The structure of an acoustically forced, reacting two-phase jet

An experimental study of the structure of an acoustically forced, reacting two-phase jet was performed. The jet was acoustically forced to control the formation and evolution of large-scale structures in the near field of the jet. Phase-locked data acquisition techniques were used to correlate dropl et statistics and dynamics with features of the large-scale structures. Pha se Doppler interferometry was used to acquire droplet statistics. Planar im aging techniques were applied to document the distribution of droplets with in the jet. The results show that the interaction between droplets and larg e-scale structures leads to a nonuniform distribution of droplets in the re acting jet. The combination of transport effects and droplet evaporation le ads to the formation of droplet clusters. The group combustion behavior of the droplet field was evaluated by estimating the group combustion number f rom experimental data. External sheath burning is present in the early port ion of the flame followed by a transition to external group combustion as c lusters begin to be the dominant feature. Late in the cluster lifetime ther e is a shift to internal group combustion. (C) 2000 by The Combustion Insti tute.