Diffraction of Combustion Waves in a Two-Dimensional Channel. Part II

Despite numerous studies, many aspects of the ignition and propagation of combustion and detonation waves in combustible mixtures remain insufficiently studied, which complicates the scientifically based control of these processes. The first part of this work presented new experimental data on the various stages of ignition and on flame front propagation in a flat (two-dimensional) channel of constant cross section. This paper presents the results of the little-studied area of combustion wave behavior in a channel with varying geometric dimensions (so-called flame diffraction). The characteristic processes involved in the behavior of a turbulent flame propagating from a narrow to a wide channel have been established: from flameout and the disappearance of the front glow with incomplete combustion of the mixture in the wide channel to the occurrence of new explosive microcenters due to the development of instabilities of the expanding flame and collisions of turbulent flame tongues, leading to the formation of detonation-like waves.