Experimental and kinetic modeling of JP-10 ignition in nitrous oxide

JP-10/N₂O is a promising replacement for the conventional hydrazine-based propellants due to its non-toxic nature and high energy characteristics. It is crucial to understand the auto-ignition behavior of JP-10 with N₂O, which, however, remains insufficiently characterized. In this study, ignition delay times (IDTs) and OH concentration time histories of JP-10/N₂O/Ar mixtures were obtained behind reflected shock waves under a wide range of operating conditions. Specifically, experiments were performed over temperatures of 1417–1823 K, at pressures of 2.5–8.5 atm, with fuel concentrations of 0.06%–0.24%, and under equivalence ratios of 0.5, 1.0, and 2.0. The experimental results indicate that IDTs of JP-10 oxidation in N₂O are longer than those in O₂ under the same conditions. Furthermore, the IDTs of JP-10/N₂O/Ar mixtures exhibit a strong dependence on the temperature, pressure, and equivalence ratio. A detailed chemical kinetic model for JP-10 oxidation in N₂O is developed by integrating a revised HyChem model with a NOx mechanism. Predictions from the kinetic model show good agreement with measured IDTs across most experimental conditions, which accurately capture the promoting effects of increasing pressure and fuel concentration on the ignition despite minor discrepancies under elevated pressure conditions. Rate-of-production analysis reveals that the initially formed OH is primarily consumed by reactions with JP-10, driving fuel decomposition into small intermediates. Subsequently, ignition occurs as the radical pool accumulates and the exothermic propagation reaction H + N₂O = N₂ + OH drives the system toward thermal runaway. According to the sensitivity analysis, reactions of N₂O + M = N₂ + O + M and N₂O + H = N₂ + OH are identified to play dominant roles in the ignition of JP-10 in N₂O. This work provides essential experimental data and a validated chemical kinetic model to support the development of JP-10/N₂O as a non-toxic, high-performance propellant alternative. Novelty and significance statement As a storable and environmentally benign oxidizer, N₂O combined with the high-energy-density hydrocarbon fuel JP-10 presents a promising, non-toxic alternative to the conventional hydrazine-based propellants. A foundational understanding of the ignition characteristics of the JP-10/N₂O system is essential for the design of next-generation propulsion systems. However, its auto-ignition behavior has not yet been systematically characterized. To address this gap, this study presents the first comprehensive investigation of the JP-10/N₂O auto-ignition through a combined experimental and kinetic modeling approach. It enables a systematic analysis of the effects of temperature, pressure, and equivalence ratio on the ignition of JP-10/N₂O. The quantitative data and empirical correlations established for the ignition delay time in this work offer practical guidance for the development of next-generation liquid rocket engines utilizing JP-10/N₂O propellants.