The Challenge of Non-Ideal Detonation

Abstract: This paper will compare and contrast detonation in ideal and in highly non-ideal explosives. Ideal explosives, represented here by a TATB / binder system, have relatively flat velocity of detonation (VoD) versus inverse charge diameter relationships, and fail at VoDs only slightly below their ideal CJ values. Highly non-ideal explosives, such as the physically heterogeneous composites used both in Naval and in mining applications, display more complex VoD relationships, and greater deficits at failure. Indeed, the example chosen here of an ANFO / emulsion blend has a bi-linear diameter effect curve, with the VoD at failure being only 30 % of its CJ value. These behaviours are interpreted by examining their reaction rate surfaces (namely the 3D relationship between pressure, extent of reaction and reaction rate). Many of the experimental tests in common use, and many models of the detonation process, rely on particular features of the reaction rate surface that are specific to ideal explosives. Such features are modified or absent from the surfaces for highly non-ideal explosives, with the result that the experimental tests can become either misleading or irrelevant, while the theoretical models are inappropriate. 1