部分裂解煤油的旋转爆震发动机数值模拟

(西安航天动力研究所液体火箭发动机技术重点实验室,陕西 西安 710100)

旋转爆震发动机; 预先加热; 爆震燃烧; 煤油裂解; 发动机性能评估

Numerical simulation of partially cracked kerosene rotating detonation engine
WANG Dan,ZHOU Chenchu,CHEN Hongyu,YAN Yu,HONG Liu

(Science and Technology on Liquid Propulsion Rocket Engine Laboratory,Xi'an Aerospace Propulsion Institute,Xi'an 710100,China)

rotating detonation engine; pre-heating; detonation combustion; kerosene crack; engine performance evaluation

备注

采用液态煤油作为燃料的旋转爆震发动机具有结构简单、性能高、推进剂可长期贮存的优势,但存在煤油起爆困难的问题。以煤油—空气作为推进剂的旋转爆震发动机为研究对象,研究通过预先加热使得煤油部分裂解再进行点火的起爆过程。建立部分裂解煤油化学反应模型,开展燃烧室内的点火起爆过程仿真分析,计算结果表明,在点火起爆的初始阶段爆震波的形成和发展具有一定的不确定性,进入燃烧室的燃料组分对形成稳定爆震波所需的时间及爆震波最终的传播方向均有影响。裂解率的提升可能导致燃烧区发生缓燃,使得形成稳定爆震波的时间延后。发动机稳定工作时,不同裂解率条件下旋转爆震波传播频率均为7 500 Hz,爆震波峰值压力2.3 MPa,发动机比冲在不同周期略有起伏,平均比冲均维持在1 340 m/s。

The rotary detonation engine using liquid kerosene as fuel has the advantages of simple structure, high performance and long-term storage of propellant, but it is difficult to initiate kerosene detonation. Taking the rotating detonation engine with kerosene-air as research object, the ignition process of a rotating detonation engine under pre-heating mode which leads to kerosene cracking was putted out. The chemical reaction model of partial cracking kerosene was putted out and the ignition process in the combustion chamber was simulated. The results show that the formation and development of detonation wave in the initial stage of ignition have uncertainty. The fuel components entering the combustion chamber have effect on the time required for building a stable detonation wave and the final propagation direction of the detonation wave. Increasing cracking rate of kerosene may result in slow combustion in the zone which will delay the formation of stable detonation waves. The frequency of the rotational detonation wave propagation is almost 7 500 Hz and peak pressure of detonation wave is almost 2.3 MPa under the condition of different cracking rates during the engine steady operation time. The specific impulse of engine varies slightly during different period and the average specific impulse is almost 1 340 m/s under the condition of different cracking rates.