +1 位作者 乐丛欢 黄旭 《Journal of Southeast University(English Edition)》 EI CAS 2013年第3期300-304,共5页
In order to study the towing dynamic properties of the large-scale composite bucket foundation the hydrodynamic software MOSES is used to simulate the dynamic motion of the foundation towed to the construction site.Th... In order to study the towing dynamic properties of the large-scale composite bucket foundation the hydrodynamic software MOSES is used to simulate the dynamic motion of the foundation towed to the construction site.The MOSES model with the prototype size is established as the water draft of 5 and 6 m under the environmental conditions on site.The related factors such as towing force displacement towing accelerations in six degrees of freedom of the bucket foundation and air pressures inside the bucket are analyzed in detail.In addition the towing point and wave conditions are set as the critical factors to simulate the limit conditions of the stable dynamic characteristics.The results show that the large-scale composite bucket foundation with reasonable subdivisions inside the bucket has the satisfying floating stability.During the towing process the air pressures inside the bucket obviously change little and it is found that the towing point at the waterline is the most optimal choice.The characteristics of the foundation with the self-floating towing technique are competitive for saving lots of cost with few of the expensive types of equipment required during the towing transportation. 展开更多
关键词 large-scale composite bucket foundation TOWING MOSES offshore wind turbines
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Application of SABO-VMD-KELM in Fault Diagnosis of Wind Turbines
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作者 Yuling HE Hao CUI 《Mechanical Engineering Science》 2023年第2期23-29,共7页
In order to improve the accuracy of wind turbine fault diagnosis,a wind turbine fault diagnosis method based on Subtraction-Average-Based Optimizer(SABO)optimized Variational Mode Decomposition(VMD)and Kernel Extreme ... In order to improve the accuracy of wind turbine fault diagnosis,a wind turbine fault diagnosis method based on Subtraction-Average-Based Optimizer(SABO)optimized Variational Mode Decomposition(VMD)and Kernel Extreme Learning Machine(KELM)is proposed.Firstly,the SABO algorithm was used to optimize the VMD parameters and decompose the original signal to obtain the best modal components,and then the nine features were calculated to obtain the feature vectors.Secondly,the SABO algorithm was used to optimize the KELM parameters,and the training set and the test set were divided according to different proportions.The results were compared with the optimized model without SABO algorithm.The experimental results show that the fault diagnosis method of wind turbine based on SABO-VMD-KELM model can achieve fault diagnosis quickly and effectively,and has higher accuracy. 展开更多
关键词 Wind turbine generator Fault diagnosis Subtraction-Average-Based Optimizer(SABO) Variational Mode Decomposition(VMD) Kernel Extreme Learning Machine(KELM)
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Load Transferring Mechanism on Transition Section of Composite Bucket Foundation for Offshore Wind Turbines 被引量:2
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作者 Puyang Zhang Zhi Zhang +2 位作者 Junjie Ma Hongyan Ding Ruiqi Hu 《Transactions of Tianjin University》 EI CAS 2017年第5期434-444,共11页
The composite bucket foundation (CBF) is a new kind of foundation which has been applied in the offshore wind industry. A reasonable connection pattern between the tower and the CBF top cover is crucial for load trans... The composite bucket foundation (CBF) is a new kind of foundation which has been applied in the offshore wind industry. A reasonable connection pattern between the tower and the CBF top cover is crucial for load transmissions from the superstructure. Therefore, it is essential to choose an optimum structure type for the transition section. The line type and the arc transition section models were established by ABAQUS, and the internal forces of cross section were extracted along the height direction. Specifically, the force transfer mechanism for different types of the transition sections was investigated comparatively with monotonic as well as composite loadings. The results show that the curved transition structure exhibits the better mechanical characteristics under the monotonic and composite loadings, and the reason can be illustrated that its specific arc-shape structure can effectively convert the tremendous bending moment from the turbine tower into the limited tensile and compressive stresses downwards, without the occurrence of force concentration. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg. 展开更多
关键词 FOUNDATIONS Offshore wind turbines Steel beams and girders Wind turbines
