Calibration of Parameters in Beta-Delta HMX Phase Transformation Kinetics Using Computer Simulations

Wemhoff, A. P. ; Burnham, A. K.

Lawrence Livermore National Laboratory

关键词: Calibration;    X-Ray Diffraction;    Computerized Simulation;    37 Inorganic, Organic, Physical And Analytical Chemistry;    Kinetics;   

DOI  :  10.2172/888593
RP-ID  :  UCRL-TR-218130
RP-ID  :  W-7405-ENG-48
RP-ID  :  888593

美国|英语

来源: UNT Digital Library

【 摘 要 】

The kinetics of the beta-delta solid-solid phase transformation of HMX (nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) were modeled in ALE2D using four similar equilibrium-inhibited nucleation-growth models: a reversible set of Arrhenius kinetics following a LANL model, and three sets of kinetics derived based on an autocatalytic model using the bidirectional reaction formalism. The parameters for the bidirectional kinetics models were calibrated using simulations of two experimental setup scenarios where experimental data is available: 165 C XRD and SITI. In this calibration, the transition enthalpy and activation energy values were kept constant, while the frequency factors were iterated to achieve results similar to those provided by the experiments. This process yielded six unique sets of kinetic parameters that describe the phase transformation: a pair of sets for each of the three bidirectional kinetics models. The models calibrated using 165 C XRD data showed good agreement with LX-04 STEX experimental results, while the SITI-based models were in good agreement with the LANL model and PBX-9501 STEX experimental data. These bidirectional models were also shown to require less computational effort than the LANL model.