Abstract: In order to take more research about plume flow-field characteristics of multi-nozzle rocket propulsion system consisted of ten liquid rocket engines，the N-S equations coupled with Realizable k-ε model are used to describe the flow process. The PISO algorithm is used to solve the N-S equations and the effect of afterburning is considered in the simulation. The coupling simulation of [LH2]/LOX engine and LOX/kerosene engine exhaust plume is accomplished. The plume flow-field structure and parameter distribution of rocket exhaust plume at different altitude are acquired. The simulation results indicate that with increasing the flight altitude，the expansion angle of plume increases and the interaction between plumes is enhanced. Because of the effect of afterburning and interaction between plumes，partial high temperature regions will occur in the flow-field. Besides，reversed flow is formed around the after-body of the rocket and nozzles. The reversed flow can bring the hot exhaust and heat up the air around the after-body. So the thermal protection should be taken at these places.

Key words: Liquid rocket engine；Multi-nozzle；Afterburning；Plume；Numerical simulation

摘要： 为深入研究多喷管液体火箭动力系统尾焰流场特性，以由10台液体火箭发动机组成的多喷管动力系统为模型，采用耦合了Realizable k-ε湍流模型的N-S方程描述尾焰流动过程，考虑复燃反应的影响，并运用压力的隐式算子分割(PISO)算法进行求解，实现了以液氢液氧和液氧煤油为推进剂的两种不同发动机尾焰的混合计算，得到了不同飞行高度下火箭动力系统的尾焰流场结构及其参数分布情况。结果表明:随着飞行高度的升高，尾焰的膨胀角度越来越大，尾焰间的相互作用加强。由于复燃反应及尾焰间相互作用影响，尾焰流场会出现局部高温区域，同时火箭底部及喷管周围会出现旋流，旋流会卷吸尾焰高温燃气，从而会对火箭底部进行烧蚀，需要对其采取相应的热防护措施。

关键词: 液体火箭发动机；多喷管；复燃反应；尾焰；数值仿真