混合火箭发动机燃料退移特性的数值计算

Numerical calculation on behavior of fuel regression in hybrid rocket motor

关键词:  混合火箭发动机  燃料退移  尺度效应  数值仿真

Key words:  Hybrid rocket motor  Fuel regression  Scale effect  Numerical simulation

摘要:

混合火箭发动机在航天推进领域优势明显,但由于氧化剂和燃料相态不同,燃料退移的机理和特性比较复杂。采用自行编写的混合火箭发动机程序(HRM)模拟了这种发动机的非稳态工作过程。通过该程序实时数值求解了从氧化剂注入端到尾喷管的全部物理化学过程,并基于燃料表面上气固间的质量和能量耦合,运用燃料表面动态退移和两步计算方法,模拟了燃料退移。在与发动机推力和燃料退移量等实验数据对比的基础上,给出了燃料退移速率方程和燃料退移速率随燃烧室直径的变化规律,确定并分析了影响混合火箭发动机尺度效应的因素。

Abstract:

Hybrid rocket motor has many advantages for space propulsion applications. The mechanism and behavior of the fuel regression in the motor are complicated due to different phase states of the oxidizer and the fuel. The hybrid rocket motor code (HRM) for the unsteady simulation of motor operation has been programmed. This code can calculate physical and chemical processes from the oxidizer injector to the nozzle during motor operation. The mass and energy coupling between gas and solid phases as well as a dynamic fuel surface regression technique with a two-step calculation method is applied to simulate the fuel regression. The calculated motor thrust and fuel regression are compared to the experimental data for the code validation. The fuel regression rate equation and the relation between fuel regression rate and chamber diameter have been derived. The reasons for scale effect in hybrid rocket motor have been determined and analyzed.