Fluid Mechanics of Deflagration-to-Detonation Transition in Porous Explosives and Propellants

Abstract

The fluid mechanical processes which characterize a transition from deflagration to detonation in granular beds of solid propellant have not at present been sufficiently refined to allow accurate modeling of the phenomenon. In an attempt to improve this situation, this paper reports on the investigation of the basic mechanisms and consequences that arise from a set of assumptions for the governing and constitutive equations which take into account the two-phase nature of this problem. A qualitative description of the flow process is made, based on observations obtained from deflagration-to-detonation transition (DDT) experiments. From this, certain conclusions are reached as to the properties needed by propellants to exhibit a deflagration-todetonation transition. The numerical integration scheme itself is examined in detail in order to further understand the consequences of its use. Also, two scenarios for DDT are presented which exhibit characteristics similar to those derived from experimental evidence. Conclusions as to the direction of future research are made based on the results obtained from the work which led to these two basic mechanisms for DDT.

An approach formulated in terms of conserved variables for the characterisation of propellant combustion in internal ballistics

“…The combustion process in gas–solid particle mixtures has raised the interest of many researchers in the last few decades. This is due to the major importance of the two‐phase flow problem in many different industrial fields, such as heat or power generation , propulsion , fire propagation , hazard explosions , prevention of detonations or, finally, the analysis and design of pyrotechnic and ballistic devices . In the particular case of internal ballistics, the use of computational methods has broadly extended in recent years.…”