Turbulent flame augmentation using a fluidic jet for Deflagration-to-Detonation

Detonation is a high energetic mode of pressure gain combustion that exploits total pressure rise to augment high flow momentum and thermodynamic efficiencies. Detonation is initiated through flame acceleration driven by turbulence interaction and induction for Deflagration-to-Detonation Transition (DDT). There is a broad desire to unravel the physical mechanisms of turbulence induced DDT. The study examines the role of turbulence induced by a fluidic jet on turbulent accelerating flames. The investigation aims to classify the turbulent flame dynamics and temporal evolution of the flame stages throughout the turbulent regimes. The flame-flow interactions are experimentally studied in a detonation facility using high-speed particle image velocimetry (PIV) and Schlieren imaging. The analysis explores the local turbulence and flame acceleration mechanisms that result from the high level of turbulent transport induced by the jet. Higher flame acceleration is observed for the turbulent flame relative to the laminar flame. The turbulent flame experiences high propagation of turbulence intensities in the lower flame boundary. An increase in vorticity generation, velocity fluctuation, and turbulent strain-rate is experienced throughout the interaction. The turbulent flame regime is characterized showing an evolution between the thin-to-broken reactions.