襟翼翼缝结构改进设计控制流动分离的数值研究

Numerical Investigation on Flap Gap Configuration Modification to Control Flow Separation

翼缝是翼型主体与襟翼之间的缝隙,对翼型气动性能与流场结构有很大影响。以两段式NACA0018翼型为基础翼型,对传统弯曲翼缝进行改进设计与数值模拟,以期增大失速攻角及改善在大攻角下的气动性能。结果表明：在小攻角下,导叶翼缝襟翼翼型的升力较原始NACA0018翼型小,阻力较大,但在大攻角下,导叶翼缝可减小翼缝中流体的速度损失,为翼型上表面边界层提供更多动能,从而改善流场结构及失速特性,弯曲翼缝可增大1°失速攻角,而导叶翼缝可增大8°,攻角为18°时升力系数较弯曲翼缝提升43%。因此,导叶翼缝可极大地改善翼型在大攻角下的气动性能。

Abstract： Gap is the slot between main body and flap which greatly influences aerodynamic performance and small flow structure. Based on the two-element NACA0018 airfoil, for enhancing the ability to rise stall angle and aerodynamic performance of airfoils, the gap configuration was modified and numerically investigated. Results indicate that although modified guide-blade gap configuration leads to lift reduction and drag increase, the ability to delay flow separation was stronger and it decreases the velocity loss in the entrance of gap. The modified guide-blade gap increases the stall angle by 8°, compared to 1°of the origi- nal gap. Furthermore, the lift coefficient is increased by around 43 %. Thus, the modified guide-blade gap significantly improves the aerodynamic performance of airfoil at high angle of attack.