悬停状态下倾转旋翼机向下载荷被动减缓措施研究

Strategies for tiltrotor aircraft download reduction in hover using passive flow control

基于SA一方程紊流模型的DES方法,发展了一种翼型在-90°来流迎角下非定常大分离流动的数值模拟方法,系统地研究了后缘襟翼、克鲁格襟翼、前缘下垂以及扰流板四种被动控制技术在悬停状态下倾转旋翼机向下载荷减缓中的应用,并分析了各影响参数对阻力系数的影响。计算结果表明:当后缘襟翼偏角60°时,垂直阻力最小;克鲁格襟翼偏角85°时,阻力系数最小;前缘下垂偏角45°时,阻力系数最小;当扰流板高度h/c=0.05时,阻力系数最小。最优组合构型为后缘襟翼偏角60°,克鲁格襟翼偏角85°,其向下载荷相对于原始翼型减小了55.4%。

A numerical study solving the Navier-Stokes equations for the unsteady massively separated flows around an airfoil section at-90°angle of attack is performed based on the SA-DES approach.Four passive flow control strategies,namely trailing edge flap,Kruger flap,droop-nose and spoiler are used to research the download（vertical drag）reduction for tiltrotor aircraft in hover.The effects of different factors are also discussed.The results indicate that when the trailing edge flap deflection angle is 60°,the airfoil has the minimum download;the minimum downloads of configurations with the Kruger flap,the droop-nose and the spoiler are generated at a Kruger flap angle of 85°,a droop-nose deflection angle of 45°,and a height-to-chord ratio of h/c=0.05,respectively.The results show that the drag of the optimal assembly configuration,with a trailing edge flap deflection angle of 60°and a Kruger flap angle of 85°,is reduced by55.4% compared with the basic airfoil.