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1.
To simplify signal analysis on wind turbine blades and enable their efficient monitoring, this paper presents a novel method of transforming blade moment signals on a horizontal axis 3-blade wind turbine. Instead of processing 3-blade moment signals directly, the proposed algorithm transforms the three sinusoidal signals into two static signals relative to the center of blade rotation through vector synthesis and coordinate transformation, and eliminates frequency components due to blade rotation from the obtained signals. Moreover, as an alternative to a rotational sensor, a blade rotation angle estimator is introduced. Its effectiveness was confirmed through simulations and field tests on an actual wind turbine.  相似文献   

2.
应用现代柔性多体动力学和有限元数值分析相结合的理论建立风力机旋转叶片结构的系统动力学方程,并对微分方程数值求解的方法进行了研究;运用Bladed软件对1.5 MW风力发电机进行建模,分析叶片的结构动力学响应,得到系统的固有频率以及正常工况、启动工况和停车工况下3叶片挥舞方向和摆振方向的振动位移情况,判断风力发电机组运行的稳定性。  相似文献   

3.
This paper investigates an advanced vertical axis turbine to enhance power generation from water energy. The turbine, known as a cycloidal water turbine, is a straight-bladed type adopting a cycloidal blade system that actively controls the rotor blades for improved turbine efficiency, according to the operating conditions. These characteristics enable the turbine to self-start and produce high electric power at a low flow speed, or under complex flow conditions. A parametric study has been carried out by CFD analysis, with various characteristics including different number of blades, chord length variations, variety of tip speed ratios, various hydrofoil shapes, and changing pitch and phase angles. Optimal parameters have been determined, and the performance of the turbine has achieved approximately 70% better performance than that of a fixed pitch turbine. An experimental study has also been carried out which shows that the results correlate quite well with the theoretical predictions although the power output was reduced due to the drag forces of the mechanical devices. Another numerical optimization was carried out to improve the rotor performance by adopting an individual blade control method. Controllable pitch angles were employed to maximize the rotor performance at various operating conditions. The optimized result obtained using genetic algorithm and parallel computing, shows an improvement in performance of around 25% compared with the cycloidal motion.  相似文献   

4.
The scope of this article is to investigate the aeroelastic stability of wind turbine blade sections subjected to combined flap/lead–lag motion. The work is motivated by recent concern about destructive ‘edgewise' vibrations of modern, half‐megawatt‐scale, blades. The aeroelastic governing equations derive from the combination of a spring–mass–damper equivalent of the structure and a ‘non‐stationary' aerodynamic model. The aerodynamic model used in the present context is the differential dynamic stall model developed at ONERA. The resulting equations of motion are linearized and their stability characteristics are investigated in terms of the system entries, expressed through suitable, non‐dimensional, structural and aerodynamic parameters. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

5.
经过数百万年的进化,鸮形目鸟类在其飞行行为上显现出许多优异的特征。文章选取鸮翼的非光滑前缘作为仿生对象,设计出一种仿生风力机叶片,并分析非光滑前缘结构对风力机叶片气动性能的影响。采用S-A湍流模型,对低雷诺数下原型风力机叶片和仿生风力机叶片进行绕流流场模拟。模拟结果表明,在大攻角下,仿生风力机叶片的前缘凸起能够改变气流在叶片表面的流向分布,使气流在吸力面仍保持附着流动,进而减少叶片吸力面的失速区,有效延缓叶片失速现象的发生,从而使得仿生风力机叶片的失速角比原型风力机叶片的失速角推迟了10°左右,改善了风力机叶片的气动性能。  相似文献   

6.
In this paper, we consider the problem of reducing the radar cross section of a wind turbine blade through the application of radar absorbing material (RAM). One problem encountered by these techniques is the integration of the RAM solution with the existing lightning protection system, which is mandatory requirement to protect the blade when in operation. A common form of lightning protection is the use of conducting lightning receptors on the surface of the blade. To ensure the protection system is effective, a clearance area around the receptor may be required before any RAM treatment is applied. The size of the clearance area and the number of lightning receptors therefore potentially reduce the effectiveness of the RAM treatment. Design guidelines are given in this paper for a generic 40 m blade geometry. Some modelling results of the radar cross section and Doppler signature from a RAM treated blade are presented, and a comment is also made on the importance the blade edges have in reducing radar effects. ©2013 The Authors. Wind Energy published by John Wiley & Sons, Ltd.  相似文献   

7.
8.
This paper describes the numerical simulation of three-dimensional viscous flows in fir-cooled turbine blade rows with the effects of coolant ejection. A TVD Navier-Stokes flow solver incorporated with Baldwin-Lomax turbulence model and multi-grid convergence acceleration algorithm are used for the simulation. The influences of coolant ejection on the main flow are accounted by volumetric coolant source terms. Numerical results for a four-stage turbine are presented and discussed.  相似文献   

