管道中不同形状悬置障碍物与火焰相互作用的实验观察

研究管道内火焰与障碍物相互作用过程对预防因燃烧失稳导致爆炸事故具有非常重要的意义.利用高速阴影照相系统对方形管道内火焰流经不同形状的障碍物时所产生的失稳加速及变形进行了实验测试.障碍物置于管道内前端的中央位置,其形状分别为圆柱,方柱以及三角形柱体,实验表明火焰阵面在临近障碍物时会产生变形,其形状与障碍物形状相关.另外,由于障碍物与管道壁面会形成不同形状的火焰通道,从而使火焰在通道内的加速程度不同,在障碍物后形成不同的阵面结构.火焰在绕过障碍物后,因受到未燃气产生的尾流低压旋涡影响而在障碍物后方中向管道中心线翻转.

Experimental investigations on the interaction between the flame and various solid obstacles in the middle of duct

It is very important to investigate the interaction between flame and obstacles in a pipe for the prediction of its induced explosion accidents in chemical process of industries.With a high speed shadowgraph system,the acceleration and distortion of flame front were visualized when it propagates in a pipe with different obstacles mounted in the axial center.Three obstacles,square,circular and equilateral triangle cylinder were employed respectively.Our results show that different degrees of flame distortion occur when the flame propagates near different obstacles.Furthermore,the degree of flame acceleration is also related with the shape of the tunnel which consists of the pipe and obstacle walls.In addition,we also found that the flame overturns toward the axial center due to the attraction of the low pressure of vortices behind the obstacles caused by the move of unburned gases.