Predicting the Gurney velocity of chemical high explosives: thermochemical code calculations and studies on the detonation products isentrope

Abstract

ABSTRACT The simplicity and versatility of the Gurney model has led to its widespread adoption for the calculation of peak fragment velocity of explosively-driven munitions such as fragmentation warheads and artillery projectiles. The Chemical Equilibrium with Applications (CEA) thermochemical code provides several relevant parameters that were found to be important for the construction of a mathematical model for estimating the Gurney velocity of pure and mixed chemical high explosives. Compared to other methods, the proposed model demonstrated its accuracy in predicting the Gurney velocity of sensitive and insensitive explosive compositions. Models based on detonation velocity were found to be particularly inadequate to predict the Gurney velocity of insensitive explosives, which is strong proof that the detonation velocity does not necessarily correlate with the Gurney velocity for all types of high explosives. Results from the cylinder expansion test provide some evidence that the low to moderate metal acceleration ability of insensitive explosives is due to their unique and steep expansion isentropes rather than charge diameter effects or non-ideal detonation behavior.