大型风力机叶片的耦合优化方法

为了降低兆瓦级风力机叶片的制造成本,通过耦合叶素动量理论与复合材料欧拉伯努利梁强度设计理论,综合考虑风能效率和成本,以叶片的风能效率成本最小化为优化目标,提出了大型风力发电机叶片的多学科优化设计方法。并基于该方法,对某50 m风力机叶片进行了优化设计。研究结果表明,该方法能够找到风能效率与成本的平衡设计点,叶片风能效率成本比传统设计方法设计的叶片减少了8.84%。     

Integrated aero-structural optimization design of pre-bend wind turbine blades

In the optimization design of a pre-bend wind turbine blade, there is a coupling relationship between blade aerodynamic shape and structural layup. The evaluation index of a wind turbine blade not only shows on conventional ones, such as Annual energy production (AEP), cost, and quality, but also includes the size of the loads on the hub or tower. Hence, the design of pre-bend wind turbine blades is a true multi-objective engineering task. To make the integrative optimization design of the pre-bend blade, new methods for the blade’s pre-bend profile design and structural analysis for the blade sections were presented, under dangerous working conditions, and considering the fundamental control characteristics of the wind turbine, an integrated aerodynamic-structural design technique for pre-bend blades was developed based on the Multi-objective particle swarm optimization algorithm (MOPSO). By using the optimization method, a three-dimensional Pareto-optimal set, which can satisfy different matching requirements from overall design of a wind turbine, was obtained. The most suitable solution was chosen from the Pareto-optimal set and compared with the original 1.5 MW blade. The results show that the optimized blade have better performance in every aspect, which verifies the feasibility of this new method for the design of pre-bend wind turbine blades.

     

风电叶片疲劳加载系统的运动分析及优化

采用两轴加载(翼面向共振)方式实现兆瓦级风电叶片疲劳寿命检测,并就关键部件——翼面向加载装置和翼弦向加载装置之间的运动耦合问题进行分析.对翼弦向加载机构的设计与分析,采用协调曲线法,利用MATLAB优化工具箱实现机构多目标函数的优化,得到翼弦向加载机构优化的偏心距、杆长及位移曲线,并得到同频和异频条件下叶片的运动轨迹.为后续的动力学分析、液压系统及控制系统设计等提供必要的理论分析基础,同时,也为该技术的实际工程应用提供理论依据.     

兆瓦级风力发电机组叶片设计

研究了兆瓦级风力发电机叶片翼型建模的方法,应用UG、Matlab建立叶片实体模型,提高了建模效率,为后续结构强度、叶片的力学特性计算等进一步分析奠定了基础。     

基于IABC算法的风力机叶片参数优化

为了降低风力机叶片的单位输出能量成本,改善风能利用情况,将风力机叶片的弦长、扭角和相对厚度参数作为设计变量,建立了叶片单位输出能量成本最小的目标函数,运用改进人工蜂群算法(IABC算法)对风力机叶片不同截面进行参数优化,并对叶片单位输出能量成本进行分析和验证。研究表明,某2MW的风力机叶片经优化后,年输出能量增加了0.5%,叶片成本减少了1.9%,叶片单位输出能量成本降低了2.4%。     

Aerodynamic shape optimization of wind turbine rotor blades considering aeroelastic deformation effect

An aerodynamic shape optimization framework of two modules is developed for improving the aerodynamic performance of wind turbine rotor blades. The first module conducts CFD-based aeroelastic analysis for the complete blade configuration to evaluate the turbine performance and to extract the sectional flow conditions at selected blade sections. The second module performs 2-D shape optimization of blade sections to maximize the lift-to-drag ratio under given sectional flow conditions. When the optimization is completed for all selected blade sections, the performance and sectional flow characteristics of the new blade reconfigured from the optimized sections are evaluated again by the CFD-based aeroelastic analysis. The above procedure is repeated until the solution converges satisfactorily. Applications were made for the NREL phase VI and the NREL 5MW reference wind turbines. The results showed that the optimization framework can be effectively utilized in enhancing the aerodynamic performance of wind turbine blades.

