烟尘形态法研究线涡内的平面扩散火焰
An experimental study of the interaction of a planar diffusion flame with a line vortex is presented. A planardiffusion flame is established between two coflowing, equal velocity streams of acetylene diluted with nitrogenand air. A line vortex is generated on demand by momentarily pulsing one of the flow streams by way of electromagneticactuation of a piston in the flow apparatus. The flame–vortex interactions are diagnosed by planarlaser-induced incandescence for soot yield and by particle image velocimetry for vortex flow characterization. Theresults show that soot formation and distribution are influenced by the reactant streams from which vortices areinitiated. The vortices interacting with the flame from the air side produce more soot and soot is distributed in andaround the vortex core in diffuse layers. In contrast, topography of soot in vortices interacting from the fuel sideis such that soot is confined to thinner layers around the vortex core which does not contain any soot. The flamecurvature is found to influence the local soot production with the flame regions convex to the fuel side containingmore soot locally. It is also found that the overall soot yield is less sensitive to the vortex strength and is of lowermagnitude when vortex is spun from the fuel side. The knowledge of this type of asymmetry in soot yield inflame–vortex interactions is useful for combustion engineering and design of practical devices.