The secondary air flow of a swirl stabilised burner was oscillated at a frequency of 350 Hz for swirl numbers of 0.66, 0.7 and 0.81. Time dependent phase-Doppler velocimentry quantified the spray and the air flow and chemiluminescence of the CH radicals the shape and area of kerosene fuelled flames. The results suggest that the imposed oscillations shed a series of vortex rings at the burner exit with the oscillation frequency, increasing mixing and distorting the reaction zone, and potentially reducing the NO_x emissions. The flame lifted off for a critical amplitude, which increased with swirl number, due to the translation of the recirculation zone at a downstream position leading to increased stretch rate, evaluated frm the temporal variation of the flame area, and local extinction in the near burner region.
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