超音速伞弹流场特性数值分析

Numerical Analysis of Flow Field Characteristics of Supersonic Submunition with Parachute

伞弹系统超音速流场特性直接关系到伞弹在超音速条件下的气动力性能,对流场特性进行分析和研究能够为伞弹设计和使用提供参考依据。通过建立分块结构化计算网格,基于有限体积法和SST湍流模型对飘带伞和平头子弹组成的伞弹系统进行超音速数值模拟,采用数值纹影法显示流场分布。结果表明,伞弹超音速流场结构复杂,包含多种激波形态和流态。通过研究得到:伞弹流场相互耦合,伞使得弹体尾流驻点距离减小;伞弹流场类型可分为开式流动和闭式流动两类,临界点为喉部位置,流场类型对伞的阻力系数影响很大;随着马赫数的增加,弹体头部激波脱体距离以及弹体和伞的尾流驻点距离都不断减小,变化幅度也减小。

The flow field of the supersonic submunition with parachute has a big influence on its aerodynamic performance.The analysis of its characteristics and law of variation can provide reference basis for its design and usage.CFD simulations of flat-faced submunition with disk-streamer parachute were carried out based on multi-block structured grids.Finite volume method and SST turbulence model were used in the simulation.The flow fields were displayed by numerical schlieren method.The results show that the flow field of the submunition with parachute is complicated and has several shock-wave and flow patterns.It is concluded that the flow field of the parachute influences counterpart of submunition and decreases its wake stagnation distance.The type of flow field can be divided into open type and closed type by the neck station of the submunition wake,and has a big influence on the drag coefficient of the parachute.As the Mach number increases,both the detached distance of the submunition＇s head shock and wake stagnation distances of the parachute and submunition decrease,as well as the decline amplitudes.