Influence of chemical initiators on the pyrolysis and coking behavior of exo-THDCPD: experimental insights and ReaxFF molecular dynamics simulations

초록

Coke deposition resulting from fuel pyrolysis remains a critical challenge in regenerative cooling channels of hypersonic vehicles. In this study, the pyrolysis behavior and coke formation of exo-tetrahydrodicyclopentadiene (exo-THDCPD), a major constituent of JP-10, were investigated under supercritical conditions (615 °C and 40 bar) using four chemical initiators: di-tert-butyl peroxide (DTBP), 2,2,6,6-tetramethylpiperidine (TEMPO), triethylamine (TEA), and cumene hydroperoxide (CHP). The influence of initiator chemistry on heat-sink capacity, fuel conversion, product distribution, and coke yield was quantified to assess their effectiveness in suppressing coke formation while sustaining endothermic decomposition. Among the tested initiators, TEA exhibited the highest heat-sink capacity of 949.2 Btu/lb (2207.8 kJ/kg) together with the lowest coke yield of 11 mg. ReaxFF-based reactive molecular dynamics (MD) simulations were used to resolve initiator-dependent bond cleavage processes and the early evolution of polycyclic aromatic hydrocarbon (PAH) precursors. In the presence of TEA, the formation of PAH precursors was markedly suppressed, consistent with the reduced yields of aromatic species and coke observed experimentally. The experimental observations and atomistic simulations demonstrate that initiator-derived radical chemistry modifies dominant pyrolysis pathways, leading to reduced coke formation under supercritical regenerative cooling conditions. © 2026 Elsevier Ltd.

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