【作者】 张庆麟；

【导师】 李宇红；

【作者基本信息】 清华大学 ， 动力工程及工程热物理， 2007， 硕士

【摘要】 准确的了解叶片的气动性能对指导风力机叶片的设计具有重要意义。本文针对准确求解风力机叶片气动性能这一问题,探讨了不同湍流模型及不同的近壁处理方法对风力机叶片绕流数值模拟结果的影响,对NREL PhaseⅥ实验风力机叶片在不同来流风速下的绕流流场进行了全三维数值模拟,分析了该叶片的气动性能,并对其气动特性进行了改进,最后提出了一种进一步改进风力机叶片气动性能的思想。研究工作具体内容和结论如下:本文采用有限体积法以及基于压力修正的SIMPLE方法,研究了计算域的大小对PhaseⅥ风力机叶片三维绕流数值模拟的影响,得到了合适的计算域,并在此基础上讨论了使用壁面函数的前提下,采用原始k-ω湍流模型和SST湍流模型对该叶片的气动性能进行数值模拟的可行性,发现壁面函数不能正确的模拟转捩过程的叶片绕流流场。直接采用密集网格求解近壁区的流动是另一类方法。本文采用该方法,配合SST湍流模型对PhaseⅥ风力机叶片三维绕流进行了数值模拟,并通过与实验结果对比证明了数值计算的可靠性。通过对PhaseⅥ风力机叶片吸力面表面流线、叶片截面附近流线和输出轴扭矩沿叶展方向的分布曲线的讨论,总结了PhaseⅥ叶片的气动特性。提出了通过改变叶片截面扭转角以改进叶片在不同风速下,尤其是在额定风速附近的出力特性的方法,并采用该方法对PhaseⅥ风力机叶片进行了修改。对新叶片气动特性的数值模拟表明,改进后的叶片的出力特性要优于原始叶片,尤其在额定风速附近,能较大的提高叶片出力。最后,提出了一种直接从叶片的三维数值模拟出发对叶片的气动性能进行进一步优化的思想。更多还原

【Abstract】 An accurate understanding about the aerodynamic characteristics of wind turbine blades can offer guidance on the design of wind turbine blades. Aiming at this subject, the essay probes for the effects of different turbulence models and near-wall treatment have made on the numerical simulation of the fluid field around a wind turbine blade. A three dimensional numerical simulation is carried on to imitate the fluid field around the NREL PhaseⅥwind turbine blade. In addition, some advice is offered on how to improve the aerodynamic characteristics of the PhaseⅥblade. The content and conclusion of the research are following:Finite volume method and SIMPLE method were used. The influence of the size of computational domain on the accuracy of numerical computation was researched, and a suitable computational domain was reaped. The possibility of using wall functions to simulating the fluid field around wind turbine blades with different turbulence model was researched, and the conclusion proved that wall functions can’t simulate the fluid field correctly, especially in the stall developing stage. Another method has been tried to imitate the fluid in boundary layer using low-Reynolds method. The SST model was used in the simulating, and the result was compared with the experiment result to prove the accuracy of this method.The aerodynamic characteristics of the PhaseⅥblade was analyzed, and a new way of improving the aerodynamic characteristics of wind turbine blades was put forward. the PhaseⅥblade was improved by using this method, and the result showed the aerodynamic characteristics of the new blade was better than that of the old one.更多还原