Research on cook-off characteristics and multistep thermal decomposition calculation of HMX-based explosive

The multi-point temperature measuring cook-off tests are carried out to investigate the thermal reaction characteristics of HMX/binder/95/5 explosive. The temperature in the mixed explosive is measured from the center to the edge. The changes of temperature caused by β→δ transition of HMX are observed. The cook-off bombs with differently sized HMX/binder/95/5 explosives are test. The influence of charge size on the cook-off process of explosive is studied. The results show that the temperature distributions, phase transitions, ignition times and ignition locations of differently sized explosives are different under the same heating condition. HMX/binder/95/5 explosive violently explodes after ignition. A model of thermal reaction for HMX/binder/95/5explosive is established. The thermal decomposition of explosive is described by the multi-step chemical kinetics mode, and the phase transition of HMX is described by transition state theory. According to the measured T-t curves from multi-point temperature measuring cook-off test, the reaction kinetic parameter of HMX is calibrated. The change of temperature caused by β→δ transition of HMX is calculated. According to the numerical simulations of differently sized cook-off bombs, the calculation accuracy is verified. The prediction calculation of the cook-off processes of explosive is performed. The mass fractions of reactant, intermediates and product during the process of thermal reaction are obtained by calculation.