基于鸮翼特征提升风力机叶片气动性能的研究

Research on Improving Aerodynamic Performance of Wind Turbine Blades Based on Owl Wing Characteristics

为了提高风能利用率,研发气动性能优异的叶片,以模仿鸮翼生物特征来提升大型风力机叶片的气动性能。选择以NREL 5MW风力机的叶片作为研究对象,基于生物翼型和传统翼型构建了组合翼型,并将其与鸮翼的非光滑前缘结构耦合,设计了具有这两种特征的仿生耦合叶片。根据相似理论,建立原型叶片和仿生耦合叶片的缩比模型,并通过数值计算方法探究仿生耦合叶片在不同风速下的气动性能。数值计算结果表明,相比原型叶片,在额定风速11.4m/s时,仿生耦合叶片的风能利用率提高了6.76%,当风速达到15m/s时,仿生耦合叶片的扭矩提高9.89%。在叶尖区域,仿生耦合叶片吸力面流速明显增强,增大了吸力面负压区域面积,进而增大了叶片表面压差。同时,仿生耦合叶片能够有效抑制展向流动,减小尾缘分离涡,增强弦向流动,降低湍动能强度,减小了能量的损耗。

In order to improve wind energy utilization and develop blades with excellent aerodynamic performance,this paper takes the blades of the NREL 5MW wind turbine as the research object to improve the aerodynamic performance of large wind turbine blades by imitating the biological characteristics of owl wings.A combined airfoil was constructed based on the biological airfoil and the conventional airfoil and coupled with the non-smooth leading edge structure of the owl wing to design a bionic coupling blade with both characteristics.Based on the similarity theory,the scaled-down models of the prototype blade and the bionic-coupled blade are established.Numerical calculation methods were used to investigate the aerodynamic performance of the bionic coupled blade at different wind speeds.The results show that compared to the prototype blade,the wind energy utilization of the bionic coupled blade is improved by 6.76% at a rated wind speed of 11.4 m/s,and the torque of the bionic coupled blade is improved by 9.89% at the wind speed reaches 15 m/s.In the tip region,the flow velocity of the suction surface of the bionic coupling blade is enhanced,which increases the area of the negative pressure region of the suction surface and thus increases the pressure difference on the blade surface.At the same time,the bionic coupling blade can effectively suppress the spreading flow,reduce the trailing edge separation vortex,enhance the chordal flow,reduce the turbulent kinetic energy intensity,and reduce the energy loss.