Detonation Front Structure: Variety and Characterization

Abstract

The structure of multifront or cellular detonation waves has been studied using Schlieren, planar laser-induced fluorescence (PLIF) imaging of the OH radical, and soot foils in three mixtures with varying regularity. These are: stoichiometric H_2-O_2 diluted with Ar, stoichiometric H_2-O_2 diluted with N_2, and stoichiometric H_2-N_2O diluted with N_2, all at 20 kPa initial pressure. Very different structures are observed in each mixture. These differences are most striking on the PLIF images, which are used as a starting point for a qualitative discussion and interpretation of the features seen on the Schlieren images and soot foils. It is clear that the detonation propagation mechanism in mixtures with irregular cellular structure may be much more complex than in mixtures with regular cellular structure.