Time-resolved particle image velocimetry in confined bluff-body burner flames

Time-resolved particle image velocimetry was applied to a non-premixed turb ulent flame generated by a confined bluff-body burner. Original synchroniza tion of the experimental setup allowed us to obtain sequences of consecutiv e instantaneous velocity fields. Experimental limitations of the applicatio n of PIV in industrial-like burners are pointed out, requiring the developm ent of specific preprocessing of the particle images associated with an ori ginal iterative procedure for cross-correlation calculation. Temporal evolu tion of coherent structures in the recirculation zone generated by the wake effect of the bluff body is visualized on sequences of consecutive velocit y fields. Characterization of the temporal evolution of the stagnation poin ts encountered in the recirculation zone reveals low-frequency movements of their axial locations.