9.
A numerical tool for investigating the aeroelastic stability of a single wind turbine blade subjected to combined flap/lead–lag motion is presented. Its development is motivated by recent concern about destructive edgewise vibrations of modern stall‐controlled blades. The stability tool employs a finite element formulation to discretize in space the structural and aerodynamic governing equations. Unsteady aerodynamics is considered by means of the extended ONERA lift and drag models. The mathematical form of these models allows for a combined treatment of dynamics and aerodynamics through the introduction of a so‐called ‘aeroelastic beam element’. This is an extended two‐node beam element having both deformation and aerodynamic degrees of freedom. Several linear and non‐linear versions of the stability tool are available, differing in the way that instantaneous lift and/or drag is treated. In the linear case, stability is investigated through eigenvalue analysis. Time domain integration is employed for non‐linear stability analysis. Results are presented and discussed for a 17 m stall‐controlled blade. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

10.
Composite components of wind turbine blade are assembled with adhesive. In order to assess structural integrity of blades it is needed to investigate fracture of joints. In this study, finite element analysis based on fracture mechanics was conducted to characterize failure of adhesive joint for wind turbine blade. The cohesive zone model as proposed fracture mechanics approach was verified through the comparison of numerical results with experimental data. Finite element models of wind turbine were developed to predict damage initiation and propagation. Numerical results based on fracture mechanics showed that failure was initiated in the edge of the adhesive bond line due to high level of shear stress prior to reaching the extreme design loading and propagated progressively.  相似文献   

11.
12.
利用有限元分析软件对风力机叶片在不同平均风速作用下的挠度和应力进行了分析。采用Davenport脉动风速谱模拟出不同平均风速,并计算出叶片各部位的挠度及其应力分布。计算结果表明,叶片的振动主要以挥舞振动为主,随着工作风速的增大,叶片挥舞振幅增大,叶片承受的mises应力主要集中在叶片迎风面的中部位置。该研究为风力机叶片的安全设计提供了技术参考。  相似文献   

13.
Mitigating loads on a wind turbine rotor can reduce the cost of energy. Sweeping blades produces a structural coupling between flapwise bending and torsion, which can be used for load alleviation purposes. A multidisciplinary design optimization (MDO) problem is formulated including the blade sweep as a design variable. A multifidelity approach is used to confront the crucial effects of structural coupling on the estimation of the loads. During the MDO, ultimate and damage equivalent loads are estimated using steady‐state and frequency‐domain–based models, respectively. The final designs are verified against time‐domain full design load basis aeroelastic simulations to ensure that they comply with the constraints. A 10‐MW wind turbine blade is optimized by minimizing a cost function that includes mass and blade root flapwise fatigue loading. The design space is subjected to constraints that represent all the necessary requirements for standard design of wind turbines. Simultaneous aerodynamic and structural optimization is performed with and without sweep as a design variable. When sweep is included in the MDO process, further minimization of the cost function can be obtained. To show this achievement, a set of optimized straight blade designs is compared to a set of optimized swept blade designs. Relative to the respective optimized straight designs, the blade mass of the swept blades is reduced of an extra 2% to 3% and the blade root flapwise fatigue damage equivalent load by a further 8%.  相似文献   

14.
Hui Chen  Wenbin Yu  Mark Capellaro 《风能》2010,13(6):497-516
The purpose of this paper is to critically assess several computer tools for calculating the inertial and structural properties of wind turbine blades. The theoretical foundation of each tool is briefly summarized, and the advantages and disadvantages of each tool are pointed out. Several benchmark examples, including a circular aluminium tube, a highly heterogeneous section, a multi‐layer composite pipe, an isotropic blade‐like section and a realistic composite wind turbine blade are used to evaluate the performance of different tools. Such a systematic and critical assessment provides guidance for wind turbine blade engineers to choose the right tool for effective design and analysis of wind turbine blades. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

15.
Large wind turbine blades are being developed at lengths of 75–100 m, in order to improve energy capture and reduce the cost of wind energy. Bending loads in the inboard region of the blade make large blade development challenging. The “biplane blade” design was proposed to use a biplane inboard region to improve the design of the inboard region and improve overall performance of large blades. This paper focuses on the design of the internal “biplane spar” structure for 100-m biplane blades. Several spars were designed to approximate the Sandia SNL100-00 blade (“monoplane spar”) and the biplane blade (“biplane spar”). Analytical and computational models are developed to analyze these spars. The analytical model used the method of minimum total potential energy; the computational model used beam finite elements with cross-sectional analysis. Simple load cases were applied to each spar and their deflections, bending moments, axial forces, and stresses were compared. Similar performance trends are identified with both the analytical and computational models. An approximate buckling analysis shows that compressive loads in the inboard biplane region do not exceed buckling loads. A parametric analysis shows biplane spar configurations have 25–35% smaller tip deflections and 75% smaller maximum root bending moments than monoplane spars of the same length and mass per unit span. Root bending moments in the biplane spar are largely relieved by axial forces in the biplane region, which are not significant in the monoplane spar. The benefits for the inboard region could lead to weight reductions in wind turbine blades. Innovations that create lighter blades can make large blades a reality, suggesting that the biplane blade may be an attractive design for large (100-m) blades.  相似文献   

