Abstract: To take more research about plume impact characteristics of multi-nozzle rocket propulsion system，the launch platform consisted with multi-nozzle rocket propulsion system is taken as the research object. The three-dimensional N-S equations are used to describe the impact flow process. The Realizable k-ε model is coupled with the flow equations，and the PISO algorithm is used to solve the N-S equations. The parameters of impact flow-field on different deflecting-plane are acquired. The simulation results indicate that the most serious impact regions are along the axis of engines on the deflecting plane，the boosters’ impingement is much stronger than the core vehicle. The cone-plane is of better deflecting function for the multi-nozzle propulsion system plume，and can do a better job to reduce the impact effect of plume than the wedge-plane. However，reversed flow is formed on the cone-plane and it may bring the hot exhaust and heat up the air around the launch platform which may destroy the system. So relevant protective measures are necessary to be taken.

Key words: Multi-nozzle；Liquid rocket engine；Plume；Flame-deflector；Impact

摘要： 为深入研究多喷管液体火箭动力系统尾焰冲击特性，以由多喷管液体火箭动力系统构成的发射平台为研究对象，采用三维N-S方程描述尾焰冲击流动过程，采用Realizable k-ε湍流模型封闭流动方程组，并运用压力的隐式算子分割(PISO)算法进行求解，得到了火箭动力系统尾焰对不同导流面导流槽的冲击流场参数。结果表明:导流面上受冲击影响最大的是沿喷管轴线方向的正冲击区域，且助推器尾焰对导流面的冲击效应相比于芯级更加强烈。锥形导流面对多喷管动力系统尾焰具有很好的引射和导流作用，相比于楔形导流面更能降低尾焰的冲击影响，但会在流场中形成漩涡并卷吸高温燃气，可能对发射系统造成破坏，需要增加相应的热防护措施。

关键词: 多喷管；液体火箭发动机；尾焰；导流槽；冲击