Up-scaling of dsc data of high energetic materials

Abstract

Differential scanning calorimetry (DSC) carried out with few heating rates was applied in the studies of the thermal properties of four energetic materials: EI ® propellant, high explosive PBXW-17, pyrotechnic mixtures with composition B/KNO₃ (50:50) and B/KNO₃ (30:70). DSC signals, after optimization of the baseline, were used for the calculation of the kinetic parameters (KP) of the decomposition process applying advanced kinetic software designed by AKTS. The determination of the kinetic parameters was based on the differential iso-conversional method of Friedman. The correctness of the estimation of KP was checked by the comparison of the experimental and predicted courses of the decomposition.

The slow cook-off experiments of above mentioned energetic materials were carried out with a heating rate of 3.3°C h^–1. For the simulation of the experimental results, the heat balance based on the finite element analysis (FEA) was applied together with the advanced kinetic description of the reaction. The comparison of the experimental and simulated data indicates that applied procedure resulted in a very good prediction of the temperature of the ignition. Application of commonly used, simplified assumptions concerning the mechanism of the decomposition (such as 1^st or n ^th order mechanisms) led to significantly worse prediction of the cook-off temperatures.