火箭级间冷分离过程后期阶段的耦合数值模拟

Coupled numerical simulation for the later period of the stage separation of a multi-stage rocket

关键词:  多级火箭  级间分离  Chimera/Overset方法  数值仿真

Key words:  Multi-stage rocket  Stage separation  Chimera/overset method  Numerical simulation

摘要:

多级火箭二三级级间冷分离过程后期阶段的飞行遥测数据表明,在三级火箭后封头中部存在约50kW/m2的热流峰值。由于遥测数据有限,为了弄清燃气在级间流动的机理和热流产生的原因及影响,采用Chi-mera/Overset方法并结合N-S方程和刚体动力学方程,以流动和刚体动力学耦合计算的方式对多级火箭二三级级间冷分离过程的后期阶段进行了数值模拟,研究了轴对称和三级喷管有偏转两个工况的分离特性。结果表明,轴对称工况分离过程的流场存在剧烈的振荡,而三级喷管有偏转工况分离过程的流动比较平稳,对这两种流动的成因进行了分析,并讨论了这两个工况下三级后封头附近的热环境的区别。计算结果可为级间分离段的设计提供参考。

Abstract:

Telemetry data of flight showed that there was a heat flux peak value of 50kW/m2 on the midpoint of aft-dome of upper-stage during the later period of the stage separation of a multi-stage rocket. In order to investigate the flow mechanism of the stage separation and the cause and effect of the heat flux,coupled CFD and rigid body dynamics simulation by means of chimera/overset method is performed to study the dynamic and aerodynamic characteristics of the later period of the stage separation of a multi-stage rocket. Both an axisymmetric case without the third stage nozzle rotation and a three-dimensional case with the third stage nozzle rotation have been studied. The results show that flow field of the axisymmetric case shows significant oscillation while stage separation of the three-dimensional case is relatively smooth. The reason for this difference is investigated. The difference of thermal effect on the aft-dome of the upper-stage between the two cases has also been studied.