TY - JOUR
T1 - An experimental and kinetic modeling study of the autoignition mechanism of 2-ethylhexyl nitrate combustion
AU - Xie, Jiaxin
AU - Jia, Mengmeng
AU - Bruce, Frederick Nii Ofei
AU - Zhou, Chong Wen
AU - Curran, Henry
AU - Hin, Taufiq Yap Yun
AU - Cheng, Song
AU - Sun, Ce
AU - Qin, Fei
AU - Li, Yang
N1 - Publisher Copyright:
© 2025 The Combustion Institute
PY - 2026/3
Y1 - 2026/3
N2 - 2-Ethylhexyl nitrate (EHN) has attracted attention for its high reactivity, making it a promising candidate for use in propellants and as a combustion-enhancing fuel additive. To gain a fundamental understanding of its combustion behavior and support its practical application in advanced propulsion systems, it is essential to develop an accurate and reliable chemical kinetic model. In this study, ignition delay times (IDTs) of EHN/O₂/N₂ mixtures were systematically measured using a high-pressure shock tube. Experiments were conducted over a temperature range of 900–2000 K, at pressures of 5 and 10 bar, and under equivalence ratios of 0.5 and 1.0. The results clearly demonstrate the characteristic two-stage ignition behavior of EHN. Moreover, the IDTs were found to be highly sensitive to changes in both equivalence ratio and pressure. In the theoretical investigation, the initial decomposition pathways of EHN were systematically explored using high-level quantum chemical calculations at the QCISD(T)/CBS//M06–2X/6–311++G (d,p) level. The results indicate that cleavage of the O–N bond is the dominant reaction channel. A detailed kinetic model for EHN was developed based on the C3MechV3.3 reaction mechanism. The model predictions show good agreement with experimentally measured IDT. Furthermore, based on the current kinetic model, sensitivity, flux, and OH radical rate of production analyses were performed to identify key controlling steps and characterize radical-driven kinetics. The results show that in the first stage of ignition, over 90% of EHN is consumed via O–N bond cleavage, producing the 2-ethylhexoxy radical (EHO) and NO₂, which spontaneously initiate the NO₂–NO catalytic cycle and significantly enhance the system's initial reactivity. In contrast, during the second stage, the chain-branching reaction H + O₂ → O + OH becomes dominant and serves as the primary driving force behind the rapid acceleration of system reactivity.
AB - 2-Ethylhexyl nitrate (EHN) has attracted attention for its high reactivity, making it a promising candidate for use in propellants and as a combustion-enhancing fuel additive. To gain a fundamental understanding of its combustion behavior and support its practical application in advanced propulsion systems, it is essential to develop an accurate and reliable chemical kinetic model. In this study, ignition delay times (IDTs) of EHN/O₂/N₂ mixtures were systematically measured using a high-pressure shock tube. Experiments were conducted over a temperature range of 900–2000 K, at pressures of 5 and 10 bar, and under equivalence ratios of 0.5 and 1.0. The results clearly demonstrate the characteristic two-stage ignition behavior of EHN. Moreover, the IDTs were found to be highly sensitive to changes in both equivalence ratio and pressure. In the theoretical investigation, the initial decomposition pathways of EHN were systematically explored using high-level quantum chemical calculations at the QCISD(T)/CBS//M06–2X/6–311++G (d,p) level. The results indicate that cleavage of the O–N bond is the dominant reaction channel. A detailed kinetic model for EHN was developed based on the C3MechV3.3 reaction mechanism. The model predictions show good agreement with experimentally measured IDT. Furthermore, based on the current kinetic model, sensitivity, flux, and OH radical rate of production analyses were performed to identify key controlling steps and characterize radical-driven kinetics. The results show that in the first stage of ignition, over 90% of EHN is consumed via O–N bond cleavage, producing the 2-ethylhexoxy radical (EHO) and NO₂, which spontaneously initiate the NO₂–NO catalytic cycle and significantly enhance the system's initial reactivity. In contrast, during the second stage, the chain-branching reaction H + O₂ → O + OH becomes dominant and serves as the primary driving force behind the rapid acceleration of system reactivity.
KW - 2-ethylhexyl nitrate
KW - Chemical kinetic modeling
KW - High-pressure shock tube
KW - Ignition delay times
KW - Quantum chemical calculation
UR - https://www.scopus.com/pages/publications/105026178118
U2 - 10.1016/j.combustflame.2025.114743
DO - 10.1016/j.combustflame.2025.114743
M3 - 文章
AN - SCOPUS:105026178118
SN - 0010-2180
VL - 285
JO - Combustion and Flame
JF - Combustion and Flame
M1 - 114743
ER -