     

风力发电机叶片损伤演化预测方法研究

根据风力发电机叶片的实际铺层和使用状况,以刚度退化模型为基础,发展了一个适合于风力发电机叶片的损伤演化模型,模型的基本思路是以单层板的刚度退化规律来预测整个叶片的损伤演化过程.对损伤过程进行了分析,给出了复合材料层合板刚度退化、内部损伤和损伤累积规律.     

Value range optimization of ply parameter for composite wind turbine blades based on sensitivity analysis

Journal of Mechanical Science and Technology - Blade ply parameters are important design factors that influence the performances of wind turbine blades. This paper proposes a sensitivity analysis...     

风力机桨叶翼型的气动特性分析

为了探讨风力机翼型的气动特性，利用计算流体力学软件对风力机中常用的NACA63—215翼型进行了数值分析，得出了NACA63-215翼型的升力系数、阻力系数及升阻比随来流攻角的变化关系；并根据数值计算的结果分析了NACA63—215翼型的气动特性。     

Separation blockage-correction method for the airfoil of a wind turbine blade

A new blockage-correction method for the separated flows around the airfoil of a wind turbine blade was developed for the wall interference correction of the closed test-section wind tunnel. A wind tunnel test was performed for the airfoil at an angle-of-attack range of 0–180°. The freestream velocity was 15 m/s, which corresponds to a Reynolds number of 2.3 × 10⁵ based on the chord. Then a blockage correction for the separated flows was obtained with respect to the multiplication of the blocking area and the separation drag coefficient based on the test. The present method was validated by comparing the corrected results with those of the existing classical and measured-boundary-condition methods. The results of the classical method are similar to those of the measured-boundary-condition method at the attached flow region; however, at high angles of attack, the difference in the corrected results between the classical and MBC methods becomes significantly large. The present method is in good agreement with the measured-boundary-condition method, enabling better wall corrections than the classical method in post-stall region.     

基于逆向工程的风力机叶片动态特性分析

综合逆向工程软件imageware,三维造型软件UG和有限元软件ANSYS,建立了750kw风力机旋转风轮的实体模型和有限元模型,对其振动模态做了仿真分析,得到振动模态数值分析结果,对叶片的动态特性进行了分析和比对,为叶片的进一步研究提供了可靠的基础。     

Aeroacoustic simulations of a blunt trailing-edge wind turbine airfoil

We demonstrate the effectiveness of semi-empirical Brooks, Pope and Marcolini model and hybrid large eddy simulations in calculating the blunt trailing edge wind turbine noise at higher Reynolds number conditions. The 4 million element meshes of sharp and blunt trailing edge airfoils were tested at a Reynolds number of 3.2 million and an angle of attack of 4 degrees. The predicted airfoil self-noise by the modified semi-empirical formula with a low frequency directivity function and an additional term for large thickness ratio was compared to the experiments. The sound pressure level spectra from the hybrid large eddy simulation show that the predictions agree well with experimental measurements at the same observer location in the peak frequencies of the blunt trailing edge noise and sound pressure level rates of change at lower frequencies are also similar to experiments. The modified semi-empirical formula and the hybrid large eddy simulation can be considered as promising tools for high vorticity flow problems, especially for flatback airfoils for use on large wind turbines.     

风力机柔性叶片的仿生设计与性能

基于植物叶脉中轴对称结构的增强机理,提出了一种仿中轴图式拓扑结构的风力机柔性叶片设计方法,以20 kW风力机叶片为研究对象,采用实验测定和数值模拟的手段,从叶片失速特性和风能利用效率的角度对仿生设计叶片的柔性进行了研究.结果表明,仿生物中轴设计的叶片在极端风速下具有较低的内部载荷,桨叶失速状态下的柔性较强,能够明显拓宽风力机的正常运行风速范围,提高风能的利用效率.     

