Numerical Study of Blast Initiation of Detonation Using a Two Step Chemical Kinetics Model

Abstract

The effect of chemical reactions on the blast initiation of detonation in gaseous media has been investigated in this paper. Analytical method is based on the numerical solution of onedimensional reactive Euler equations. So far, analyses on the blast initiation of detonation have modeled the combustion process as a one-step chemical reaction, which follows the Arrhenius rate law. Previous studies indicate that one-step model cannot predict single critical initiation energy. These results contradict with the experimental observation that a distinct value of critical initiation energy exists, below which no detonation occurs. Two-step chemical kinetics has been utilized in the present investigation. In two-step kinetics, first step is an induction step, while the chemical energy is released in second step via Arrhenius mechanism. With variation of activation energy in these two steps, the effect of induction length and energy release can be studied. This model predicts three regimes of blast initiation of detonation that have been observed in experimental observation. On the other hand, like one-step model, the present model cannot predict a limit for the initiation energy.