Effects of Geometrical Parameters of Internal Blown Flap and Its Optimal Design

内吹式襟翼几何参数影响研究与优化设计

School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China

Received: 10 January 2019

Abstract

The internal blown flap was numerically simulated. Firstly, a parameterization method was developed, which can properly describe the shape of the internal blown flap according to such geometrical parameters as flap chord length, flap deflection, height of blowing slot and its position. Then the reliability of the numerical simulation was validated through comparing the pressure distribution of the CC020-010EJ fundamental generic circulation control airfoil with the computational results and available experiment results. The effects of the geometrical parameters on the aerodynamic performance of the internal blown flap was investigated. The investigation results show that the lift coefficient increases with the increase of flap chord length and flap deflection angle and with the decrease of height of blowing slot and its front position. Lastly, a method of optimal design of the geometrical parameters of the internal blown flap was developed. The design variables include flap chord length, flap deflection, height of blowing slot and its position. The optimal design is based on maximum lift coefficient, the angle of attack of 5 degrees and the design constraint of stall angle of attack of less than 9 degrees. The optimization results show that the optimal design method can apparently raise the lift coefficient of an internal blown flap up to 1.7.

摘要

采用数值模拟方法对内吹式襟翼进行了研究。首先，开发了一种针对内吹式襟翼的参数化方法，该方法可以根据襟翼弦长、偏角、吹气缝高度、位置这些几何参数很好地描述其外形。然后，通过与CC020-010EJ标模的试验压力分布进行对比，验证了所采用数值模拟方法的可信度。分别研究这些几何参数对内吹式襟翼气动性能的影响，研究结果表明：襟翼弦长越长、偏角越大、吹气缝越窄、位置越靠前，翼型的升力系数越大。最后，构建了一种针对内吹式襟翼几何参数的优化设计方法。在固定吹气动量系数的基础上，以襟翼弦长、偏角、吹气缝高度、位置这些几何参数为设计变量，以5°迎角升力系数最大为优化目标，以失速迎角不小于9°为设计约束，开展优化设计。优化结果表明，优化设计方法可以显著提高内吹式襟翼的升力系数，升力系数的提高量达到1.7左右。