采用三维雷诺平均N-S方程和k-ε湍流模型对固体火箭发动机燃气二次喷射矢量喷管内外流场进行数值模拟,研究飞行参数对矢量喷管内主/次流耦合流场的影响。结果表明,自由来流造成喷管出口附近压力变化,通过喷管内壁面附面层作用影响喷管内部流动特性。飞行马赫数为超声速,或者环境压强较低时,侧向力大小与飞行参数无关。在低空亚声速流中,侧向力随飞行马赫数增加迅速减小,随环境压强降低而减小。 The three-dimensional Reynolds averaged N-S equation and k-ε turbulence model were used to simulate the internal and external flow field of the solid secondary rocket motor gas injection vector nozzle. The influence of flight parameters on the main / secondary flow field in the vector nozzle was studied. The results show that the free flow causes the pressure near the exit of the nozzle to change, and the flow characteristics inside the nozzle are affected by the inner surface of the nozzle. When the flight Mach number is supersonic or the ambient pressure is low, the magnitude of the lateral force is independent of the flight parameters. In low subsonic flow, the lateral force decreases rapidly with the increase of flight Mach number, decreases with the decrease of ambient pressure.