翼型失速及雷诺数变化对风力机气动性能影响的数值研究

NUMERICAL RESEARCH OF THE INFLUENCE OF AIRFOIL STALL AND REYNOLDS NUMBER CHANGE ON WIND TURBINE AERODYNAMIC PERFORMANCE

利用数值模拟的方法,研究了翼型失速及风速变化引起的雷诺数改变对风力机气动性能的影响。数值计算将k-ω的SST湍流模型与单方程的SA模型结合使用,以模拟大攻角范围的翼型绕流。结果显示:随攻角增大,上翼面分离会依次经历尾缘分离涡与前后缘交替脱落分离涡两个阶段,后者依据分离涡对下翼面压力分布有无影响又呈现两种不同情况,使得不同攻角范围失速时的流场形态及对气动性能的影响存在很大差异;雷诺数变化主要影响上翼面前后缘出现交替脱落分离涡时的攻角区域,且雷诺数越大,其变化引起的升阻系数变化越小。

Numerical simulations were carried out to study the effect of airfoil stall and Reynolds number change caused by wind velocity variation on wind turbine aerodynamic performance, κ-ω SST turbulence model was combined with SA model to adapt to the numerical simulation of flow around airfoil in large attack angle range. The results showed that uppersurface separation, as attack angle increases, go through two stages： trailing edge separated vortex and alternately shedding separated vortex of leading and trailing edge. And the later can be divided into two types according to whether the Separated Vortex affect pressure distribution of the airfoil lower surface. As a result, there are different flow field forms and aerodynamic performance influence in different attack angle range at stall. The change of Reynolds number mainly influences the attack angle range in which leading and trailing edge separated vortex alternately shed. The larger the Reynolds number, the smaller the lift and drag coefficient change caused by the change of Reynolds number.