水平轴风力机翼型动态失速特性的数值研究

INVESTIGATION ON AIRFOIL DYNAMIC STALL OFHORIZONTAL AXIS WIND TURBINE

动态失速对水平轴风力机的运行性能影响很大,大量的实验和分析显示,水平轴风力机在动态失速工况下其运行载荷将增长50～100%,而风力机翼型的动态失速特性是分析水平轴风力机动态失速特性的基础。本文应用CFD软件Fluent6 0对NRELS809翼型的二维动态流场进行了数值模拟,得到了翼型攻角在9°～31°范围内按正弦周期变化时的绕流流场。计算结果显示:动态失速下翼型的绕流流场与相同工况下的静态绕流流场有着十分明显的差别,同时也引起翼型升力、阻力系数的显著变化。

The dynamic stall has great impact on the operational performance of the horizontal axis wind turbine (HAWT). It has been proved by many experiments and analysis that the loading will increase 50-100% at the dynamic stall condition. The study on dynamic stall characteristics for HAWT is based on that for airfoil. The 2-D numerical simulation is employed to study the dynamic stall of the NREL S809 airfoil using the CFD software. The sinuous periodic flow field around the airfoil is presented when the angle of attack changing from 9° to 31°. The difference between the flow field under the dynamic stall condition and that at the static state is obvious, which makes the lift coefficient and drag coefficient varying distinctly. As a result, the output power of HAWT's rotor is increased significantly with dynamic stall. It will bring some unimaginable danger to the running of wind turbine, if dynamic stall is not considered during the design of HAWT.