Use of simplified chemical kinetics in simulation of combustion and explosions.

摘要

To address the fire and explosion hazards of energetic materials (EMs), it is desired to develop reliable simulation tools to provide costeffective means of investigating potential safety issues and designing hazard mitigation strategies for new EMs, applications and device geometries. The goal of this thesis is to investigate the connection between the thermal decomposition and combustion of EMs and to incorporate the decomposition kinetics into combustion models for large-scale combustion simulations.;Thermal analysis techniques can be used to determine the global thermal decomposition kinetics of EMs. Kinetic parameters can be a useful diagnostic for solving problems in combustion. The presence of impurities in FOX-7, an advanced insensitive explosive, has a big impact to its combustion performance. This has been detected as anomalous changes in decomposition activation energies of the material.;Thermal decomposition kinetic parameters can also be used in combustion models. Such a model has been developed for steady state combustion of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) based on a simplified kinetic scheme for combustion developed by Ward, Son and Brewster. Simulation results using this model reveal some of the dependence of explosion violence on device geometry.;In the interest of the combustion instability of EMs, a nonsteady combustion model has been developed based on the steady state model. This model is computationally efficient and can be used in simulations to predict combustion instabilities caused by the acoustic pressure oscillations in solid rocket motors.;A simple detonation model known as JWL++ has also been implemented in the simulation code. This enables the development of appropriate deflagration-to-detonation computational simulation models in the future research on safety of explosive devices.;This thesis begins with a literature review (Chapter 1) for the kinetic analysis methods of thermal analysis data and the studies of decomposition and combustion of HMX. Chapter 2 presents the kinetic study of thermal decomposition of FOX-7 samples. Chapters 3 and 4 give the detailed descriptions and validations of the steady state and the nonsteady combustion models, respectively. Chapter 5 discusses the implementation of the detonation model. Finally, Chapter 6 concludes the thesis and provides suggestions for the future research.