Shock simulations of a single-site coarse-grain RDX model using the dissipative particle dynamics method with reactivity

• Main Authors: Sellers, Michael S., Lísal, Martin, Schweigert, Igor, Larentzos, James P., Brennan, John K.
• Format: Conference Proceeding
• Language: English
• Subjects: Accuracy; Coarsening; Computation; Computer simulation; Decomposition reactions; Nitromethane; Organic chemistry; RDX; Reactivity; Simulation; Thermodynamic properties
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.4971502

In discrete particle simulations, when an atomistic model is coarse-grained, a tradeoff is made: a boost in computational speed for a reduction in accuracy. The Dissipative Particle Dynamics (DPD) methods help to recover lost accuracy of the viscous and thermal properties, while giving back a relatively small amount of computational speed. Since its initial development for polymers, one of the most notable extensions of DPD has been the introduction of chemical reactivity, called DPD-RX. In 2007, Maillet, Soulard, and Stoltz introduced implicit chemical reactivity in DPD through the concept of particle reactors and simulated the decomposition of liquid nitromethane. We present an extended and generalized version of the DPD-RX method, and have applied it to solid hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Demonstration simulations of reacting RDX are performed under shock conditions using a recently developed single-site coarse-grain model and a reduced RDX decomposition mechanism. A description of the methods used to simulate RDX and its transition to hot product gases within DPD-RX is presented. Additionally, we discuss several examples of the effect of shock speed and microstructure on the corresponding material chemistry.