Effect of hydroxyl radical precursor addition on LTC-affected detonation in DME–$$\hbox {O}_{{2}}$$–$$\hbox {CO}_{{2}}$$ mixtures

Abstract

The effects of hydrogen peroxide ( $$\hbox {H}_{2}\hbox {O}_{2}$$ ) and tert-butyl hydroperoxide (TBHP), both hydroxyl radical precursors, on the characteristic length-scales of low-temperature-chemistry-affected (LTC-affected) detonation propagating in dimethyl-ether–oxygen–carbon-dioxide (DME– $$\hbox {O} _{2}$$ – $$\hbox {CO}_{2}$$ ) mixtures were investigated using the Zeldovich–von Neumann–Doring model. A three-step energy release is observed when the $$\hbox {CO}_{2}$$ content is above a critical value, with and without $$\hbox {H}_{2}\hbox {O}_{2}$$ or TBHP addition. The effect of these two additives on the energy release dynamics and chemical kinetics has been analyzed in detail. The $$\hbox {H}_{2}\hbox {O} _{2}$$ addition induces a similar reduction of the different induction zone lengths, as well as an increase of the energy release rate. The addition of TBHP induces both a thermal and a chemical effect. Thermally, since the effective equivalence ratios of the mixtures are higher, higher Mach numbers and higher von Neumann temperatures are achieved. Chemically, an “LTC chain propagation loop” leads to a significant decrease of the induction zone length along with a substantial increase of the energy release rate, especially for the first stage of energy release. Hence, TBHP seems to be a promising additive for experimentally observing LTC-affected detonation with multi-stage energy release.