Unsteady propagation of detonation with multi-stage heat release

Abstract This work numerically studies the propagation characteristics of detonation waves with multi-stage heat releases (MSHR) for stoichiometric dimethyl ether/oxygen (DME/O2) mixtures with carbon dioxide (CO2) addition. Results show that detonation with MSHR is intrinsically unstable and will develop to a new mode. It is found that in the mixtures with mu lti-stage heat release the steady structure on the scales predicted by the ZND theory cannot exist and evolves into a detonation wave with much thinner structure through the particular paths via which the ZND detonation losses its stability. For different MSHR features induced by CO2 addition, two detonation development modes with double- and single-head structures are observed, with the former controlled by the merging of second- and third-stage heat release, while the latter triggered by the second-stage heat release with the fastest heat release rate.