点火延迟对单组元自激式脉冲推力器的性能影响

Analysis of the Ignition Delay Effects on Monopropellant Self-Excited Pulse Thruster

关键词:  液体火箭发动机  脉冲推力器  点火延迟  自激  单组元推进剂 

Key words:  Liquid propellant rocket engine  Pulse thruster  Ignition delay  Self-excitation  Monopropellant

摘要:

点火延迟是脉冲推力器设计中需要考虑的重要因素之一。为研究点火延迟对自激式脉冲推力器的性能影响,以HAN基(Hydroxylammonium Nitrate)单组元推进剂为例,建立自激式脉冲推力器工作过程的仿真模型,分析了点火延迟时间的变化对推力器的压强、流量、推力及平均比冲的影响规律。结果表明,点火延迟会强化脉冲推力器的压强爬升过程,随着点火延迟时间的增大,一个脉冲循环中的推进剂燃烧持续时间和整个脉冲周期均会明显缩短,同时挤压腔压强峰值和燃烧室压强峰值以及推力器的平均推力水平也会显著升高,但点火延迟的变化基本不会影响脉冲周期内的平均比冲。点火延迟提供了一条调节脉冲工作特性的可能途径,研究点火延迟特性对自激式脉冲推力器的探索与应用具有重要的指导意义。 

Abstract:

The ignition delay is an important factor which needs to be considered carefully in the pulse thruster design. To investigate the effects of ignition delay on the self-excited pulse thruster, a mathematical model was set up to describe the pulsating process adopting HAN (Hydroxylammonium Nitrate)-based monopropellant. The impact on the pressure, mass flow, thrust and specific impulse of the thruster was analyzed when the ignition delay was changed. For the self-excited thruster, the ignition delay strengthens the extrusion, injection and combustion process. With the delay increasing, the duration of the combustion in a cycle and the whole cycle period become much shorter,and the magnitude of the pressure peak both in the extrusion room and in the combustion chamber ascend obviously at the same time. Few influence of the delay on the average specific impulse in a cycle period is observed though the longer delay would result in the higher average thrust. The ignition delay may be a possible approach to adjust the pulsating characteristics of the self-excited pulse thruster.Thus,the relative study is important to explore and apply this novel rocket engine. 