Vortex-Flame Interaction of Spark-Ignited Flame with Coherent Structure in the Plane Premixed Shear Flows. Active Control of Coherent Structure Property by Acoustic Excitation.

Abstract

In order to elucidate the enhancement mechanisms of turbulent flame propagation, it is indispensable to examine and clarify the detailed process of vortex-flame interaction. This is because that the vortex-flame interaction constitutes one of the key processes to promote flame propagation velocity. In this investigation a spark ignited flame is optically observed and examined, which is initiated and propagating in the coherent structure in the plane premixed shear flows. In this paper, as the first step, characteristics of coherent structure without combustion, such as the eddy spacing and diameter are actively controlled using acoustic excitation. Varying the setting conditions of the plane shear flow also varies the convection and tangential velocities. It is found that the acoustic excitation enables the formation of coherent structure having a relatively wide range of properties in the plane shear flows, indicating the possibility to realize the vortex flame interaction under the practical and complicated combustion conditions.