侧置火箭对发动机尾喷管的影响研究

Impact of sidewall rocket on engine nozzle

某些应用条件下,飞行器需要RBCC发动机提供更大的推力,受飞行器/发动机一体化气动外形约束,冲压流道推力很难大幅提高,不得不提高火箭发动机推力。当火箭推力需求过大时,传统的在隔离段或燃烧室流道内布置火箭发动机的方法受限于狭小的空间约束,火箭发动机设计难度增加,性能降低。为此,提出了一种将火箭发动机布置于冲压发动机尾喷管侧壁的方法,并开展了火箭状态对尾喷管性能影响的初步研究。结果表明:这种布置方式充分利用尾喷管较大的几何空间,火箭射流可在尾喷管内继续膨胀,不仅不会削弱尾喷管的推力性能,甚至可以产生额外的推力增量,且其升力会大幅增加。此外,该方式还可实现火箭发动机大推力和高比冲的较好匹配,其应用也可拓展至RBCC发动机外的相似领域。

Sometimes spacecraft need RBCC(rocket based combined cycle) engine to provide greater thrust. For the restriction of the aircraft/engine integrative aerodynamic shape, it is difficult to increase ramjet thrust by a large margin, so the rocket thrust has to be increased. When much more thrust is need, if the rocket engine is packaged within the isolation section or combustor flow passage,the rocket engine design will be more difficult because of the narrow geometric space, and the rocket performance will be reduced. Therefore, a method to place the rocket engine on the sidewall of ramjet engine nozzle is proposed. The influence of rocket status on nozzle performance is study in this paper.The result shows that this arrangement make full use of the nozzle geometric space, the rocket jet flow can continue to expand in the nozzle, by which not only the nozzle thrust will not be weaken, but also the nozzle can attain added thrust increment and its uplift power can be greatly increased. The nozzle sidewall arrangement mode can realize a excellent matching of high thrust and high specific impulse.Its application can also be used in other domains similar to RBCC engine.