飞翼无人机保形进气道耦合进口格栅气动与隐身综合特性

基于飞翼无人机(UAV)保形进气道和工程应用实例,进行了不同格栅间距的格栅设计。结合多层快速多极子方法(MLFMM)和混合网格计算方法,开展了保形进口格栅气动和隐身综合特性研究。结果表明:①随着格栅尺寸（间距)减小,格栅隐身效果逐渐增强;频率为1GHz下,格栅间距为波长的1/3时,格栅电磁屏蔽效率约为48.93%,而当格栅间距达到波长的1/6时,接近于完全屏蔽;②保形进口格栅对无人机翼面上流动干扰较小而对进气道内流特性影响明显;③随着格栅尺寸减小,全机升阻特性逐渐略微下降,进气道出口截面总压恢复逐渐降低而畸变指数逐渐增大。 

Aerodynamic and stealthy integrated performance of conformal inlet coupling entrance grille of flying wing unmanned aerial vehicle

Based on the conformal inlet of flying wing unmanned aerial vehicle (UAV) and the relevant engineering application, grilles with different grille hole spacing were designed. Research on the integrated design of aerodynamic and stealthy performance was carried out based on multilevel fast multipole method (MLFMM) and the numerical simulation with hybrid grid. Results indicated: (1) With the decrease of grille hole spacing, the electromagnetic shielding effectiveness increased gradually; at the frequency of 1GHz, the electromagnetic shielding effectiveness can reach to about 48.93% when the grille hole spacing was λ/3(λ represents wavelength), and it would be shielded entirely while the grille hole spacing reached λ/6; (2) The conformal inlet grille generated a little influence on the fluid flow of wing surface of the flying wing UAV, but it had greater influence on the internal flow of inlet; (3) With the decrease of grille hole spacing, the lift/drag characteristic of flying wing UAV declined appreciably, while the total pressure recovery coefficient decreased and the distortion coefficient increased.