喷管不同摆角对水下发射导弹受力的影响

论文研究了带摆喷管推力矢量控制系统的导弹水下垂直发射时,不同喷管摆角对三维水气流场的非定常发展变化过程及对导弹受力的影响。采用燃气泡物理模型,通过水气流场的耦合计算研究燃气与水的相互作用,运用欧拉-拉格朗日和时间步进的方法跟踪燃气泡自由面。以三维欧拉方程为控制方程对喷管和燃气泡内的三维气流场进行数值计算,根据燃气泡不断运动变化的交界面生成贴体动网格,在贴体坐标系下采用无波动、无自由参数、耗散的差分格式(NND差分格式)数值求解三维气流场。采用势流理论,以拉普拉斯方程为控制方程,利用三维Hess-Smith方法数值求解了导弹与燃气泡周围的三维水流场。给出了不同时刻泡形的变化,气流场内马赫数、压力的演变规律,导弹受力及力矩。通过多个工况的对比计算,研究了喷管摆角对导弹受力及水气流场的影响。

The effects of nozzle deflection angles on a missile launched underwater

The effects of nozzle deflection angles on fluid flows and hydrodynamic loads on a missile launched underwater were numerically studied.After the ignition of an underwater missile,the interaction between the exhausted gas and water flows, gives rise to an exhausted gas bubble.The detailed growing process of a three-dimensional unsteady exhausted gas bubble,as well as its effect on the force and moment acting on the missile with thrust-vectoring control system,were investigated by the coupling algorithm of the water flow and gas flow.For the gas flow,the explicit difference scheme of Non-oscillation and Non-free-parameter Dissipation(NND) was utilized to solve the Euler equations for compressible fluids in the body-fitted coordinates.For the water flow,the Hess-Smith method was employed to solve the Laplace equation for the velocity potential of irrotational water flows based on the potential theory and boundary element method.The hybrid Euler-Lagrange formulation for the free surface boundary conditions were used to trace the free surface of the exhausted gas bubble in time stepping computation.On the free surface of the exhausted gas bubble,the matched conditions of both normal velocities and pressures are satisfied.Numerical results of the movement of the shock wave and the distribution of the Mach number and the gas pressure within the bubble were presented.Influences of various nozzle deflection angles on the gas flow and the performance of the engine,as well as the force exerting on the missile are discussed.