Diffraction of Combustion Waves in a Two- Dimensional Channel. Part II
A. A. Vasilyev1,2, A. A. Boriskin1, V. A. Vasilyev1
1Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: spark ignition, critical ignition energy of a mixture, laminar and turbulent combustion, normal flame speed, characteristic combustion instabilities, combustion-to-detonation transition, flame diffraction, rarefaction waves
Abstract
Despite extensive research, many aspects of ignition and propagation of combustion and detonation waves in combustible mixtures remain poorly understood, complicating scientifically sound control of such processes. The first part of this paper presented new experimental data on various stages of ignition and flame front propagation in a flat (two-dimensional) channel of constant cross-section. This paper presents results on the little-studied area of combustion wave behavior with changing channel geometric dimensions (so-called flame diffraction). Characteristic processes in the behavior of a turbulent flame as it transitions from a narrow channel to a wide one are established: from flame breakdown and loss of front glow with incomplete combustion of the mixture in a wide channel to the emergence of new explosive microcenters due to the development of expanding flame instabilities and collisions of turbulent flame tongues, leading to the generation of detonation-like waves.
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