稠密大气层内火箭头罩动态分离过程数值模拟

Numerical Simulation of the Detaching Process for Rocket Mantles in Low Altitude

利用弹簧近似和网格局部重构相结合的非结构动网格技术,耦合求解Euler方程及6DOF弹道方程,时间方向采用四步Runge-Kutta方法,空间方向采用改进的Barth和Jespersen通量限制器的通量矢量分裂方法,数值模拟稠密大气层内、超声速飞行状态下、内部有冲压发动机的火箭头罩分离动力学过程.研究结果表明,头罩开启过程中,高动压会产生严重的气动力扰动;头罩脱离火箭进入自由飞行状态以后,分离过程中气动力比惯性力大几个数量级,导致头罩的运动特性完全由气动力控制,姿态变化剧烈,分离存在很大风险;采用质心后移分离方案可行.

Using dynamic unstructured grid technology combined by spring analogy and local remeshing, the Euler equation coupled with 6DOF trajectory equations was solved. Solutions were advanced in time by a four-stage Runge-Kutta time-stepping scheme. The flow solver was an improved implementation of Barth and Jespersen＇s unstructured schemes. The mantles detaching process of rocket with rocket-based combined-cycle （RBCC） inside was simulated numerically under the conditions of supersonic aviation in low altitude. The results show that high dynamic pressure can cause aerodynamic disturbance in course of mantles unbolting and releasing. After mantles breaking away, the aerodynamic force is several orders of magnitude greater than the inertia force. Mantles trajectory is absolutely controlled by the aerodynamic force and the mantle statement changes violently. This may cause great risk. The detaching project of the mantle＇s centroid moving backwards is feasible.