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Flame-Turbulence Interaction for Deflagration to DetonationChambers, Jessica 01 January 2016 (has links)
Detonation is a high energetic mode of pressure gain combustion that exploits total pressure rise to augment high flow momentum and thermodynamic cycle efficiencies. Detonation is initiated through the Deflagration-to-Detonation Transition (DDT). This process occurs when a deflagrated flame is accelerated through turbulence induction, producing shock-flame interactions that generate violent explosions and a supersonic detonation wave. There is a broad desire to unravel the physical mechanisms of turbulence induced DDT. For the implementation of efficient detonation methods in propulsion and energy applications, it is crucial to understand optimum turbulence conditions for detonation initiation. The study examines the role of turbulence-flame interactions on flame acceleration using a fluidic jet to generate turbulence within the reactant flow field. The investigation aims to classify the turbulent flame dynamics and temporal evolution of the flame stages throughout the turbulent flame regimes. The flame-flow interactions are experimentally studied using a detonation facility and high-speed imaging techniques, including Particle Image Velocimetry (PIV) and Schlieren flow visualization. Flow field measurements enable local turbulence characterization and analysis of flame acceleration mechanisms that result from the jet's high level of turbulent transport. The influence of initial flame turbulence on the turbulent interaction is revealed, resulting in higher turbulence generation and overall flame acceleration. Turbulent intensities are classified, revealing a dynamic fluctuation of flame structure between the thin reaction zone and the broken reaction regime throughout the interaction.
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