固体火箭发动机后效推力对导弹底阻影响的数值仿真

Numerical simulation of influences of solid rocket motor post-thrust on missile base drag

采用二维轴对称N-S方程与湍流模型相结合,建立了固体火箭发动机喷管尾流和弹体外流一体化仿真模型.针对给定的导弹模型,开展了不同发动机燃气流量下的流场仿真,得到了流场速度和压力分布,分析了不同燃气流量下发动机后效推力对导弹底阻的影响.结果表明:与发动机不工作时相比,加入较小的燃气流量后,导弹底部压力增大,底阻值减小.随着燃气流量的增加,底部压力先减小后增大,底阻先增大后减小.随着燃气流量的增加,后效推力与导弹底阻的合力不断增大,且动推力所占比重逐渐增加.

Coupled with two-dimensional axisymmetric N-S equation and turbulence model,integral flow field simulation models were established for solid rocket motor nozzle tail flow and missile outer flow.For a given missile model,numerical simulations were carried out under different combustion gas mass flow rates.Velocity and pressure contours were obtained and influences of solid rocket motor post-thrust on missile base drag were analyzed under different combustion gas mass flow rates.According to the results,compared with the case when the motor was in idle condition,the missile base pressure increased and base drag decreased under low combustion gas mass flow rate.As the combustion gas mass flow rate increased,the missile base pressure decreased first and then increased;on the contrary,the missile base drag increased first and then decreased.As the combustion gas mass flow rate increased,resultant force of post-thrust and base drag increased,and the proportion of momentum thrust increased gradually.