多机并联火箭羽流流场及其底部热环境分析

Analysis of Plume Flow Field and Base Heating Environment of Multi-engine Cluster Rocket

针对某多机并联火箭羽流流场结构复杂、底部热环境极为恶劣,有可能导致发动机结构部件失效的问题,通过数值仿真对其飞行过程不同高度下的羽流流场及热环境进行研究,并与热环境实测结果进行了对比分析。计算结果表明:火箭低空飞行时,各发动机羽流互不干扰,随着飞行高度不断增加,羽流逐渐扩张并开始相互干扰,最后在箭体底部出现明显回流,最大热流在起飞时刻,与飞行实测值基本一致。出现回流之前,箭体底部主要受辐射热影响,随着回流出现,对流热流随之增大,但也远小于起飞时刻的热流峰值。计算得到的多机并联火箭羽流流场及其热环境分布对发动机舱外结构热防护优化设计具有一定的指导意义。

For the problem that the plume flow field structure of a multi-engine parallel rocket is complicated and the bottom thermal environment is extremely harsh,which may cause the failure of the engine structural components,the plume flow field and thermal environment at different altitudes are studied through numerical simulation.The result is compared with the measured results in flight which shows that when the rocket is flying at a low altitude,the plume of the engines do not interfere with each other.As the flight altitude increases,the plumes gradually expand and begin to interfere with each other,and finally there is an obvious backflow at the bottom of the rocket.The maximum heat flux at the moment of takeoff is basically the same as the measured value in flight.Before the backflow occurs,the heat flux mainly consists of radiant heat,the convective heat flow increases as the flight altitude grows,but it is also much smaller than the peak heat flow at takeoff.The result has certain guiding significance for the optimal design of engine structure thermal protection.