氧化剂温度对固液火箭发动机性能影响仿真研究

Simulation Study on Effects of Oxidizer Temperature on Performance of Hybrid Rocket Motor

关键词:  固液火箭发动机  燃烧室  氧化剂温度  性能参数  数值仿真

Key words:  Hybrid rocket motor  Combustor  Oxidizer temperature  Performance parameters  Numerical simulation

摘要:

为了扩展固液火箭发动机的应用空间，需要研究不同氧化剂温度下固液火箭发动机的性能参数变化。采用集中参数法，通过分析汽蚀文氏管中氧化剂流动受温度的影响，得到温度变化引起的流量偏差，并建立H₂O₂/PE（聚乙烯）固液火箭发动机动态数值仿真模型，利用动网格技术模拟燃面退移，计算氧化剂流量偏差引起的性能参数变化。根据实际经验，选择最低温度为10℃，最高温度为50℃，引起流量偏差约为5%。结果表明：不同氧化剂温度下燃烧室压强和推力偏差会随着工作时间逐渐增大。在0~4s工作时间内，燃烧室压强差从最初的5.67%达到5.96%，发动机推力差从最初的3.28%达到3.51%；不同氧化剂温度下燃速变化趋势基本相同，燃速偏差在工作过程中基本不变；不同氧化剂温度下燃料流量变化趋势相同，但高温工况存在明显的延迟，并且延迟时间随着工作时间显著增长。

Abstract:

In order to expand the application of hybrid rocket motor， it is necessary to study the performance parameter changes at different oxidizer temperatures. Lumped parameter method is used to analyse the mass flow rate changes in the cavitation venturi tube affected by the different oxidizer temperatures in this project. And a transient numerical simulation model of the H₂O₂/PE hybrid rocket motor is established， using the dynamic mesh technology to simulate the regression of propellant. The performance parameter changes caused by the oxidizer mass flow rate deviation are calculated. According to practical experience， an oxidizer mass flow rate deviation of about 5% is obtained at different oxidizer temperatures. The lowest temperature is 10℃ and the highest temperature is 50℃. The numerical simulations show that the combustion chamber pressure and thrust deviation at different oxidizer temperatures will gradually increase with time. The pressure deviation has increased from the initial 5.67% to 5.96%， and the thrust deviation has increased from the initial 3.28% to 3.51% within 0~4s. Regression rate trend is the same at different oxidizer temperatures， and regression rate deviation is basically constant during the working process. The fuel mass flow rate trend is the same at different oxidizer temperatures. However， there is an obvious delay time at high temperature， and the delay time increases significantly with the working time.