具有自振簧(膜)片的风电叶片流动分离抑制机理研究

Wind energy has become one of the world's fastest developing renewable clean energy. Therefore, it is very important to research the energy capture mechanism of the wind turbine and improve the utilization rate of wind power. Because of the long blade and big weight for the larger wind turbines, so in order to meet the required strength, the relatively large thickness of airfoil shape must be chosen between the blade root and the blade middle portion. However, even if a variable-speed variable pitch control mechanism is used for this kind of blade, some parts of the angle of attack still can be very large, thus flow separation can be hardly avoided. This project put forwards using elastic vibration modes of reed (film) installed on the suction side of the blade of wind turbine to excite the vibration of the reed (film) piece by the fluid pulsation, so as to realize the interference to unsteady flow field. As long as the size of the elastic reed (film), the location installed and its inherent frequency set is proper, flow separation on the airfoil suction with large angle of attack can be slow down or controlled, then improve the lift-to-drag ratio of the airfoil. The project will use high accuracy numerical simulation method and choose the proper turbulence model to study the mechanism of elastic reed (film) piece for delaying or controlling flow separation characteristics, and verify the analysis results through the wind tunnel experiments.

风能已成为当今世界发展最快的可再生清洁能源。研究风力机的能量捕获机理，提高风能利用率具有十分重要的意义。由于大型风电机组的叶片长、重量大，为了满足强度要求，叶片根部到中部之间必须选用相对厚度较大的翼型。对于这类叶片，即使采用变桨或变速等调控措施，某些部位的攻角仍然可能很大，流动分离难以避免。本项目提出了一种安装于风电叶片吸力面某一位置上的弹性自振簧(膜)片，流体的脉动会激起该弹性自振簧(膜)片的振动, 从而实现对流场的非定常干扰,只要弹性自振簧(膜)片的尺寸、位置及其固有频率设置得当，就可以延缓或控制大攻角下翼型吸力面的流动分离，提高翼型的升阻比。本项目将应用高精度的数值模拟方法，选用适当的紊流模型，研究这类弹性自振簧(膜)片延缓或控制流动分离的机理，获得弹性自振簧(膜)片的尺寸、位置及其固有频率对流动分离特性的影响规律，并通过风洞实验进行验证。

风能已成为当今世界发展最快的可再生清洁能源。研究风力机的能量捕获机理，提高风能利用率具有十分重要的意义。由于大型风电机组的叶片长、重量大，为了满足强度要求，叶片根部到中部之间必须选用相对厚度较大的翼型。对于这类叶片，即使采用变桨或变速等调控措施，某些部位的攻角仍然可能很大，流动分离难以避免。本项目提出了一种安装于风电叶片吸力面某一位置上的弹性自振簧(膜)片，流体的脉动会激起该弹性自振簧(膜)片的振动, 从而实现对流场的非定常干扰。项目研究发现：只要一定柔性的薄膜，当尺寸合适、安装位置合适时，能够激发特定频率的振动，可以延缓或控制大攻角下翼型吸力面的流动分离，提高翼型的升阻比。本项目应用高精度的数值模拟方法，选用适当的紊流模型，研究这类柔性膜片延缓或控制流动分离的机理，获得柔性膜片的尺寸、位置及其固有频率对流动分离特性的影响规律，再利用风洞试验，证明这种设想是可行有效的。