襟翼长度对翼型水动特性影响

针对日益受到关注的潮流能水轮机中叶轮所用翼型水动力问题,采用CFD数值模拟方法,以NACA0018为基准翼型,对比分析了带襟翼翼型和原始翼型的流场变化,以及襟翼长度对翼型水动特性及表面静压力系数分布的影响。数值计算结果表明:襟翼可以使翼型失速攻角延后,且在达到失速攻角后可比原始翼型对应攻角时的升力系数有所提高;在小攻角下,襟翼对翼型压力分布影响较小,襟翼长度为0.3c(c为翼型弦长)时,压力系数改变最为明显;当攻角接近失速攻角时,襟翼长度为0.2c时,在所研究范围内,翼型水动特性最优;达到失速攻角后,襟翼对翼型流场及静压系数分布影响较大,翼型前缘吸力面低压区范围增大,压力面高压区范围均匀分布,且当襟翼长度为0.2c时翼型水动特性最优,其升力系数较原始翼型升力系数均有较大提升,阻力系数变化不大。

Effect of flap length on water dynamic characteristics of airfoil

Aimed at the problem of hydrodynamic for tidal current turbine,the paper used CFD numerical simulation method and took NACA0018 as reference airfoil to analyzed the change of flow field of original and wing airfoil, and the impact of flap length on dynamic characteristics and surface static pressure coefficient distribution of airfoil.Numerical results show that the flap airfoil stall angle of attack can be delayed, and after reaching the lift coefficient,the original wing stall angle corresponding to the angle of attack increased;the influence of flap on airfoil flap pressure distribution in a small angle of attack is less.When flap length is 0.3c (c the airfoil chord), the change of pressure coefficient is most evident;when the angle of attack approaches the smallest and flap length is 0.2c, the airfoil optimal hydrodynamic characteristics is optimal;after reaching the stall angle of attack,the influence of flap on wing flow field and static pressure coefficient distribution is greater.The distribution of pressure area range of airfoil suction surface is uniform.When the length is 0.2c the hydrodynamic characteristics is optimal.The lift coefficient has greater increase than that of original airfoil,but the resistance coefficient changes little.