空气深度预冷组合循环发动机吸气式模态建模及性能分析

针对空气深度预冷组合循环发动机——协同吸气式火箭发动机(Synergistic Air-Breathing Rocket Engine,SABRE),采用部件法对其进行建模,匹配计算得到吸气式模态下飞行走廊内其性能参数变化规律,并研究其高度速度特性。计算模型可信度较高,推力误差小于6%,能够较为准确地模拟SABRE吸气式模态的性能参数。结果表明:SABRE兼具火箭发动机大推力和航空发动机高比冲的特点,吸气式模态下比冲介于21 300~27 380 m/s,随着高度速度的增大,其推力比冲先增大后减小;SABRE利用预冷器将入口空气温度降低,可使其空域速域拓宽至25 km、5Ma,满足高超声速飞行的动力需求;发动机速度下限由压气机最大流量决定,速度上限则由氦气回路减压器工作限制条件决定。

Modeling and performance analysis of deeply precooled combined cycle engine in the air-breathing mode

The paper carries out modeling and performance calculation for the deeply precooled combined cycle engine. The selected engine is Synergistic Air-Breathing Rocket Engine(SABRE). A steady component-level model of the engine was constructed. The rule of performance variation of engine in the air-breathing mode along the flight trajectory was obtained, and the height and velocity characteristic of engine was studied. The model is reliable with thrust error less than 6%, and it can be used to calculate performance of SABRE under the air-breathing mode. It is indicated that SABRE is characterized by both large thrust as rocket engines and high specific impulse as aircraft engines, and its specific impulse is between 21300~27380m/s; along with the increase of altitude and velocity, the thrust and specific impulse of SABRE increase first and then decrease. By decreasing the inlet airstream temperature with precooler, the range of height and velocity of SABRE was enlarged to 25km and Mach 5, which is needed by hypersonic flight; the lower limitation of velocity was decided by the maximum mass flow rate of compressor, and the higher limitation was decided by the operation rule of helium loop.