通用直升机隐身气动外形综合设计

Utility helicopter design synthesison of stealth and aerodynamic configuration

对某型通用直升机进行隐身气动外形综合设计并对其参数化建模,通过数值模拟分析其隐身气动特性。电磁方面,采用物理光学法结合等效电磁流法进行RCS(Radar Cross Section)计算;气动方面,采用有限体积法求解Navier-Stokes方程计算直升机机身前飞状态下(不考虑旋翼气动干扰)的气动特性,结合工程经验公式估算旋翼对机身的气动干扰。结果表明:综合设计后,直升机雷达散射水平相对较低,机身前飞阻力得到较大的改善,但旋翼对机身的干扰作用有所增加;机身侧面(和垂尾)的倾角增大对直升机隐身特性有利,但对气动性能带来不利影响;选择合适的倾角可以使直升机在付出相对较小的气动代价前提下,降低雷达散射水平。

Based on a conventional utility helicopter, design synthesis scheme on stealth and aerodynamic configuration was proposed. The parametric geometric model of the modified heli- copter was established. And numerical simulation was performed for design analysis. In terms of electromagnetic analysis, physical optics and the method of equivalent currents were used for ra- dar cross section （RCS） calculation. In terms of aerodynamics, the finite volume method was used by solving Navier-stokes equations to calculate the aerodynamics of fuselage in forward flight （without rotor wing）. Engineering empirical equation was used to estimate aerodynamics interference of rotor wings on fuselage. The final results show that the design scheme of helicop- ter has a low RCS level, the aerodynamic drag of the fuselage is decreased effectively while the interference of rotor wings on fuselage is enhanced. -RCS can be reduced by the appropriate selec- tion of the tilt angle of fuselage and vertical tail, and only a relative small price should be paid for aerodynamics performance.