排翼布局飞行器气动性能的实验研究

通过低速低湍流度风洞实验,研究了利用排翼布局改善充气飞机采用大厚度翼型机翼带来的气动效率偏低问题。首先比较了采用不同厚度翼型的单翼与排式双翼布局的气动特性。在此基础上,为了优化排翼布局的气动特性,研究了给后翼安装偏转角对排翼布局气动特性的影响。同时,基于NACA0030翼型,设计了波纹型外形的充气机翼,比较了此外形下单翼和排翼布局气动性能的差异。实验结果表明,采用排翼布局能够改善采用厚翼型单翼布局的气动性能,而给后翼安装一定偏转角可以进一步提高排翼布局的升力和升阻比。采用波纹外形和光滑外形机翼模型的对比结果表明,波纹外形能够在大迎角时改善充气机翼的失速性能。分析认为,造成这一现象的流动机理是由于波纹型机翼在实验条件下提前由层流转捩为湍流,使失速推迟,流动分离现象有所减弱。

Experimental Investigation on the Aerodynamic Characteristics of Row-Biplane Aircraft

A new row-biplane configuration designed to improve the low aerodynamic efficiency of inflatable aircraft adopting large thickness airfoil was investigated by means of low speed and low turbulence wind tunnel experiment. The effect of airfoil thickness on aerodynamic performance of monoplane and biplane was compared firstly, based on which, in order to optimize the performance of new configuration, the effect of deflection angle mounted on posterior wings of biplane on the aerodynamic performance was investigated. Meanwhile, based on NACA0030 airfoil, an inflatable wing with corrugated profile was designed and the performance of monoplane and row-biplane with corrugated profile was compared. Experimental results show that comparing with monoplane with thicker airfoil, the aerodynamic characteristics of row-biplane are greatly improved, and the deflection angle mounted on posterior wing may further enhance the lift and lift-drag ratio of new row-biplane configuration. Furthermore,the comparison between models with smooth profile wing and corrugated profile wing indicates that the stalling characteristics of corrugated profile at high attack angles may be notably improved, due to the flow mechanism that under experimental condition, early transition from laminar to turbulent flow appears for corrugated profile, which delays the stalling and weakens the flow separation.