Oxy-Acetylene Detonations : 1st Report, The Transition Phenomena Associated with Soot Formation

Abstract

This paper describes a study of peculiar phenomena in fuel-rich oxy-acetylene detonations. The detonation wave and the accompanying soot-formation were observed by a high speed streak camera. The pressure and particle velocity changes in the expansion wave were measured and compared with theoretical predictions. The effect of an additive which is thought to accelerate the soot-formation was investigated. The following results were obtained. (1) In the fuel-rich region, fluctuations in wave velocities are observed, and the velocity switches from one theoretical value to another with the change in equivalence ratios. (2) A shock wave following the detonation is formed with the accumulation of the compression waves generated by the soot-formation. (3) The pressure and particle velocity changes in the expansion wave agree with the theory based on the assumption that the expansion wave is a centered simple wave. (4) With a small amount of benzene, fluctuations in velocities are no longer observed and the transition occurs at lower equivalence ratios.