襟翼相对长度对翼型气动性能的影响

Effect of Relative Flap Length on Aerodynamic Performance of the Airfoil

以NACA0018为基准翼型,采用Fluent数值模拟方法对比研究了襟翼相对长度(分别取0.2、0.3和0.4)和翼缝相对宽度(分别取1.0%、1.5%和2.0%)对翼型流场结构及升、阻力特性的影响,并着重分析襟翼相对长度对翼型气动性能的影响.结果表明:由于襟翼对翼型周围主涡发展和变化的影响,不仅改善了翼型的失速特性,同时也提高了翼型的气动性能;襟翼翼型的失速攻角在研究范围内均大于基准翼型;在攻角小于失速攻角时,襟翼翼型的升力系数均小于基准翼型,阻力系数均大于基准翼型,但升力系数的最大值均大于基准翼型;随着襟翼相对长度的增大,翼型失速攻角逐渐减小;当攻角接近翼型失速攻角时,升力系数先增大后减小;襟翼相对长度相同时,随着翼缝相对宽度的增大,升力系数逐渐减小.

Taking the NCA0018 airfoil as the benchmark airfoil, the effects of relative flap length （0.2, 0.3 and 0.4） and relative slot width （1.0%, 1.5% and 2.0 %） on the airfoil flow field and resistance properties were numerically studied using Fluent software, with focus on the effects of relative flap length on the airfoil areodynamic performance. Results show that the existance of flap helps to not only improve the airfoil stall characteristics, but also improve the aerodynamic performance of the airfoil, due to its impact on development and variation of the main vortex around the airfoil. For flap airfoil, the stall angle of attack within the scope of study is greater than that of the benchmark airfoil, and when the angle of attack is less than the stall angle of attack, the lift coefficient of flap airfoil will be less that of the benchmark type, and both the drag coefficient and the maximum lift coefficient will be higher than benchmark airfoil. The stall angle of attack reduces gradually with the rise of reltive flap length. When the angle of attack is close to the stall angle of attack, the lift coefficient increases first and reduces later on. For a certain length of flap, the lift coefficient reduces with the rise of relative slot width.