The deflagration-to-detonation transition (DDT) in high density pentaerythritol tetranitrate (PETN)

Abstract

The deflagration-to-detonation transition (DDT) is a mechanism by which explosives can transit from burning to detonating under suitable confinement and powder morphology conditions. The length that this transition is able to occur for specific explosives is an important safety consideration. The DDT length in Pentaerythritol Tetranitrate (PETN) has been studied extensively previously as PETN is a common explosive used in detonators. DDT has been observed to occur in PETN on length scales on the order of tens of millimeters for densities up to 1.56 g/cc, which is roughly 88% of its theoretical maximum density (TMD; for PETN: 1.778 g/cc). However, standalone pellets of pressed PETN commonly exceed 90% TMD. The DDT length versus density curve for PETN appears to approach an asymptote past 88% TMD, and so previous work cannot answer definitively whether or not higher-density PETN pellets will undergo DDT nor what run length is required for the transition. In this work, we explore the DDT reaction in 1.65 g/cc PETN (93% TMD). Our results for DDT run length in low density PETN are in good agreement with previous studies; however, we found that PETN pressed to 93% TMD did not undergo DDT for run lengths less than 150 mm.