硝酸羟胺基单组元液体火箭发动机起动过程的模拟

Simulation of Start-Up Transient Process for Hydroxylamine Nitrate-Based Liquid Monopropellant Rocket Engine

关键词:  硝酸羟胺  单组元液体火箭发动机  起动  数值模拟  相变

Key words:  Hydroxylamine nitrate  Liquid-monopropellant rocket engine  Start-up  Numerical simulation  Phase change

摘要:

无毒单组元液体火箭发动机是空间推进的发展方向之一。针对硝酸羟胺基单组元液体火箭发动机的起动过程，建立了零维模型、不考虑相变过程的仿真模型和考虑相变过程的仿真模型，并采用这些模型对60 N发动机进行了起动过程的模拟和对比分析。计算结果显示，推力室升压过程历经快速的气体充填和较慢的催化室升温两个阶段。零维计算模型和不考虑相变的CFD方法计算得到的两个阶段时长基本一致，但第一阶段时间显著低于试验结果，第二阶段时长与试验结果符合。考虑推进剂相变过程的模型计算结果与试验结果符合较好。一维计算得到HAN基推进剂在进入催化床约4mm的长度内完全分解。升压第一阶段受催化分解影响很大,HAN基推进剂的分解反应速率低于肼的分解反应速率。

Abstract:

Non-toxic monopropellant engine is one of the key research direction of space propulsion. Aiming at the starting process of hydroxylamine nitrate (HAN) monopropellant rocket engine, the zero-dimensional model, simulation models with and without phase change process were established and applied to simulate the starting process of a 60N rocket engine. The calculation results show that the starting process of the chamber pressure goes through two stages, which corresponding to a fast process of the gas filling and a slow process of the temperature rise of the catalyst bed， respectively. The results calculated by the zero-dimensional model and the CFD method without phase change are nearly identical. The duration of the first stage is significantly shorter than that of the test, and that of the second stage agrees well with the test. The results calculated by the model with the phase change of the liquid propellant agree well with the test. One-dimensional calculation shows that the HAN-based monopropellant decomposes completely within the length of about 4 mm entering the catalytic bed. Catalytic reaction has an great influence on the first stage of pressurization, and the rate of decomposition of HAN-based monopropellant is much lower than that of hydrazine.