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风力机叶片三维流动特性与气动性能的数值分析 总被引：5，自引：0，他引：5
采用基于雷诺平均的三维可压N-S方程,对美国国家可再生能源实验室开发的PhaseⅥ实验风力机叶片在7m/s来流下的绕流流场进行全三维数值模拟.通过对数值模拟得到的叶片表面压力分布与实验测量值的比较,验证了数值模拟的有效性,并在此基础上分析了叶片各截面的失速情况、叶片的三维绕流特性以及叶展方向上的升阻力系数与功率分布.数值模拟数据显示,相比简单的对二维数值模拟结果进行堆叠,全三维的数值模拟能够更准确的反映叶片绕流的气动特性. 相似文献
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This paper investigates wake effects on load and power production by using the dynamic wake meander (DWM) model implemented in the aeroelastic code HAWC2. The instationary wind farm flow characteristics are modeled by treating the wind turbine wakes as passive tracers transported downstream using a meandering process driven by the low frequent cross‐wind turbulence components. The model complex is validated by comparing simulated and measured loads for the Dutch Egmond aan Zee wind farm consisting of 36 Vestas V90 turbine located outside the coast of the Netherlands. Loads and production are compared for two distinct wind directions—a free wind situation from the dominating southwest and a full wake situation from northwest, where the observed turbine is operating in wake from five turbines in a row with 7D spacing. The measurements have a very high quality, allowing for detailed comparison of both fatigue and min–mean–max loads for blade root flap, tower yaw and tower bottom bending moments, respectively. Since the observed turbine is located deep inside a row of turbines, a new method on how to handle multiple wakes interaction is proposed. The agreement between measurements and simulations is excellent regarding power production in both free and wake sector, and a very good agreement is seen for the load comparisons too. This enables the conclusion that wake meandering, caused by large scale ambient turbulence, is indeed an important contribution to wake loading in wind farms. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Non‐torque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling and experimental approaches to evaluate two distinct drivetrain designs that minimize the effects of non‐torque loads on gearbox reliability: a modified three‐point suspension drivetrain studied by the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) and the Pure Torque® drivetrain developed by Alstom. In the original GRC drivetrain, the unequal planetary load distribution and sharing were present and they can lead to gear tooth pitting and reduce the lives of the planet bearings. The NREL GRC team modified the original design of its drivetrain by changing the rolling element bearings in the planetary gear stage. In this modified design, gearbox bearings in the planetary gear stage are anticipated to transmit non‐torque loads directly to the gearbox housing rather than the gears. Alstom's Pure Torque drivetrain has a hub support configuration that transmits non‐torque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom's Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces and the resulting drivetrain loads. In Alstom's Pure Torque drivetrain, main shaft bending loads are orders of magnitude lower than the rated torque and hardly affected by wind speed, gusts or turbine operations. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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以IEA Wind 15 MW 参考风电机组为研究对象,基于非线性时域气弹耦合分析工具,研究风剪切、偏航入流、质量不平衡3种不平衡载荷单一或共同作用时,超大型风电机组叶片的颤振极限。结果表明,单一不平衡载荷作用时,风剪切和±15°以内的偏航角会增大临界颤振速度,而质量不平衡会降低临界颤振速度,且质量偏重时颤振速度下降更加明显。3种不平衡载荷共同作用时,临界颤振速度的最大值和最小值都出现在剪切系数为0.3时;最大值总是在偏航角为非负值时取得,最小值在偏航角为- 20 ° - 20 °
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采用CFD方法,以NH1500三叶片大型水平轴风力机为研究对象,研究额定风速剪切来流下的塔影效应对水平轴风力机叶片和风轮非定常气动载荷的影响。结果表明：剪切来流下,叶片和风轮的气动载荷均呈余弦变化规律,塔影效应的主要影响叶片方位角范围为160°~210°,且该范围不随风剪切指数的变化而变化。相同风剪切指数下,塔影效应对叶片和风轮气动载荷的均方根影响较小,对其波动影响较大。当风剪切指数从0.12增至0.30时,塔影效应下,叶片气动载荷的均方根减小,推力和转矩的波动幅度增大,偏航力矩和倾覆力矩的波动幅度减小;风轮推力和转矩的均方根减小,波动幅度变化较小,而倾覆力矩和偏航力矩的均方根增大,且波动幅度也增大。 相似文献
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Micro‐generation is being widely promoted as a way for householders in the UK and elsewhere to take part in ‘the Green Revolution’. Building‐integrated wind turbines (BIWTs) provide a way to do this, enabling people to reduce their contribution to the problems of both climate change and decreasing fossil fuel availability. Although energy yields from BIWTs for many householders have been shown to be low, there are still situations where such turbines can make a useful contribution to electricity generation, e.g. in windier areas and for isolated detached buildings. The standards for the installation of BIWTs are still being developed including those for the safe mounting of turbines on domestic buildings. This paper investigates the current trend for mounting small wind turbines on the walls of domestic premises and compares this with an approach which uses roof timbers. It identifies the main characteristics of building construction which affect the integrity of such installations. European and British standards have been used to calculate wind and gravitational loads. Finite element models are used to derive working stresses and, hence, some basic principles of good design. The likely costs of wall and roof mounting are then compared. Installation and health and safety issues are also examined briefly. