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提出用壳梁组合结构有限元法计算扇形扭曲叶片组的固有频率和模态。对扭曲叶片采用8节点超参数壳体单元,对拉筋则用空间梁单元,讨论了壳梁这两类单元的对接方法。为提高计算精度和计算叶片组动频率,把叶片组振动作为物理线性、几何非线性的力学问题来处理,并考虑了组内叶片为扇形排列的几何特点。 相似文献
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为了满足自适应叶片的发展,文章提出了一种弧形叶片的参数化方法。该方法基于微分几何曲线理论,结合Bézier曲线和直叶片的参数化方法,达到了由控制点来控制弧形叶片几何外形的目的。基于弧形叶片的特点,将二维叶素理论转换到弧形叶片的截面上,并进行气动载荷计算,从而改进了叶素动量理论(BEM)。以NREL5MW风力机叶片为基准叶片,通过控制空间参考线控制向量可以得到具有预弯/扫掠特性的弧形叶片。结合改进的BEM理论和气动弹性理论,研究了该弧形叶片与参考叶片的气弹特性。研究结果表明:相比常规叶片,具有预弯/扫掠特性的弧形叶片能够有效地降低叶片的疲劳载荷和变桨载荷。该结果为设计具有减载功能的自适应叶片提供了一种可行的思路。 相似文献
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汽轮机叶片的材料特性、结构参数以及汽轮机转速都存在随机性,从而导致叶片的频率存在分散性,随机有限元方法可以考虑叶片参数的随机性,并得到频率的随机特征.将叶片的材料特性和结构参数处理为随机参数,基于随机变分原理推导了旋转叶片的随机有限元方程,建立了质量矩阵、线弹性刚度矩阵、几何刚度矩阵、动力刚度矩阵的均值和一阶变异矩阵,给出了固有频率均值、协方差和变异系数的计算方法.最后对432叶片的静动频率进行了随机有限元分析,定量给出了叶片参数随机变异导致频率的变异程度,为高可靠性叶片设计提供了分析工具. 相似文献
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以汽轮机叶片设计优化为对象,研究叶片设计优化中智能主模型技术及其内涵,采用参数化形状控制模型、设计知识描述模型、型线数据库、仿真分析模型以及特征/几何混合模型等表示叶片智能主模型,并基于叶片智能主模型,提出了叶片综合设计优化技术的实现途径. 相似文献
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针对大功率风电机组气动分析过程中叶素动量(BEM)理论计算精度不高、三维计算流体力学(CFD)仿真分析计算时间长的问题,以某5 MW风电叶片翼型数据为参考,分析不同风轮尺度下BEM与CFD的计算精度和效率;基于几何相似、运动相似和动力相似理论,推导缩比模型与原型之间的几何、运动、力学参数的比例关系,比较不同几何比例尺下风电叶片的气动性能;以几何比例尺为参考,建立大尺度风轮高精度缩比模型,分析多种工况下缩比模型CFD仿真的计算精度与效率。研究结果表明:风轮尺度越大,CFD与BEM分析的结果相对差值越大,多种工况下大尺度风轮缩比模型气动性能基本与原型保持一致,但计算效率获得大幅提升。 相似文献
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This paper presents a method for decoupled design of bend-twist adaptive blades (BTABs) in which the aerodynamic and structural designs take place separately. In this approach the induced twist is considered as an aerodynamic design parameter, whilst its dependency on the structural characteristics of the blade is taken into account by imposing a proper constraint on the structure design. The main advantage of this method is the significant reduction in evaluation time by replacing a finite element analysis (FEA)-based coupled-aero-structure (CAS) simulation in the aerodynamic objective evaluation by a non-FEA-based CAS simulation. Through a re-design case study an ordinary blade has been converted to a BTAB and the efficiency of the method in performing decoupled design of BTABs has been illustrated. 相似文献
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Application of combined analytical/FEA coupled aero-structure simulation in design of wind turbine adaptive blades 总被引:3,自引:0,他引:3
This paper demonstrates the application of combined analytical/FEA coupled aero-structure simulation in design of bend-twist adaptive blades. A genetic algorithm based design tool, in which the power curve is predicted through a combined coupled aero-structure simulation, has been developed. A bend-twist adaptive blade has been designed to be used on the rotor of a constant speed stall regulated wind turbine. The bend-twist adaptive blade is assumed to be made out of anisotropic composite materials. The designed blade has the same aerofoil and chord distribution as the original blade used on the wind turbine, but with a different pre-twist distribution. The simulated results show a significant improvement in the average power of the studied stall regulated wind turbine when employing the designed adaptive blades. 相似文献
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On the role of surface roughness in the aerodynamic performance and energy conversion of horizontal wind turbine blades: a review
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Iham F. Zidane Khalid M. Saqr Greg Swadener Xianghong Ma Mohamed F. Shehadeh 《国际能源研究杂志》2016,40(15):2054-2077
Renewable energy is one of the main pillars of sustainable development, especially in developing economies. Increasing energy demand and the limitation of fossil fuel reserves make the use of renewable energy essential for sustainable development. Wind energy is considered to be one of the most important resources of renewable energy. In North African countries, such as Egypt, wind energy has an enormous potential; however, it faces quite a number of technical challenges related to the performance of wind turbines in the Saharan environment. Seasonal sand storms affect the performance of wind turbines in many ways, one of which is increasing the wind turbine aerodynamic resistance through the increase of blade surface roughness. The power loss because of blade surface deterioration is significant in wind turbines. The surface roughness of wind turbine blades deteriorates because of several environmental conditions such as ice or sand. This paper is the first review on the topic of surface roughness effects on the performance of horizontal‐axis wind turbines. The review covers the numerical simulation and experimental studies as well as discussing the present research trends to develop a roadmap for better understanding and improvement of wind turbine performance in deleterious environments. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献