新型液体火箭发动机燃烧不稳定性研究

COMBUSTION INSTABILITY OF NEW-STYLE LIQUID ROCKET ENGINE

应用CFD方法对新型液体火箭发动机燃烧过程进行全尺寸数值模拟。首次有针对性地系统得出了混合比、液氧喷雾初始尺寸分布、缩进区液氧蒸发质量对氢氧火箭发动机燃烧振荡的影响规律,评估了1轮毂3径向喷嘴隔板抑制燃烧振荡的效果,并对氢氧、液氧/甲烷两种火箭发动机的燃烧不稳定性特征进行了对比分析。结果表明:存在某一特定的混合比、喷雾液滴直径、缩进区液氧蒸发质量敏感区间,易导致不稳定燃烧;喷嘴轮毂隔板可很好地抑制燃烧振荡;氢氧、液氧/甲烷燃烧分别以高频和低频压力振荡为主。

The combustion process of one full-scale new-style liquid rocket engine was numerically simulated by using CFD methods. The effect rules of O/F equivalence ratio, the LOX spray initial drop size and the evaporation quality at LOX injector recess area on combustion oscillation of LOX/GH2 engine were studied. The control effect of one-hub-and-three-blade injector baffle on combustion oscillation was investigated. Additionally, the combustion instability characteristic of LOX/GH2 rocket engine was compared with that of LOX/CH4 engine. Results show that there are specifically certain bounds of equivalence ratio, the LOX spray initial diameter, and the evaporation quality which can result in combustion instability more easily. The baffle can control the combustion instability. The high frequency oscillation appears in the LOX/GH2 rocket engine, however, the low frequency oscillation appears in the LOX/CH4 engine.