风电机组内叶展多涡耦合机理与涡尾迹模型研究

There are complex root vortex and hub vortex existed in the inboard zone of horizontal axis wind turbine, which have important effect on the aerodynamic efficiency，control and wind power prediction. Unlike the tip vortex, their distributions are disperse and highly dependent on the wind turbines' operation parameters and geometry parameter of inboard blade and hub; also in turn have impact on the flow around the inboard blade. Under rotation case, the spanwise flow and stall delay around the blade root zone show distinct three dimensional characters, resulting the lift enhancement. In this project, three ways include experimental, computational and theoretical methods will be selected. The the origin, the development and the effect of the aerodynamic performance of the vortex near the root region will be investigated to obtain the vortex generation mechanism and how to be affected by the operation/geometry parameters. Then the vortex identification method and the validation among the three ways will also be established to establish the wake model in the near wake. Finally the correction model of rotation on the aerodynamic performance should be set up. The results will provide support to enhancing the aerodynamic performance, optimization of control and also the accurate prediction of aerodynamic performance of wind turbine.

水平轴风力机内叶展及机舱附近存在复杂的叶根涡和机舱涡，对风力机气动性能、调节/控制及功率预测有着不可忽视的影响。同叶尖涡不同，它们的分布较为零散，形成和发展过程高度依赖于风轮运行参数和内叶展及机舱几何参数，并对来流风和叶片内叶展流动产生影响。在旋转状态下，叶片绕流具有显著的三维流动特性，径向流动与延迟失速并存，使得翼型出现升力升高现象。本课题拟通过理论推导、数值模拟和实验的手段，对叶根和机舱附近的涡系的产生、发展进行研究，揭示不同涡系的产生机理及气动参数/几何参数对其影响规律；通过理论推导、数值模拟和实验数据中涡识别方法及三者之间的相互验证，建立近尾流区内叶展涡尾迹模型；通过构建几何参数、气动参数和性能参数数据库，完善不同涡系对风力机气动性能影响的数学模型。课题的研究结果可为提高内叶展流动效率、调节/控制及风功率预测提供依据。

水平轴风力机内叶展及机舱附近存在复杂的叶根涡和机舱涡，对风力机气动性能、调节/控制及功率预测有着不可忽视的影响。为此，本课题对机舱对内叶展圆柱段、内叶展翼型段气动性能的影响进行了研究，并对风力机的气弹特性和颤振特性进行了计算。本科课题开展的研究内容具体如下：（1）机舱形状对内叶展流动的影响。分别对带有真实机舱和简化机舱的风轮进行了数值模拟，结果表明二者对风轮气动性能及叶根圆柱段流动并无明显影响，与此相反，计算中的网格分布对结果有着较大的影响。（2）对内叶展翼型段部分，风轮的旋转会对翼型的气动特性产生明显的影响，课题提出了基于数值计算结果和神经网络的翼型延迟失速模型。通过该模型，可对失速延时进行有效的修正，修正精度与数值模拟的精度相同。（3）基于升力线/动量叶素理论和几何精确梁理论对气弹耦合下的风力机特性进行了预测，主要预测了极端风切变情况下的风轮气动性能。（4）基于上述的气弹耦合特性计算方法，对大型风力机的颤振时的挥舞、摆振频率和相位、位移响应及气动性能等进行了详细的分析，并进一步比较了质心位置、扭转刚度和结构阻尼等因素对颤振风速的影响。分析表明：当质心位置前移扭以及扭转刚度、结构阻尼、桨距角增大时，颤振风速增大，反之则减少。