Experimental Investigation Of Solid And Fluidic Obstacle Interactions With Premixed Laminar Flames

Abstract

There have been extensive research efforts to control the onset of detonation through the Deflagration-to-Detonation transition (DDT). This process occurs when a flame rapidly accelerates, produces a leading shock wave that compresses the reactant mixture and generates a spontaneous detonation wave. To more efficiently induce DDT, numerous studies have demonstrated enhanced flame acceleration through the generation of inflow turbulence. Conventional turbulence induction has been achieved using solid obstacles within the flow that create recirculation regions, reflect acoustic waves for shock flame interactions and induce interfacial hydrodynamic instabilities that corrugate the flame boundary. The present work is an experimental investigation that explores the flame acceleration effects of a propagating flame interacting with a solid obstacle and a fluidic slot jet. The jet is a novel technique that exposes the flame directly to highly turbulent reactants. The prevalent mechanisms driving the flame-fluidic jet interaction are shown to enhance turbulent reactant transport due to high levels of jet turbulence and jet entrainment within the combusted products. The study explores the effect of various main and jet equivalence ratios to extend the experimental database of turbulent propagating flame interactions and identify the underlying physics during these dynamic flame interactions. Schlieren photography, a non-invasive optical diagnostic, is used to visualize the flow field, identify turbulent structures, and classify turbulent interaction mechanisms throughout the stages of the turbulent interaction. Higher equivalence ratios are found to display higher final flame front propagation velocities. Further exploration of the dynamic flame interaction in the various cases demonstrate turbulence growth, generation of flame vortices, flow restriction, jet deflection, and other mechanisms that drive higher burning rates. The study works towards enhancing the understanding of these complex physical mechanisms that are critical to the process of flame acceleration to detonation by isolating and adjusting the various parameters of the propagating laminar flame interaction.

Publication Date

1-1-2017

Publication Title

53rd AIAA/SAE/ASEE Joint Propulsion Conference, 2017

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.2514/6.2017-4832

Socpus ID

85088069719 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85088069719

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