engleski

Numerical modeling of thermal initiation of explosives

During their production, handling, and use, explosives and munitions can be exposed to a variety of unplanned thermal stimuli. Heat energy absorbed from surrounding heat source leads to exo-thermic chemical decomposition of an explosive and can, under certain conditions, result in so-called thermal explosion. Because possibilities of such events are of great concern among explo-sive’s community, many theoretical, experimental, and simulation studies have been done in the past few decades exploring the thermal initiation phenomenon. Attempts are directed towards development of reliable numerical models capable of predicting response of explosives to thermal stimuli. Such predictive tools will enable reduction of costs associated with necessary testing and will give additional insight into the thermal behaviour of energetic materials. In this paper we present in-house one-dimensional reactive heat transfer code aimed to model various thermal insult scenarios associated with explosives. The code predicts the transient temperature distribution, the time to ignition, and the location of ignition. The code uses the finite difference method and has built-in self-adjustable time step, various reaction rate models (single-step and multi-steps), and composition- and temperature-dependent thermophysical properties. The results of calculation are compared with literature reported experimental data on cylin-drical nitrocellulose specimen and spherical specimens (One-Dimensional Time to Explosion, ODTX, test) for several explosives. Special attention is given to analysing the effect of reaction kinetics on calculation results.

explosives; thermal initiation; cook-off; finite difference method; reactive heat conduction; energy balance equation; numerical modelling

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