It is found that the liquid kerosene of injection upstream cavity could finish the process of atomization and evaporation in short distance , and enter into cavity through convection . aft wall is the primarily area of flame holding in cavity , and the only area when near the lean blowout limit , flame in area of fore wall are spread from it . cavity shear layer in reaction flow angle greatly to the main flow direction , and couldn ’ t reattach to aft wall anymore , it appears great difference in characteristics of cavity flowfield between non - reaction and reaction state 研究发现:凹腔上游喷注的液体燃料能够迅速雾化、蒸发,并在较短距离内依靠对流输运过程进入凹腔内部;凹腔后壁始终是凹腔火焰驻留的主要区域,在贫油极限时,也是唯一区域,并存在明显的火焰由后壁向前壁的传播过程;燃烧状态下的凹腔剪切层以较大角度向下游主流发展,不再附着于凹腔后壁,与冷流中的凹腔流场特征相差较大。
The shearing layer is carried by the jet and the eddy is formed because of the instability and selective amplification of shearing layer which will propagate to the downstream . as the eddy impacts the impinging wall , a wave of pressure disturbance with certain frequency is induced . this wave then propagates to the upstream with high speed , and results in the overlap and amplification of the waves when the frequencies of them are close with each other 当前喷嘴流束中的不稳定扰动波在穿过腔内的剪切层时，剪切层对其有选择放大作用，形成涡环结构，剪切流动中涡环与碰撞壁撞击，在碰撞区域产生压力扰动波并向上游反射，在上游剪切层分离处诱发新的扰动的产生，当新扰动与原扰动匹配时，射流上游就被不断地受到周期性激励，腔内就产生流体自激振荡并在后喷嘴出口形成脉冲射流。
