Flame-turbulence interaction of laminar premixed deflagrated flames

The demand for higher combustion efficiency and performance is attainable through pressure gain combustion. Pressure gain combustion exploits the pressure rise for high flow momentum and pressure augmentation. One possible mechanism for detonation is turbulence generation and induction to augment the deflagrated flame acceleration. The study examines the interaction mechanisms of the laminar deflagrated flame with turbulence induced by a fluidic jet, composed of a transverse slot. The mechanisms of the jet including, flame-flow restriction, jet entrainment, turbulent transport, and recirculation are examined to determine the flame-turbulence interaction modes and their influence on the propagating deflagrated flame. The flame interaction and acceleration are compared to that induced by traditional solid obstacles. The flame structural dynamics and reacting flowfield are characterized using simultaneous high-speed PIV and chemiluminescence measurements. Additionally, high-speed Schlieren is used for visualizing the interaction features. Higher flame acceleration is observed for the fluidic jet relative to the obstacle. The flame interaction with the jet turbulence is dominated by a cross-stream high turbulent transport mechanism; whereas, the interaction for the obstacle is driven by Kelvin-Helmholtz and Rayleigh -Taylor instabilities. The obtained results show the dynamic flame evolution phenomenon of the local flame regime (laminar-corrugated flamelet-thin reactions). (C)2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.