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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风力机专用翼型发展现状及其关键气动问题分析 总被引：4，自引：0，他引：4
介绍了风力机翼型的设计要求和主要方法,提出了预测翼型气动性能的合理途径,探讨了二维翼型气动数据的三维旋转修正问题。 相似文献
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为探究翼型表面污染对其气动性能的影响,基于SST k-ω 1 %c 、 5 %c 1 %c 、 9 %c
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旋转叶片振动参数的非接触测量 总被引：1，自引：0，他引：1
描述了问题的工程背景,整级旋转叶片振幅、频率的测量系统、测量原理和数学模型。给出了在实验室和在燃气轮机机组、电厂在线监测的实例。 相似文献
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Unsteady power output and long‐term loads (extreme and fatigue) drive wind turbine design. However, these loads are difficult to include in optimization loops and are typically only assessed in a post‐optimization load analysis or via reduced‐order methods. Both alternatives yield suboptimal results. The reason for this difficulty lays in the deterministic approaches to long‐term loads assessment. To model the statistics of lifetime loads they require the analysis of many unsteady load cases, generated from many different random seeds—a computationally expensive procedure. In this paper, we present an alternative: a stochastic solution for the unsteady aerodynamic loads based on a projection of the unsteady Blade Element Momentum (BEM) equations onto a stochastic space spanned by chaos exponentials. This approach is similar to the increasingly popular polynomial chaos expansion, but with 2 major differences. First, the BEM equations constitute a random process, varying in time, while previous polynomial chaos expansion methods were concerned with random parameters (ie, random but constant in time or initial values). Second, a new, more efficient basis (the exponential chaos) is used. This new stochastic method enables us to obtain unsteady long‐term loads much faster, enabling unsteady loads to become accessible inside wind turbine optimization loops. In this paper we derive the stochastic BEM solution and present the most relevant results showing the accuracy of the new method. 相似文献
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分别采用均匀风和剪切风对1.3 MW失速调节风力机整机在8 m/s和13 m/s来流风速下的绕流流场进行全三维定常数值模拟。根据模拟结果分析叶片不同截面的压力系数分布、沿叶展方向的功率分布、风轮三维流场细节、风轮下游不同距离处的静压分布和二维相对速度矢量分布情况。结果表明：剪切风下,风力机功率计算值与设计值吻合较好;在靠近叶根处,适当地减小有效攻角可提高翼型气动性能,选择适应较大攻角的翼型,可以提高叶根处的输出功率;在靠近叶尖的部位,适当增加有效攻角,同时选择适应小攻角的翼型可以提高叶尖处的输出功率;在叶根部位,发生了明显的流动分离;塔架与轮毂所在位置的下游尾迹处产生的漩涡和干扰要远远大于叶轮面其他部位。 相似文献
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本文运用计算流体力学方法,以1.5 MW风力机为例,对风力机整机三维模型的空气动力学特性开展研究。针对三翼型风力机叶片,利用改进的Wilson方法进行气动设计,并通过寻找各截面最佳雷诺数的方法进行优化修正。建立了整机三维模型,设计流域并划分网格,定义边界及区域。最后对上述模型进行额定工况下定常与非定常数值模拟,利用模拟结果开展有关压力、失速特性等空气动力学特性的分析。结果表明：非定常模拟在风轮背面上的平均压力比定常小,使风轮前后压差变大,输出功率加大,其主要原因是叶尖出力的增加;旋转使得风力机叶片发生流体分离延迟,且产生更高的升力系数。 相似文献
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Wind turbine blades often present complex distributions of their stiffness, mass and inertial properties along the span. We propose a method to estimate such physical parameters so as to match given experimental observations. The procedure can be used to understand the nature of possible discrepancies between designed and manufactured blades and to provide updated high fidelity mathematical beam models to be used in aero‐elastic simulations. The formulation is based on the constrained optimization of a maximum likelihood cost function and a noisy measurement fusion approach whereby the data of multiple experiments are used simultaneously in a single estimation process. The proposed method is demonstrated first using simulated data and then in the identification of two real small wind turbine blades. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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为在研究大型风力机气动性能的同时考虑其结构动力学特性,基于开源计算流体力学软件OpenFOAM及气动-水动-伺服-控制软件FAST,并结合致动线方法(Actuator Line Method,ALM)实现风力机叶轮周围流场信息与结构响应间的数据交换,最终完成风力机气动-结构仿真平台FASTFOAM构建。通过该平台计算了风场中两台串列布置5 MW风力机的气动性能及结构动力学特性。结果表明:FASTFOAM平台能够快速计算出风力机的功率输出、结构响应及流场信息;风力机尾迹在发展过程中可持续与周围流场进行能量交换而使其速度亏损得以弥补;下游风力机受上游风力机尾迹影响严重,输出功率只有上游风力机的21.05%,且结构动力学响应与上游风力机不同;上游风力机和下游风力机叶轮的主要刺激频率分别为0.16和0.15 Hz。 相似文献
