文档介绍：摘要
本文针对国家科技支撑计划子课题“风电机组叶片气动优化设计和结构动力分析”, 探讨了能满足风力机叶片气动、结构和稳定性要求的多目标优化方法。通过对不同展向上翼型的相对厚度、弦长等外形参数的优化计算,得到了能使功率利用系数Cp值达到预定目标的气动优化设计结果;考虑结构和制造工艺性要求,修正了气动外形。并对优化后的叶片进行了载荷计算,使叶根载荷得到了降低,并对其进行强度分析。论文的主要内容如下:
综合考虑叶片气动性能和载荷情况,即除要保证风力机叶片有良好的气动外形之外,还要兼顾稳定性和结构强度等性能指标,对叶片的整体性能进行多目标优化。叶片的优化设计,是以叶片各展向截面的相对厚度、弦长和扭角为设计变量,建立了多目标优化的数学模型。基于遗传算法思想并利用MATLAB软件,实现了叶片的多目标优化设计。同时,,并与已运行的某商用机型做出对比,以验证该方法的有效性。
在FLUENT软件的GAMBIT前处理模块中建立了叶片的三维实体模型,并将建好的风力机叶片模型导入ANSYS软件中进行了模态分析,针对玻璃钢/复合材料的特点进行单元网格划分、施加一定的约束,得到前十阶振型的频率和振型。同时,研究了科里奥利力对叶片模态分析的影响。
基于GL坐标系,计算了风力机稳态下的气动力、重力、离心力;,借助于Bladed for Windows软件,计算了叶片上关键截面处的载荷。并找出根部的最大载荷,在ANSYS软件中进行有限元分析,得出此载荷作用下的变形图及应力云图。安全系数确定后,对其进行静强度校核。
根据IEC61400-1:1999标准,,分别计算出各工况下的载荷,在Bladed for Windows软件的后处理模块中提取出最大载荷及其所对应的工况,可据此对风力机叶片的强度进行校核。
关键词:风力机叶片;多目标优化; 结构动力学;模态分析;强度校核
Abstract
This paper belongs to National Key Technologies R&D Program -------- Aerodynamic optimization design and structure dynamic analysis of wind turbines blade. To meet the requirements of the aerodynamics, structure and stability, multi-objective optimization methods of HAWT blades have been developed. Through optimizating the shape parameters in the different distance from blade root, such as, relative thicknesses, chord lengths and torsion angles of the airfoils, the aerodynamic design optimization results that a power utilization factor Cp reached the intended target could be got. Finally, considering some requirements of structure and manufacturing process, aerodynamic shape was revised. After optimizing HAWT blades, load calculations were carried through to decrease the loads of the root. And on the basis of loads calculation, there was strength analysis on HAWT blades. The main contents were as follows:
The design objective was to find blade shape such that maximizing power utilization factor as well as decreasing the loads. Considering aerodynamic performance and loads, multi-objective optimization of the blade was carri