带冷罩的自旋弹头在液氮消耗时的姿态模型

Attitude model of spinning warhead with cooled shroud when liquid nitrogen is consuming

研究了带液氮冷屏蔽罩(冷罩)的自旋弹头在自由飞行段中,冷罩多孔介质层内液氮不断消耗时弹头姿态的变化规律.针对工程上无法利用数值计算直接研究多孔介质中液氮消耗对弹头姿态运动影响的问题,以均相模型分析多孔介质层内气液混合物的运动规律,建立了均相介质在离心力作用下的渗流运动方程.对此方程进行无量纲化,分析了均相介质的运动规律,得到了变质量弹头的姿态动力学模型.通过分析与仿真发现,自旋角速度随冷罩内液氮消耗而不断增大,非自旋方向角速度不为零时,其运动频率不断增大,且会产生运动阻尼,但频率变化很小,运动阻尼量级也极小,工程中可忽略冷罩中液氮消耗对非自旋方向的影响.

An attitude dynamics model of spinning warhead flying at free stage with a cooled shroud was established while liquid nitrogen filled in porous medium layer was consuming. The effect of liquid nitrogen movement to spinning warhead is difficult to calculate and simulate directly in engineering, according to this, an infiltration movement model of mixture in porous medium was gained by using homogeneous assumption, then was analyzed by applying dimensionless method, and an applied attitude model was obtained. Simulation shows that angular velocity is increasing in spinning direction, but in other directions, frequencies of angular velocities are increasing while these velocities are not zero, meanwhile, damp effects are appeared in the angu- lar movement. Because of little impaction to attitude angular , both frequencies increase and damp effects couldbe ignored in practical project.