2MW风力发电机轮毂优化设计

优化设计是一种为了让自己的设计材料最省、支出最小的一种技术。通常,在设计中,会有许多的设计方案以供选择,如何从众多的方案中选择一个最好的方案,就需要有较好的设计方法。优化设计的方法有很多,而拓扑优化又称结构布局优化,是一种根据优化目标、载荷及约束而寻求结构材料最佳分配的优化方法。针对2MW风力发电机轮毂进行了拓扑优化,对比分析了优化前后轮毂的质量、及联合工况下的应力和变形,结果表明,联合工况下的应力及变形减小,动态应力最大值减小,动态强度提高;并在三维软件中重建模型,验证优化后模型进行工程实践的可行性。     

Offshore wind turbine blades measurement using Coherent Laser Radar

To maximize aerodynamic efficiency, large-scale offshore wind turbine blades require inspection during the production stage to ensure strict tolerance requirements are met. During production, the blade is fixed at the root, restricting movement in the Z direction. X, Y, Rx, Ry and Rz remain unconstrained causing blade flex due to gravity. This deforms the blade away from the theoretical CAD blade location, causing measurement results that do not accurately represent the blade profile. Measurement error can be minimized using rigorous B-spline data alignment. Such alignment compensates for blade flex by varying the constrained Degrees of Freedom (DoF), and provides manufacturers with confidence in the design process. This paper used Coherent Laser Radar and Spatial Analyzer to establish the optimal constrained DoF variation, giving the most accurate data alignment solution. Of the constraints investigated, the optimal data transformation solution was found with a double B-spline alignment method, whilst constraining movement in Y, Z and Ry.     

Load and dynamic characteristic analysis of wind turbine flexible blades

Aiming at the Megawatt (MW) scale wind turbine, a dynamic analysis and simulation method is presented to research blade loads and dynamic characteristics. To consider blade flexible deformation, the whole blade was divided into a number of units. Each unit was treated as a rigid body, the flexible connection between two adjacent units is considered. A nacelle coordinate system, a rotating shaft coordinate system, and a blade coordinate system were employed to describe the wind turbine blade. In those coordinate systems, blade inertial load calculation model, centrifugal force load calculation model and gravity load calculation model are established. Combining load model with the whole model of wind turbines, the real-time dynamic simulation model of blade loads was established in Simulink circumstance and a numerical simulation was performed. Based on the simulation analysis, some research results were obtained. When the large instantaneous fluctuation of electromagnetic torque of generator happens, rotor speed does not appear to have large fluctuation due to the inertia of the wind rotor, but the blade vibration speed changes obviously. Gravity has a periodic variation in the process of blade rotation and has a large influence on the edgewise moment. The research results provide a helpful reference for the structure design, operation, and control of wind turbines.     

风力发电机组轮毂结构优化

以中国自行设计的某MW级风机轮毂为研究对象,先对轮毂进行拓扑优化,验证拓扑结构,然后对轮毂进行自由尺寸优化,给出一种新型的轮毂结构,使得轮毂重量减少18.6%.优化后的轮毂不但节省材料的消耗,而且使得轮毂强度增加51.4%,疲劳寿命满足使用要求.     

Aerodynamic topology optimization on tip configurations of turbine blades

Journal of Mechanical Science and Technology - The topology optimization (TopOpt) is adopted in this article to design tip geometries of a turbine blade. Its principle is to modify the porosity,...     

3MW海上风力机叶片的三维建模及模态分析

叶片作为风力机的重要部件,对其进行合理的设计至关重要.研究了兆瓦级水平轴风力机叶片的设计流程,针对海上风电机组所处的复杂外部环境,选择合理的设计参数,设计出满足海上工作环境的3MW水平轴式风力机叶片;使用三维绘图软件,完成叶片的三维实体建模;运用有限元方法,选定叶片材料的特征参数,进行叶片的模态分析,确定了叶片的振型模态,并对比分析叶片各阶的振型模态结果.结果表示,该叶片的固有频率与外部激振频率不重合,避免了共振破坏的发生.     

风电叶片三维参数建模及振动分析

利用目前风力机叶片设计普遍采用的优化设计方法Wilson设计方法,通过MATLAB编程,开发了小型叶片气动设计的应用程序,并利用该程序设计了一台3kW小型水平轴风力机叶片.采用MATLAB和ANSYS共同建立了风力机叶片三维有限元参数模型,MATLAB编制的建模程序提高了初期设计效率,缩短了ANSYS分析前处理时间.在此基础上进行了叶片固有振动特性计算,分析了叶片的振动特性及其与结构参数之间的关系,分析方法和结果对风电叶片的结构设计和动力分析有一定的参考价值.