Investigation of transient PVC dynamics in a strongly swirled spray flame using high speed planar laser imaging of SnO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si9.svg"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math> microparticles

The Precessing Vortex Core (PVC) dynamics is investigated in a laboratory scale swirl stabilized spray combustor. This helical structure commonly found swirling flows used to stabilize flames many combustion systems has notable impact on the of flow, and flame formed by injector unit. PVC examined combining laser sheet illumination front tracers filmed with high speed camera, Proper Orthogonal mode Decomposition (POD) wavelet analysis. In distinction most applications illumination, which flow seeded oil droplets that vanish at relatively low temperature when crossing front, present implementation relies micronic tin oxide (SnO2) particles much higher temperatures. well suited where fresh reactants are already or hot gases recirculated as case injection configurations. A first set experiments carried out stagnation point premixed determine (Tv≈1770K) dioxide identify chemical reaction controls this process. Because light scattered solid quite intense, method can be very repetition rates. It then applied 100 kHz frame rate configuration situation combustor does not exhibit thermo-acoustic instabilities. takes form double helix brief intermittent switching single, followed triple helicoidal geometry. POD-wavelet analysis indicates these moments correspond flashback events randomly occur during characteristics change for few milliseconds time. second chamber length augmented giving rise instability coupled longitudinal acoustic frequency an order magnitude lower than frequency. planar slices reveal large cyclic motion edge inner recirculation zone. modulated both amplitude frequency, modulating corresponding thermoacoustic oscillation. also observed random manner.