Interpretation of the double cellular structure of detonation in gaseous nitromethane

Calculations of the reaction zone of the detonation of gaseous nitromethane , either pure or diluted with oxygen, in the range of equivalence ratio Phi between 0.1 and 1.75, show that for 1.75 greater than or equal to, Phi > 1 .3 the chemical energy is released in two main successive reaction steps ch aracterized by very different induction times. These results corroborate th e experimental observations of two levels of cellular structures in the som e range of equivalence ratios. To our knowledge this work is the first whic h deals with the problem of nonmonotonous chemical energy release behind th e leading shock of a detonation wave. (C) 2001 Academie des sciences/Editio ns scientifiques et medicales Elsevier SAS.