流体喷管的脉冲爆震发动机出口过膨胀优化数值研究

在脉冲爆震发动机工作过程中,爆震室压力处于强非定常状态.传统的型面不可调尾喷管与可调尾喷管都无法满足爆震室内压力的高频剧烈变化,进而导致较大的推力损失.为了提升现有脉冲爆震发动机型面不可调增推喷管性能,可以从爆震室中引出爆震燃气,通过无阀自适应控制将该二次流喷射在喷管扩张段,实时调节主流的有效扩张面积比,进而形成流体喷...

Numerical study on overexpansion optimization of pulse detonation engine with fluidic nozzle

During the operation of the pulse detonation engine,the pressure of the detonation chamber is in a strong unsteady state.The traditional non-adjustable exhaust nozzle and adjustable exhaust nozzle cannot meet the high-frequency and drastic changes of the pressure inthe detonation chamber,which leads to greater thrust loss.In order to improve the performance of the current fixed-geometry nozzle for the pulse detonation engine,the detonation products extracted from the detonation chamber and named as secondary flow,can be injected into the divergent section of the nozzle by the valveless adaptive control.This is the fluidic nozzle whose effective divergent area ratio can be constantly changed by the secondary flow.Aimed to this type of fluidic nozzle,the flow field in the nozzle and the single-cycle pulse detonation engine influenced by the different injection conditions(such as injection area ratio,position ratio)of the secondary flow were investigated under 2-D numerical simulation while the initial pressure was 1atm,equivalence ratio was 1.0 and the amount of the explosive mixture was fixed.It can be found that the injection of the secondary flow can change the effective flow area of the nozzle,and the larger the injection area ratio of the secondary flow in the divergentsection of the nozzle,the higher the impulse rate of the nozzle is(the maximum increase rate is 5.25%relative to the reference nozzle).Also,the closer the injection position is located to the nozzle throat,the higher the impulse increase rate of the nozzle is.