Chemistry Modeling Effects on the Interaction of a Gaseous Detonation with an Inert Layer

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Influence of the chemical modeling on the quenching limits of detonation waves confined by an inert layer

The effect of chemistry modeling on the flow structure and quenching limits of detonations propagating into reactive layers bounded by an inert gas is investigated numerically. Three different kinetic schemes of increasing complexity are used to model a stoichiometric H2-O2 mixture: single-step, three-step chain-branching and detailed chemistry. Results show that while the macroscopic characteristics of this type of detonations (e.g. velocities, cell-size irregularity and leading shock dynamics) are similar among the models tested, their instantaneous structures are significantly different before and upon interaction with the inert layer when compared using a fixed height. When compared at their respective critical heights, hcrit (i.e. the minimum reactive layer height capable of sustaining detonation propagation), similarities in their structures become apparent. The numerically predicted critical heights increase as hcrit,Detailed << hcrit,1-Step < hcrit,3-Step. Notably, hcrit,Detailed was found to be in agreement with experimentally reported values. The physical mechanisms present in detailed chemistry and neglected in simplified kinetics, anticipated to be responsible for the discrepancies obtained, are discussed in detail

Quenching limits and dynamics of multidimensional detonation waves confined by an inert layer

International audienceTwo-dimensional inviscid simulations are conducted to assess the effect of chemistry modeling on the detonation structure and quenching dynamics of detonations propagating into a semiconfined medium. Two different simplified kinetic schemes are used to model the chemistry of stoichiometric H 2-O 2 mixtures: single-step and three-step chain-branching chemistry. Results show that the macroscopic characteristics of this type of detonations (e.g. detonation velocity and cell size irregularity) are very similar for both models tested. However, their instantaneous structures are very different before and upon interaction with an inert layer. Specifically, the minimum reactive layer height, h crit , capable of sustaining detonation propagation is larger when a more realistic description of the chemistry is used. This outcome suggests that the quenching limits predicted numerically are dependent on the choice of chemical modeling used