某带减速气囊的航空子弹气动特性研究

Research on Aerodynamic Characteristics of a Bullet with Deceleration Airbag

为研究某带减速气囊的亚音速航空子弹大攻角飞行的气动特性,验证充气式减速气囊的减速效果,采用数值计算方法对该模型的流场进行仿真。建立了带减速气囊的子弹几何模型,划分了结构化网格、设置仿真参数进行了定常计算。得到了模型在马赫数分别为0.4、0.6、0.8,攻角为0°~90°工况下的升力系数、阻力系数、俯仰力矩系数,对其气动特性进行了分析和弹道仿真。结果表明:阻力系数在攻角为0°~10°、30°~60°时与其正相关,在10°~30°、60°~90°与其负相关;升力系数在攻角大于50°时急剧下降且在大于55°变为负值;负向俯仰力矩在攻角为0°~50°逐渐增大,50°~90°变化幅度较小。对于亚音速航空子弹大攻角飞行,3 s内速度能从300 m/s减速至83 m/s内,并且采用充气式减速气囊可以很好地稳定姿态。

In order to study the aerodynamic characteristics of a subsonic aviation bullet with a deceleration airbag flying at a large angle of attack,and verify the deceleration effect of the inflatable deceleration airbag,the flow field of the model was simulated by a numerical calculation method.We established a geometric model of the bullet,and the computational domain was divided into structured grids.The lift coefficient,drag coefficient and pitching moment coefficient of the model under the conditions of Mach number of 0.4,0.6,0.8 and angle of attack of 0°~90°were obtained,and its aerodynamic characteristics were analyzed and ballistic simulation was carried out.The results show that the drag coefficient is positively correlated with the angle of attack of 0°~10°,30°~60°,and negatively correlated with it at 10°~30°,60°~90°.The lift coefficient drops sharply when the angle of attack is greater than 50°and becomes negative when it is greater than 55°.The negative pitching moment gradually increases as the angle of attack increases from 0°to 50°,and varies very small in the range of 50°~90°.For subsonic aviation bullets flying at a large angle of attack,the speed can be decelerated from 300 m/s to 83 m/s within 3 s,and the inflatable deceleration airbag can be used to stabilize the attitude.