A Detailed, Finite-Rate Chemical Kinetic Mechanism for Modeling the Thermal Decomposition and Combustion of Gaseous Nitroglycerin

As a step toward developing a state-of-the-art capability for modeling the decomposition and combustion of minimum-smoke rocket propellants and double-base gun propellants, a detailed, finite-rate chemical kinetics mechanism for modeling the thermal decomposition of gaseous nitroglycerin (NGg) was developed and evaluated. Quantum mechanics-based electronic structure methods (QM-ESMs) were employed to characterize the molecular structures of stationary points of minimum energy paths for a network of elementary reactions capable of reducing the parent to small molecules. Thermodynamic properties for the stationary points were derived from the QM-ESM data, and the thermodynamic properties were employed to parameterize formulae for computing rate coefficients for elementary reactions. Those formulae were combined with a previously developed submechanism for modeling the small-molecule reaction chemistry common in the combustion of organic nitrate esters. The integration produced a mechanism comprising 1591 reactions and 229 species that is expected to be suitable for modeling NGs decomposition and combustion over wide ranges of temperature and pressure. To evaluate its validity for conditions of interest, it was integrated with models to simulate NGs deflagration as a function of pressure and its gas-phase decomposition from 150 to 160 C. Reasonable agreement with measured data was observed. Anticipating the mechanisms use for other applications, we provide all its parameters for computing reaction-rate coefficients and species thermodynamic properties.