Development of Flame Holding System in Scamjet by Flame Jet

为了发展超燃冲压发动机的火焰稳定系统，通过对火焰射流自由基的测量，研究了火焰射流的点火机理，得到了以下结论。(1)从火焰喷射中的CH发射和OH荧光测量中揭示，从孔口发出的活性物质的周期大概由由传统汽车点火电路产生的火花放电的持续时间决定，即几毫秒的量级。(2)在包含射流轴线和垂直于射流轴线的两个平面上，射流的OH荧光图像中都观察到了大尺度的涡旋结构。(3)火焰射流发生器腔体中采用较浓混合物时，射流OH荧光的面积和强度较大且较高。(4)射流OH荧光的面积和强度受腔体体积和小孔直径的影响。

In order to develop the flame holding system in Scramjet, the ignition mechanism of Flame Jet was investigated by measuring radicals in the jet, and the following conclusions were obtained.(1) It was revealed from both CH emission and OH fluorescence measurements in Flame Jet that the period of active species issuing from the orifice presumably be governed by the duration of spark discharge produced by a conventional automobile ignition circuit, that is of an order of a few milliseconds.(2) The large scale vortex structure was observed in the images of OH fluorescence of the jet in both planes ; the plane contained the jet axis and that perpendicular to the jet axis.(3) The area and the intensity of the OH fluorescence of the jet were larger and higher with the use of richer mixtures in the cavity of Flame Jet generator.(4) The area and the intensity of the OH fluorescence of the jet were affected by the cavity volume and the orifice diameter.