16.
Mini turbo-pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices, washing machine pump and so on. Further, the needs for mini turbo-pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini turbo-pump design is as simple as possible due to restriction to make precise manufactures. But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps. Three types of rotors with different outlet angles are prepared for an experiment and a numerical analysis. The performance tests are conducted with these rotors in order to investigate the effect of the blade outlet angle on performance and internal flow condition of mini turbo-pumps. It is clarified from the experimental results that head of the mini turbo-pump increases and maximum efficiency flow rate shifts to larger flow rate according to the increase of the blade outlet angle, however the maximum efficiency decreases with the increase of it. In the present paper, the performance of the mini turbo-pump is shown and the internal flow conditions are clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle on the performance are investigated and high performance design with simple structure for the mini turbo-pump would be considered.  相似文献   

17.
A computational model of rain erosion of wind turbine blades is presented. The model is based on the transient fluid–solid coupled finite element (FE) analysis of rain droplet/coating interaction and fatigue degradation analysis. The fatigue analysis of the surface degradation is based on multiaxial fatigue model and critical plane theory. The random rain fields are constructed computationally, and the estimated droplet sizes are included in FE model to acquire a library of load histories. Subsequently, the resulted nonproportional multiaxial high cycle fatigue problem is solved to assess the damage and lifetimes of the coatings. The approach can be used to design new coating systems withstanding longer service times.  相似文献   

18.
Horizontal axis wind turbines operate under yawed conditions for a considerable period of time due to the power control mechanism or sudden changes in the wind direction. This in turn can alter the dynamic characteristics of a turbine blade because the flow over the rotor plane may trigger complicated induced velocity patterns. In this study, an aeroelastic analysis under yawed flow conditions is carried out to investigate the effects of yaw error on the blade behaviors and dynamic stability. A beam model including geometric nonlinearity coupled with unsteady aerodynamics based on a free-vortex wake method with the blade element theory is employed in the present study. The aerodynamic approach for a horizontal axis wind turbine blade under yawed flow conditions is verified through comparison with measurements. It is also shown that the present method gives slightly better results at high yaw angles than does the method previously published in the literature. The dynamic instabilities of a National Renewable Energy Laboratory 5 MW reference wind turbine have subsequently been investigated for various wind speeds and yaw angles. Observations are made that yaw effects induce considerable changes in airloads and blade structural behavior. Also, the aeroelastic damping values for this particular blade under yawed flow conditions can be reduced by up to approximately 33% in the worst case. Therefore, it is concluded that the impacts of yaw misalignments adversely influenced the dynamic aeroelastic stability of the horizontal axis wind turbine blade.  相似文献   

19.
This short communication reports on a radar approach for structural health monitoring of wind turbine blades. Therefore, a bistatic frequency‐modulated continuous wave (FMCW) radar in the frequency range from 33.4 to 36.0 GHz has been developed and tested experimentally using a laboratory wind turbine demonstrator. A differential damage localization framework is presented here that exploits signal differences between measurements from the intact and the damaged structure for 3D imaging of the defect. We have achieved the localization of a 30‐mm cut in a glass fiber composite structure as well as the localization of a water pack at the backside of the specimen with a localization error of several centimeters.  相似文献   

20.
采用边界元并结合多体动力学方法分析了张力腿平台(TLP)漂浮式风力机结构,研究了平台结构在不同方向上的频域与时域运动响应变化,并比较了漂浮式平台在海洋环境条件下风波流联合作用时和波浪载荷独立作用时的运动响应,得到了平台结构在时域中的动力响应.研究结果表明:漂浮式平台在频域变化范围内,运动响应主要集中在低频部分,绕射力对漂浮式海上风力机TLP的作用力不能忽略;风波流联合作用时的运动响应标准差大于波浪载荷独立作用时的运动响应标准差,且平台偏离平衡位置的程度更加剧烈;平均运动响应及标准差在入射角分别为0°、22.5°和45°时相差微小.研究结果对海上张力腿平台结构设计与优化具有很高的参考价值.  相似文献   

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