前缘辅助小翼对风力机翼型气动性能的影响

Effects of leading edge auxiliary airfoil on aerodynamic performance of wind turbine airfoil

基于SST k-ω模型,分析了前缘添加辅助小翼后,在2°~22°攻角下对主翼S809翼型的气动特性的影响.结果表明,在小攻角2°~6°下,主翼的升力减小,阻力增加,但当攻角达到8°时,前缘辅助小翼使得主翼升力增加,阻力减小,升阻比增大.通过分析主翼在10°、14°、18°和22°大攻角下的流动分离规律和增升机理,表明前缘辅助小翼的存在有效抑制和延迟了流动分离,有效抑制了分离泡,从10°和18°的涡量云图可以看出,前缘辅助小翼上产生的涡对主翼涡有明显的抑制效果.计算提取了在14°、18°攻角下翼型吸力面不同高度的x方向速度,在边界层内相同高度的x方向速度分量值大于原始翼型的,表明沿翼型表面x方向流体拥有更大的动能,有助于主翼在大攻角下提高气动性能.

S809 is used as the main airfoil and an auxiliary airfoil is added at its leading edge.Based on the SST k-ωmodel,the effect of the auxiliary airfoil on the aerodynamic characteristics of the main airfoil S809 at the angle of attack from 2°~22°are analyzed.The results show that when the leading edge auxiliary airfoil is added at the leading edge of the main airfoil,the lift force of the main airfoil is decreased and the drag force is increased at a small angle of attack of 2°~6°.However,when the angle of attack reaches 8°,the leading edge auxiliary airfoil increase the lift force of the main airfoil,the drag force is decreased and the lift-drag ratio is increased.The flow separation law and the lifting mechanism of the main airfoil at 10°,14°,18°and 22°are analyzed.The existence of leading edge auxiliary airfoil effectively inhibits and delays flow separation,and effectively inhibits separation bubbles at large angles of attack.As can be seen from vorticity cloud images of 10°and 18°,the vortex generated at the leading edge auxiliary small airfoil has an obvious inhibition effect on the main airfoil vortex.In the boundary layer,the x-direction velocity component at the same height is larger than that of the original airfoil,which indicates that the fluid along the x-direction of the airfoil surface has greater kinetic energy,which is helpful to improve the aerodynamic performance of the main airfoil at large angles of attack.