覆冰条件下风力机翼型气动性能的研究

AERODYNAMIC PERFORMANCE OF WIND TURBINE AIRFOIL UNDER ICING CONDITIONS

应用CFD软件,对几种典型覆冰形态的流场进行研究。分析结果表明:前缘覆冰改变了翼型的气动外形,使流动更易出现分离现象,造成升力减小,阻力增大,零升迎角i0增大。沿弦向生长的覆冰保持流线型的截面形状,对边界层流动影响相对较小;向上翼面或下翼面生长的覆冰可使该翼面边界层流动分离,造成翼型气动性能的下降。随着前缘覆冰长度的增加,覆冰可导致翼型的升力增加、失速滞后,这种现象类似于前缘襟翼效应。

The flow fields of some typical ice profiles are simulated numerically by using CFD code. Results showed that ice profile in the leading edge of airfoil lead to significant flow separation on the upper and lower surface due to change its geometry profile. The flow separation can result sharp rise in drag coefficient and lose in life coefficient which will enlarge its zero-lift angle. For the ice profile extended toward the chord of the airfoil, the ice keep streamlined shape, has little effect on boundary layer flow. For the ice profile extended toward the upper or lower surface, the ice leads to rapid growth of flow separation on this surface, which can result in performance degradation of it. With the acceleration of ice profile in the leading edge of airfoil, the C1,max increase and stall delay happen, just as the effects produced by leading-edge flaps.