乙烯燃料超燃冲压发动机流场振荡及其控制研究

Study on Flow Oscillation and Its Control Methods in an Ethylene-Fueled Scramjet Combustor

关键词:  超燃冲压发动机  非定常数值模拟  振荡  频率  性能

Key words:  Scramjet  Unsteady simulation  Oscillation  Frequency  Performance

摘要:

为了研究超燃冲压发动机燃烧室内的流场振荡原因与抑制振荡的方法，采用非定常数值模拟研究了乙烯燃料超燃冲压发动机的流场振荡现象。结果表明:在燃烧室入口马赫数2，静温530K，静压0.1MPa的入流条件下，冷流流场存在振荡现象，主要是由于凹槽内低速流体与主流高速流体形成的剪切层周期性的振荡，流场振荡周期为13.6ms，振荡频率为73.5Hz；K1或K2油位注油当量比0.1，均可以有效地抑制流场的振荡，流场达到稳定所需时间分别为8ms和30ms；K3油位注油当量比0.1或0.2均不能抑制流场的振荡，但使振荡周期由15.13ms转为5.7ms，振荡频率由66.1Hz转变为175.3Hz；五点注油有效地提高了发动机的推力性能。

Abstract:

In order to study the flow oscillation and its control methods，unsteady numerical simulation was used to investigate the oscillation in an ethylene-fueled scramjet combustor. Results show that under the inflow air condition Mach number 2.0，static temperature 530K，static pressure 0.1MPa，the cold flow field is oscillatory for the shear layer produced by the small velocity field in the cavity and the large velocity field in the main flow is periodic oscillatory at the cycle time 13.6ms and the frequency 73.5Hz. The field-oscillation can be controlled by fueled on K1 or K2 location with the equivalence ratio 0.1，the time for the field gets steady is 8ms or 30ms. The field-oscillation can not be controlled by fueled on K3 location with the equivalence ratio 0.1 or 0.2，but the flow cycle time changes from 15.13ms to 5.7ms，the frequency changes from 66.1Hz to 175.3Hz. Fueled on five locations can improve the thrust performance of the scramjet.