鸭翼对BWB飞机低速纵向气动特性的影响

Low-speed longitudinal aerodynamic influence of canard on BWB aircraft

采用近距鸭翼的概念以解决翼身融合布局(BWB)飞机低速低头力矩过大问题,通过对带有不同安装位置和平面形状鸭翼的BWB飞机开展数值模拟研究,分析低速下鸭翼影响BWB飞机气动性能的流动机理,以及升力和力矩方面的收益。研究表明:在大迎角下,鸭翼使BWB飞机内翼段在涡核破裂后仍能形成稳定的集中涡并保持较高强度,增加BWB飞机本身的失速迎角,提升了该布局大迎角下的升力以及抬头控制能力;且鸭翼对BWB布局飞机气动性能的影响与鸭翼位置及其形状紧密相关,相对位置较高的鸭翼可以与BWB飞机本体之间产生更为有利的干扰,达到增升与抬头效果,而鸭翼后掠角越小,越有助于提升BWB飞机的纵向操纵及配平能力。该研究成果可为BWB飞机在未来民机领域的预研和发展提供一定的理论参考。

The concept of a close canard wing is proposed in the first part of this paper for improving the poor performance of the Low-speed Blended-wing-body(BWB)in longitudinal control and trim.For different positions and shapes of the canard,the aerodynamic performance is investigated respectively by numerical simulation,and the flow mechanism that effect the lift and moment of the BWB configuration is analyzed.The result shows that,for the BWB configuration,the canard can keep the canard vortex stable with high intensity after the vortex core of the BWB inner wing breakdowns at high attack angle,leading to the increment of the stall angle of BWB configuration,so that a higher lift and pitch up control capability can be achieved.The result also shows that the improvement of aerodynamic efficiency has a close relationship with the position and geometry of the canard.A sweep back canard with a high position and short distance can produce favorable interference with the BWB wing,which is helpful to advance the longitudinal control and trim capability.The results of the article can provide certain theoretical references for the advanced research and development of the BWB configuration in the future commercial study.