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A computational platform for considering the effects of aerodynamic and seismic load combination for utility scale horizontal axis wind turbines 被引量:12
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作者 Mohammad-Amin Asareh Ian Prowell +1 位作者 Jeffery Volz William Schonberg 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第1期91-102,共12页
The wide deployment of wind turbines in locations with high seismic hazard has led engineers to take into account a more comprehensive seismic design of such structures. Turbine specific guidelines usually use simplif... The wide deployment of wind turbines in locations with high seismic hazard has led engineers to take into account a more comprehensive seismic design of such structures. Turbine specific guidelines usually use simplified methods and consider many assumptions to combine seismic demand with the other operational loads effecting the design of these structures. As the turbines increase in size and capacity, the interaction between seismic loads and aerodynamic loads becomes even more important. In response to the need for a computational tool that can perform coupled simulations of wind and seismic loads, a seismic module is developed for the FAST code and described in this research. This platform allows engineers working in this industry to directly consider interaction between seismic and other environmental loads for turbines. This paper details the practical application and theory of this platform and provides examples for the use of different capabilities. The platform is then used to show the suitable earthquake and operational load combination with the implicit consideration of aerodynamic damping by estimating appropriate load factors. 展开更多
关键词 renewable energy horizontal axis wind turbines aerodynamic-seismic load interaction aerodynamicdamping coupled simulations
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Intelligent control for large-scale variable speed variable pitch wind turbines 被引量:12
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作者 XinfangZHANG DapingXU YibingLIU 《控制理论与应用(英文版)》 EI 2004年第3期305-311,共7页
Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances. Automatic control is crucial for the efficiency and reliability of wind turb... Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances. Automatic control is crucial for the efficiency and reliability of wind turbines. On the basis of simplified and proper model of variable speed variable pitch wind turbines, the effective wind speed is estimated using extended Kaiman filter. Intelligent control schemes proposed in the paper include two loops which operate in synchronism with each other. At below-rated wind speed, the inner loop adopts adaptive fuzzy control based on variable universe for generator torque regulation to realize maximum wind energy capture. At above-rated wind speed, a controller based on least square support vector machine is proposed to adjust pitch angle and keep rated output power. The simulation shows the effectiveness of the intelligent control. 展开更多
关键词 Wind turbines Adaptive fuzzy control Least square support vector machine Variable speed Variable pitch
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Failure Envelopes of Wide-Shallow Composite Bucket Foundation for Offshore Wind Turbines in Silty Sand 被引量:6
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作者 Yonggang Liu Yaohua Guo +1 位作者 Hongyan Ding Puyang Zhang 《Transactions of Tianjin University》 EI CAS 2018年第2期182-190,共9页
The wide-shallow composite bucket foundation(WSCBF) is a new type of offshore wind power foundation that can be built on land and rapidly installed offshore, there by effectively reducing the construction time and cos... The wide-shallow composite bucket foundation(WSCBF) is a new type of offshore wind power foundation that can be built on land and rapidly installed offshore, there by effectively reducing the construction time and costs of offshore wind power foundation. In this study, the horizontal bearing capacity is calculated by finite element simulation and compared with test results to verify the validity of results. In this process, the vertical load and bending load are respectively calculated by the finite element simulation. Under the vertical load effect, the bucket foundation and the soil inside are regarded as a whole, and the corresponding buckling failure mode is obtained. The ultimate vertical bearing capacity is calculated using empirical and theoretical formulas; the theoretical formula is also revised by finite element results. Under bending load, the rotational center of the composite bucket foundation(in a region close to the bucket bottom) gradually moves from the left of the central axis(reverse to loading direction) to the nearby compartment boards along the loading direction. The H–M envelope line shows a linear relationship, and it is determined that the vertical and bending ultimate bearing capacities can be improved by an appropriate vertical load. 展开更多
