超椭圆S形进气道的设计及气动性能研究

Designof Super-elliptic S-shaped Inlet and Analysis of Aerodynamic Performance

研究飞机机身外形及进气道优化问题,传统的超椭圆方法在设计S形进气道时,形状指数n的选取需要查表来确定,不仅耗时,而且精确度不高,容易产生面积突变,对进气道内流和出口截面的总压影响很大。将形状指数n和S形进气道的截面面积变化规律联系起来,为提高指数的准确性和效率,提出一种改进的超椭圆S形进气道设计方法,以自适应的方式确保任意截面指数n的准确性和唯一性。数值仿真表明:改进的方法给出的S形进气道总压恢复系数较高,畸变指数较小,气动性能良好,改进的自适应超椭圆S形进气道设计方法具有较高的工程实用价值。

Generally, the shape index n is selected in a form when design an S-shaped inlet by traditional super -ellipse method. Unfortunately, this selection process is time-consuming and not precise enough, so the cross-section of the inlet designed by super-ellipse method may get distortions easily, which will influences the inner flow and the outlet total pressure of the inlet greatly. This paper associates the shape index n with the variation pattern of the inlet cross-section, and an improved super-ellipse method is developed to design the S-shaped inlet. This method ensures the precise and unique of shape index n in any cross-section by adaptive way. The result of the numerical simulations shows that the total pressure recovery coefficient of the S-shaped inlet using this method is high, the the distortion coefficient is low, and the aerodynamic performance is excellent. The analysis shows that this improved super-ellipse method by the adaptive way can be used in the real engineering.