Research and Development of Supersonic Combustion Strut with a Preburner

超声速推进装置的成功发展需要点火和火焰稳定的知识。由于这种装置内的流动是超音速的，与亚音速燃烧器内的情况相比，混合和反应时间大大减少。显著减少混合和反应时间的一个直接含义是，在延长点火延迟和更大的火焰熄灭或吹灭倾向方面，增强了火焰稳定过程的敏感性。本研究首先是利用预燃方法解决低马赫数超声速气流的点火和稳焰问题。其次，研究超声速气流中预燃氢的燃烧机理和火焰结构。第三，了解预燃氢在超音速气流中的燃烧稳定性。第四，建立了超声速湍流燃烧的数值计算方法。对超声速气流中预燃氢的燃烧进行了数值和实验研究。这些研究主要涉及点火、火焰稳定、火焰结构和燃烧机理以及反应流的数值计算方法。首先，对预燃法引燃和保火的可能性进行了预测。结果表明，采用预燃方法可大大降低自燃温度极限。此外，还研究了预燃器等效比、预燃器压力和超声速气流温度对火焰发展的影响。认识到这三个参数中的每一个都对火焰保持和燃烧发展有重要影响。通过数值模拟和实验对预燃氢的火焰稳定性极限进行了预测。

For the successful development of supersonic propulsion devices the knowledge of ignition and flame stabilization is needed. Since flows within such devices are supersonic, the mixing and reaction times are drastically reduced as compared to the situation within subsonic combustors. A direct implication of the significantly reduced mixing and reaction times is the enhanced sensitivity of the flame stabilization processes in terms of extended ignition delays and the greater propensity of the bulk flame to be extinguished or blown out.This study intends to first, solve the problem of ignition and flame stabilization in low Mach number supersonic airflow by using preburning method. Second, to investigate the combustion mechanism and flame structure of preburned hydrogen in supersonic airflow. Third, to understand the flame stability regime of preburned hydrogen in supersonic airflow. Fourth, to develop a numerical method for computation of supersonic turbulent combustion.Numerical and experimental studies on combustion of preburned hydrogen in supersonic airflow were done. These studies mainly were concerned with ignition, flame stabilization, flame structure and combustion mechanism as well as numerical method for reactive flows. First, the possibility of ignition and flame-holding by preburning method was predicted. It was shown that the temperature limit of auto-ignition is drastically reduced by using the preburning method. In addition, the effect of the preburner equivalence ratio the pressure of the preburner and the supersonic airflow temperature on flame development were studied. It was realized that each of these three parameters had significant effects on flame-holding and combustion development. Futhermore, flame stability limits of preburned hydrogen were predicted by numerical simulation as well as experiment.