Kinetic Modeling of Liquid Phase RDX Thermal Decomposition Process and its Application in the Slow Cook‐Off Test Prediction

Abstract RDX is an important and commonly used energetic material. The understanding thermal decomposition process of RDX is of great significance for the safety of its production, storage, and use. However, due to the coupling of phase transition and thermal decomposition process, a multi‐step kinetic model including melting and decomposition process has not been established so far, which is not helpful to the prediction of its thermal behavior in different conditions. In this paper, Differential Scanning Calorimetry was used to measure the decomposition characteristics of RDX at different heating rates. A four‐step consecutive reaction model A→A liq →B→C→D was established to depict the melting and decomposition process. Then quench and reheat experiments were performed to determine the types of each step, where the reaction types are autocatalytic except that the step of B→C is an N‐order reaction. The model was used to predict the result of slow cook‐off test. It was found that the predicted time of thermal explosion is 0.2 h earlier than the experiment and the onset temperature is 0.6 °C smaller than experiment, which verifies the rationality of the kinetic model.