后缘襟翼对NACA0018翼型性能影响的数值研究

Numerical Investigation of the Influence of Trailing Edge Flap on the Performance of NACA0018 Airfoil

摘要: 针对NACA0018厚翼型在Re = 1.38 × 105下安装不同高度格尼襟翼与锯齿襟翼对翼型气动性能影响进行数值模拟研究。比较原始翼型和2%，4%，6%弦长高度的格尼襟翼与锯齿襟翼的气动性能，同时对襟翼后尾迹流场结构进行分析。结果表明，格尼襟翼的增升效果随襟翼高度的增加而增加，但是当高度达到6%c时由于阻力的急剧增大，升阻比降低，而在6%弦长的襟翼高度内，锯齿襟翼升阻比随高度的增加均有所增大，6%c的锯齿襟翼性能最佳。格尼襟翼开锯齿后，气体通过锯齿后会在齿根与齿尖分别形成两对方向相反的旋涡，此旋涡与格尼襟翼产生的脱落涡掺混耗散，使脱落涡很快消失，削弱由于格尼襟翼后产生旋涡而引起尾流的不稳定性，从而减小了翼型的阻力，提高升阻比。

Abstract: The numerical simulation of the aerodynamic performance of NACA0018 thick airfoil with different height of Gerney flaps and serrated flaps at Re = 1.38 × 105 was carried out. The aerodynamic performance of the original airfoil was compared with that of the Gueney and the serrated flaps of 2%, 4% and 6% chordlength height, and the flow field structure in the wake of the flaps was ana-lyzed. The results show that the lifting effect of the Gurney flaps increases with the increase of the height of the flaps, but the lift to drag ratio decreases when the height of the flaps reaches 6%C due to the sharp increase of the drag. The SGF lift to drag ratio increases with the increase of the height of the flaps of 6%C chord, and the SGF performance is the best at 6%C chord. After passing through the serrated tooth, the fluid forms two pairs of vortexes in opposite directions at the root and the tip of the sawtooth respectively, this vortex is dissipated by mixing with the shedding vortex generated by the Gurney flaps, make the shedding vortex disappear quickly. It reduces the wake instability caused by the vortices behind the Gurney flaps, thus reducing the drag of the airfoil and increasing the lift-drag ratio.