关键词 Wide-shallow COMPOSITE BUCKET FOUNDATION Silty sand Off SHORE wind turbines
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Review of Experimental-Numerical Methodologies and Challenges for Floating Offshore Wind Turbines 被引量:5
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作者 Peng Chen Jiahao Chen Zhiqiang Hu 《Journal of Marine Science and Application》 CSCD 2020年第3期339-361,共23页
Due to the dissimilar scaling issues,the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately.Therefore,it is of absolute necessity to fi... Due to the dissimilar scaling issues,the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately.Therefore,it is of absolute necessity to find a more accurate,economic and efficient approach,which can be utilized to predict the full-scale global dynamic responses of FOWTs.In this paper,a literature review of experimental-numerical methodologies and challenges for FOWTs is made.Several key challenges in the conventional basin experiment issues are discussed,including scaling issues;coupling effects between aero-hydro and structural dynamic responses;blade pitch control strategies;experimental facilities and calibration methods.Several basin experiments,industrial projects and numerical codes are summarized to demonstrate the progress of hybrid experimental methods.Besides,time delay in hardware-in-the-loop challenges is concluded to emphasize their significant role in real-time hybrid approaches.It is of great use to comprehend these methodologies and challenges,which can help some future researchers to make a footstone for proposing a more efficient and functional hybrid basin experimental and numerical method. 展开更多
关键词 Floating offshore wind turbines Hybrid approach Basin experiment Numerical simulation Wind energy
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Experimental Investigation of Local Scour Around A New Pile-Group Foundation for Offshore Wind Turbines in Bi-Directional Current 被引量:4
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作者 JI Chao ZHANG Jin-feng +2 位作者 ZHANG Qing-he LI Ming-xing CHEN Tong-qing 《China Ocean Engineering》 SCIE EI CSCD 2018年第6期737-745,共9页
The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity ... The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity and topography of the seabed were measured based on a system composed of plane positioning equipment and an ADV.Experimental results indicate that the development of the scour hole was fast at the beginning, but then the scour rate decreased until reaching equilibrium. Erosion would occur around each pile of the foundation. In most cases, the scour pits were connected in pairs and the outside widths of the scour holes were larger than the inner widths. The maximum scour depth occurred at the side pile of the foundation for each test. In addition, a preliminary investigation shows that the larger the flow velocity, the larger the scour hole dimensions but the shorter equilibrium time. The field maximum scour depth around the foundation was obtained based on the physical experiments with the geometric length scales of 1:27.0, 1:42.5 and 1:68.0, and it agrees with the scour depth estimated by the HEC-18 equation. 展开更多
关键词 offshore wind turbines new pile-group foundation local scour bi-directional current
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Decoupling Adaptive Sliding Mode Observer Design for Wind Turbines Subject to Simultaneous Faults in Sensors and Actuators 被引量:3
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作者 Hamed Habibi Ian Howard +1 位作者 Silvio Simani Afef Fekih 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2021年第4期837-847,共11页
This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator... This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator and sensor faults without the need for any redundant hardware components.Additionally,wind speed variations are considered as unknown disturbances,thus eliminating the need for accurate measurement or estimation.The proposed ASMO enables the accurate estimation and reconstruction of the descriptor states and disturbances.The proposed design implements the principle of separation to enable the use of the nominal controller during faulty conditions.Fault tolerance is achieved by implementing a signal correction scheme to recover the nominal behavior.The performance of the proposed approach is validated using a 4.8 MW wind turbine benchmark model subject to various faults.Monte-Carlo analysis is also carried out to further evaluate the reliability and robustness of the proposed approach in the presence of measurement errors.Simplicity,ease of implementation and the decoupling property are among the positive features of the proposed approach. 展开更多
关键词 Fault tolerant control horizontal axis wind turbines Monte-Carlo analysis principle of separation simultaneous faults sliding mode observer
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