固体火箭冲压发动机固定几何喷管设计问题(英文)  

Design problems of fixed-geometry nozzle of ducted rocket

作　　者：徐东来[1] 陈凤明[1] 蔡飞超[1] 杨茂[1] 

机构地区：[1]西北工业大学航天学院,西安710072

出　　处：《固体火箭技术》2010年第1期45-48,共4页Journal of Solid Rocket Technology

摘　　要：针对现有弹用固体火箭冲压发动机普遍采用的固定几何不可调节喷管，基于流量平衡的基本原理，建立了其理论设计及性能评估的数学模型。结合当前中远程空空导弹提出的Ma=2～3．5宽速度范围设计需求，运用所建立设计模型对实例设计方案开展了计算分析。结果表明，现有固定几何喷管本质上是为满足低速正常接力而折中设计出的，在高速巡航时，因扩张比偏小，不仅喷管出口气流速度和冲量小，而且导致燃烧室压强降低，还额外造成进气道结尾正激波总压损失加大，不能将进气道保有的捕获高速来流动能充分发挥出来。原设计方案在Ma=3．5高速巡航时，进气道实际总压恢复性能对比方案中的最大总压恢复性能水平，相对损失幅度高达42．67％，而且冲压发动机推力与其可能达到的最大值对比，相对损失幅度也高达31．8％。因此建议采用喷管调节技术来解决此类问题。Aiming at fixed-geometry nozzle popularly used for existing ducted rockets, a mathematical model for analytical de- sign and performance evaluation of nozzle is established based on the principle of mass flow balance. To meet the design require- ments of Mach number 2 to 3.5 range for modern medium-to-long range air-to-air missile applications, nozzle design and analysis u- sing present model is carried out. The results show that existing fixed-geometry design is essentially a compromise to satisfy low- speed takeover requirements. During high speed cruise process, lower nozzle expansion ratio causes not only lower exit flow velocity and impulse, but also lower pressure in combustion chamber. In addition, lower nozzle expansion ratio also results in higher total pressure loss of exit terminal normal shock wave. Therefore, free stream kinetic energy captured by the inlet can not be fully uti- lized. During Ma = 3.5 cruise process, actual total pressure recovery performance in original design has a relative loss of 42.67% compared to maximum potential value, and relative thrust loss of 31.8% compared to maximum achievable value of ducted rockets. Therefore, it is advised that nozzle regulation technology should be used to solve this problem.

关 键 词：固体火箭冲压发动机 喷管 扩张比 推力 总压恢复系数 

分 类 号：V438[航空宇航科学与技术—航空宇航推进理论与工程]