Study on the correlation mechanism between carbon evolution and energy release in oxygen-deficient explosives

For explosives with a pronounced negative oxygen balance, the condensation and phase transition of carbon in both the chemical reaction zone and the isentropic expansion zone play a critical role in determining the Chapman–Jouguet (CJ) detonation parameters and the overall energy release characteristics. Conventional phenomenological reaction models generally neglect the kinetics of carbon condensation and its associated phase transformations, thereby limiting their ability to rigorously capture the additional energy release arising from this process. In this work, we extend a phenomenological reaction-rate framework by incorporating the Shaw–Johnson condensation kinetics model, coupled with the temporal evolution of the free energy of condensed carbon products, to investigate the secondary energy release behavior induced by carbon coagulation. Three representative formulations—HMX-1 (HMX:TATB:TNT:binder = 87:7:2:4), TATB-1 (TATB:binder = 95:5), and TATB-2 (TATB:HMX:binder = 80:15:5)—were systematically examined through thermodynamic analysis, kinetic simulations, and flyer-plate experiments. The calibrated model parameters were found to faithfully reproduce the kinetics of carbon condensation and quantify its contribution to flyer acceleration and detonation performance. Deviations between simulations and experimental measurements remain within 10% for both the first-jump velocity and the entire flyer acceleration profile. • Thin-flyer driven experiments were conducted to isolate the effects of initial shock and subsequent expansion work in HMX- and TATB-based explosives. • A Shaw–Johnson condensation kinetics model was integrated with the JWLM EOS to quantify secondary energy release from condensed-phase carbon. • Calibrated JWLM parameters reproduced flyer velocity histories with deviations below 10%, validating the model’s predictive accuracy. • The study establishes a quantitative link between microscopic carbon evolution and macroscopic energy release, providing new insights for improving EOS models and guiding insensitive explosive design.