Thermochemical release mechanisms and circumferential initiation affecting detonation in an aluminized explosive

A modified thermochemical energy term and γ-law extension are incorporated into the JWL equation of state for predicting PBXN-111 detonation behavior under self- and externally supported conditions. The modifications resolve previous speculations regarding the causes affecting non-scalability of the reaction zone and detonation velocity with respect to explosive diameter, and a problem encountered to quantify increased detonation power gain by circumferential initiation. The modifications accurately consider “static effects” of size and the additional hydrodynamic compression resulting from a consecutive 2-step shock jump during convergent front collapse, leading to an elevated von Neumann spike and Chapman-Jouguet state between which physical and chemical transformations take place affecting shock regeneration and detonation power release. Necessary modifications to the CYLEX test are recommended to ensure that wall expansions are measured under steady-state conditions.