A Lagrangian view of flame-vortex interaction during turbulent side-wall quenching using high-speed OH-LIF and PIV

Flame-vortex interactions have been suggested to play an important role in flame-wall interactions (FWI). This study presents an experimental investigation of flame-vortex interactions and their influence on flame quenching. Experiments are conducted in a side-wall quenching (SWQ) burner with V-flame configuration. Simultaneous high-resolution particle image velocimetry and OH laser induced fluorescence are conducted to study the flame-flow-wall dynamics under turbulent FWI conditions. Reynolds decomposition is used to provide a Lagrangian reference frame relative to the ensemble-mean velocity field to visualize the evolution of coherent turbulent vortical structures. These vortical flow structures are correlated with regions of elevated swirling strength in the instantaneous velocity field. Three classifications of flame-vortex interaction are identified. One of these classifications emulates a flame-vortex interaction mechanism recently proposed in the literature. This particular flame-vortex interaction reveals a vortex that emanates from the burnt gas and moves quickly towards the wall. The vortex impacts the wall, where local flame quenching occurs and the flame transitions from a head-on quenching (HOQ) to a SWQ flame topology. After quenching, the vortex remains next to the wall and directly above the flame tip as the flame progresses downstream. Each flame quenching event observed in the data exhibits this flame-vortex interaction. This work evaluates the kinematic attributes of the vortex and reveals the tendency of the vortex to push the flame closer to the wall, where the flame experiences flame quenching. Alongside previous DNS studies, this work shows that flame-vortex interactions are phenomenological features that influence flame quenching, as well as heat and mass transport near the wall.