Post-detonation fireball modeling: Validation of freeze out approximations

A numerical simulation study was performed to examine the post-detonation reaction processes produced by detonation of a 12 mm diameter hemispherical pentaerythritol tetranitrate (PETN) explosive charge. The simulations used finite rate detailed chemical model consisting 59 species and 368 reactions capture including air dissociation from Mach 19+ shock waves that initially break out PETN charge, within products during expansion, afterburning when mix with heated air. multi-species thermodynamically complete Becker–Kistiakowsky–Wilson real-gas equation state is for gaseous phase allow mixing reactive species. recent simplified burn propagate through charge processes. computed blast, structures, mole fractions agree well experimental measurements. comparison results equilibrium calculations indicates assumption local fairly accurate until rapidly cool temperatures in range 1500–1900 K expansion waves. Below this range, show are nearly chemically frozen significant portion expansion. These consistent freeze approximation blast modeling community.