ps-LIF measurements of minor species concentration in a counterflow diffusion flame interacting with a vortex

Interactions of vortices and flame fronts may be considered as the basic st ructural elements of turbulent combustion. Additionally, they play an impor tant role in flame instabilities as well as extinction and ignition process es. An ideal geometry to study these interactions is the counterflow diffus ion burner with an additional actuator-driven nozzle for the generation of a vortex ring. This burner has already been well-characterized by other met hods including CARS, LDA and PLIF We present first quantitative measurement s of minor species concentration in this flame using a short-pulse laser an d time- and spatially resolved fluorescence detection with a streak camera. Quench-ft re OH concentrations are obtained by analysis of the time-resolv ed profiles. The high power density of the laser pulses allowed linewise de tection of hydrogen using a three-photon excitation scheme. Simultaneously, shape and position of the vortex was monitored using two-dimensional detec tion of flame emissions. Spatially resolved concentration profiles of H and OH are presented for different interaction heights and times in the vortex . For steady flames, comparisons with model calculations are shown.