带二次流增推喷管的脉冲爆震发动机推进性能分析

Propulsive Performance of Pulse Detonation Engine with Fluidically Augmented Nozzle

关键词:  广义一维流动模型  等容循环模型  脉冲爆震发动机  二次流喷管  落压比  推力系数

Key words:  Generalized 1D flow model  Constant volume cycle model  Pulse detonation engine  Fluidic nozzle  Nozzle pressure ratio  Thrust coefficient

摘要:

为了研究带二次流喷管的脉冲爆震发动机的推进性能，结合广义一维流动模型和等容循环模型建立了对应的数学模型，对在二次流影响下的喷管推力系数进行了研究。计算结果表明:在定常流动中，若喷管几何构型不变，当喷管落压比小于一个临界值时，注入二次流可以提高其性能。在爆震循环中，若燃烧后压力一定，存在一个最佳扩张比的喷管，使发动机平均推力系数达到最大值，若二次流连续注入，当喷管的扩张比大于一个临界值时，注入二次流会提高发动机性能，但是不能提高其最大平均推力系数；采用间断注入二次流的方案，可以提高此燃烧后压力对应的最大平均推力系数，当燃烧后压力为5MPa时，提升率可以达到2.4%。

Abstract:

Both generalized 1-D flow model and constant volume cycle model are employed to investigate the performance of pulse detonation engine with a fluidic nozzle. Thrust coefficient of a fluidic nozzle in steady flow and average thrust coefficient of a pulse detonation engine with a fluidic nozzle during a pulse detonation cycle have been calculated. In the steady flow，fluidic nozzle shows a better performance than its baseline nozzle when nozzle pressure ratio is lower than a critical value. During a pulse detonation cycle，for a certain initial uniform combustion pressure，the fluidic nozzle with a continual second injection can augment the average thrust coefficient when the expansion ratio is higher than a critical value. Interrupted injection can improve the max average thrust coefficient for this initial uniform combustion pressure by 2.4% when initial uniform combustion pressure is 5MPa.