3-Component reactive flow modeling of Nitromethane

We present a 3-component reactive flow model for nitromethane (NM) as an improvement upon the 2-component global chemical reaction kinetics to describe the detonation reaction zone behind the shock front. A 2-component model, in this case, is the representation of unreacted raw explosive transitioning to final products using a single reaction progress variable. The groundwork of the approach was laid out in a previous publication ( Stewart, J. Appl. Phys. 2016), but implementation of the model was never formalized. Molecular dynamics experiments and simulations on nitromethane from that of Blais et al(J. Phys Chem, 1997) and the Goddard group (J. Phys Chem, 2011) agree that an unstable heavy condensate is created shortly after shock passage which then decomposes exothermically into final products. Where a 2-component model can only add energy to the flow as reactants decompose, a 3-component model with an included endothermic reaction step can both add and subtract energy, depending upon the component mass fraction gradients. With the addition of an intermediate component, we intend to show a more proper understanding of phenomena such as the shock initiation of nitromethane. Modern gas gun experiments that propel a right circular disk impactor, and laser-ablation-product launched flyer experiments (Dlott, AIP Confer. Proc., 2015) have been used extensively on nitromethane. We intend to use this data set to compare our 3-component reactive flow model and 2-component models for accuracy and validity of shock initiation prediction.