2018 Physics/Theoretical Colloquium
 
Thursday, August 23rd , 2018
3:45 – 4:45 p.m.
Rosen Auditorium (TA-53, Bldg. 1)
Refreshments at 3:15pm
 
Speaker:   Dr. Scott Jackson
 
M-9: SHOCK AND DETONATION PHYSICS
Los Alamos National laboratory
 
“Condensed Phase Detonation: Are Meaoscale Effects Needed to Predict Performance?”
 
Abstract: 
 
Condensed-phase explosives provide one of the most high-power and energy-dense storage materials available. They are commonly detonated to perform work on adjacent materials for engineering applications in the defense and mining industries, with several billion kilograms used in the United States alone per year.  Explosives will detonate when processed by a sufficiently strong shock wave, producing product energy densities approaching 14 MJ/L and energy release rates exceeding the radiative flux at the solar surface. Conditions in the detonation reaction zone are at the upper limit of the the condensed matter regime.  Despite their engineering utility and broad use, very little is known about the detonation reaction-zone physics due to the extreme conditions that are generated.  An additional complication is that most practical explosives contain a heterogenous microstructure consisting of a composite matrix of chemically complex energetic crystals and inert binding materials.  This feature is thought to induce highly localized chemical and thermodynamic variations at the mesoscale during shock passage.

This talk reviews the chemistry and microstructure of high explosives, discusses the mesoscale effects present at scales on the order of the reaction zone thickness during detonation, and considers if resolving these mesoscale effects is critical to the prediction of detonation performance for these materials.  A  universal detonation product equation of state is also derived from several newly discovered empirical correlations.  This new result implies the product energy density scales with reactant kinetic energy density, which is the product of the explosive initial density and detonation velocity squared, for all condensed-phase energetic materials and that explosive microstructural or chemical details only influence the product energy density though these two parameters.