碳氢燃料流向涡掺混超燃模型燃烧室冷态流场数值研究

对一种超声速燃烧模型燃烧室的冷态流场进行了数值研究。为稳定超燃火焰并提高燃烧速率和效率,取少量的冲压空气进行稳定的亚燃预燃烧,并以之作为超燃室的一个稳定火炬,其高温燃气将吸热型碳氢燃料预先蒸发汽化并部分裂解为短链小分子,最后通过城墙波瓣掺混器形成的流向涡带入超声速主流,以期实现快速高效的超燃燃烧。计算结果表明:首先,城墙波瓣掺混器能够在较小总压损失下得到显著掺混效果;其次,本文从气动结构的角度专门探究了亚/超燃接力阶段较低的隔离段进口马赫数存在热堵塞的可能性,发现较难适宜超燃启动点火。

Numerical study of the cold flowfield of a hydrocarbon fueled model scramjet combustor with a streamwise vortices mixer

This study presents a numerical study of the cold flowfield of a hydrocarbon fueled model scramjet combustor.In order to hold the flame and improve the efficiency of combustion,our strategy of enhancing supersonic mixing and controlling combustion is to use streamwise vortices.The authors devised a new pilot-subsonic-combustor and a streamwise vortices mixer.The model combustor connects directly to a small altitude test-bed.The cool-state through flow tests has been carried out at the same time.Compared to the experiment,the result of the simulation is satisfactory.Meanwhile the formation mechanism of streamwise vortices and their downstream development in the supersonic model combustor flowfield has been investigated.Our computational study indicates that this streamwise vortices mixer generates significant secondary-flows for promoting rapid supersonic flow mixing,while the loss of the total pressure in stream is small.Meanwhile,this paper researches especially the lower isolator inlet Mach number phenomena with a Mach number 1.5 which may be encountered at the subsonic/supersonic transition.It is found that this Mach number may cause flow choke in the ignition of the supersonic model combustor.