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Florian Sayer Falko Bürkner Benjamin Buchholz Michael Strobel Arno M. van Wingerde Hans‐Gerd Busmann Henry Seifert 《风能》2013,16(2):163-174
This paper presents results out of investigations of the DEBRA‐25 wind turbine blades. Almost unique in the history of modern wind energy, these blades were in operation for 18 years next to a weather station and were investigated afterward. Therefore, the loads experienced in the operational life could be post‐processed accurately with the measured data of the weather station and the turbine. The blades are made of materials that are similar with today's wind turbines. Furthermore, intensive laboratory tests and free field tests have been carried out, and all load assumptions and data and results are still available today. The results include experimental investigations on the moisture content of the load‐carrying material, static and fatigue behavior of the material, the relaxation of the coupling joints, the natural frequencies of the blade and a full scale static blade test. It is shown that the structural performance of the DEBRA‐25 service blades is comparable with modern wind turbine blades. Although some damage was found by visual inspection, the service blade of the DEBRA‐25 showed excellent mechanical behavior in the full scale blade test. Only small changes of the edgewise eigenfrequencies were detected. The pre‐tensioning forces of the IKEA bolts, where the two blade parts are connected, were measured and were still adequate. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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A method is presented for extracting the equivalent beam properties from a finite element model of a wind turbine blade so that full aeroelastic models can be constructed more reliably. The method is based on applying unit loads at the tip of the blade and processing the resulting nodal displacements to generate the 6 × 6 stiffness matrices for the specified beam discretization. The finite element model can comprise shell and/or solid elements, but the use of shell elements with centroids offset from the surface has been shown to produce erroneous torsional stiffness values. The method includes all three‐dimensional effects such as shear and warping as well as flap–twist coupling, and these are demonstrated in a series of validation examples. The process will accommodate blades with curvature in one or both directions and has the added advantage of identifying the centre of mass, elastic centre, principal directions and shear centre. Published in 2006 by John Wiley &Sons, Ltd. 相似文献
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偏侧风对风力机气动性能的影响 总被引：2，自引：0，他引：2
针对偏侧风对风力机气动性能影响的研究问题,用相对运动法作偏侧风的矢量分解,获得各风速分量的时间空间变化性质;在气动性能的计算模型中分离出偏侧风扰动项,分析了偏侧风对气动力的影响机理;用差值比较法在实例计算中得到偏侧风的气动推力和力矩,得出偏侧风对风力机具有周期性局部冲击的结论,为综合研究风力机风速风向变化下的气动特性及风电传动系统动力学行为提供了支持。 相似文献
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增加风力机叶片翼型后缘厚度对气动性能的影响 总被引：5，自引：1，他引：5
以FFA-W3翼型族为研究对象,对其系列翼型的后缘作了加厚处理。利用XFOIL软件对修改前后的翼型的气动性能进行了计算,利用Viterna-Corrigan失速后模型将气动性能数据的攻角扩展到了90°。对修改前后的翼型的气动性能数据的改变作了对比分析。利用原翼型和修改后翼型的气动性能数据对同一个风力机进行了气动性能计算,并对计算结果作了对比分析。结论认为,对翼型后缘进行适当加厚处理对气动性能影响不大,为满足工艺要求在叶片的生产中对翼型后缘作加厚处理是可行的。 相似文献
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P. MalhotraR.W. Hyers J.F. ManwellJ.G. McGowan 《Renewable & Sustainable Energy Reviews》2012,16(1):284-292
Since the blades are one of the most critical components of a wind turbine, representative samples must be experimentally tested in order to ensure that the actual performance of the blades is consistent with their specifications. In particular, it must be demonstrated that the blade can withstand both the ultimate loads and the fatigue loads to which the blade is expected to be subjected during its design service life. In general, there are basically two types of blade testing: static testing and fatigue (or dynamic) testing. This paper includes a summary review of different utility-scale wind turbine blade testing methods and the initial design study of a novel concept for tri-axial testing of large wind turbine blades. This new design is based on a blade testing method that excites the blade in flap-wise and edgewise direction simultaneously. The flap motion of the blade is caused by a dual-axis blade resonance excitation system (BREX). Edgewise motion is delivered by the use of two inclined hydraulic actuators and linear guide rail system is used to move the inclined actuators in the flap-wise direction along the blade motion. The hydraulic system and linear guide rail requirements are analyzed and an initial cost estimate of the proposed system is presented. Recommendations for future work on this proposed system are given in the final section of this work. 相似文献