Destruction of cylindrical ampoules containing solid phase reaction mixtures under explosive loading

Abstract

Peculiarities of solid-phase synthesis in aluminum-sulfur and aluminum-fluoroplast mixtures in cylinder ampoules under explosive loading have been studied in experiments and numerically. In experiments the chosen parameters of explosive loading were similar to those which are usually used for explosive compacting of the inert porous materials in cylinder ampoules. The results of experiments show that cylinder ampoules are destructed in explosive loading conditions when mixture used as a filler is capable of very fast exothermal reactions. To find out the reasons of ampoules destruction numeric calculations have been carried out by the method of finite elements on the base of multicomponent media. While studying the deformation of multicomponent media it is necessary to take into account the state and reaction of each component and components displacement inside a chosen released volume of the mixture. As a condition of compatible deformation of the components a pressure balance of mixture components was chosen. Synthesis reaction in the mixture was described by the phenomenological model of irreversible chemical transformations based on zero-order kinetics. Simulation of compaction of the porous mixture was carried out on the base of a kinetic model of active type, which describes the growth or collapse of the pores resulting in a permanent change of the material properties and stress relaxation. It was found that pressure is increased sharply at the bottom of the ampoule when shock wave is reflected from the bottom ampoule lid as a compressive wave which is followed by chemical transformation rate growth. High rate of heat release during reaction in a lower ampoule part resulted in gas phase formation which leads to a further pressure increase and becomes the reason of ampoules destruction.

Effect of Explosive Processing on the Structure and Properties of Polyarylate

“…A promising way of obtaining products from powders of hard-to-process polymers is explosive processing (EP) [10][11][12][13][14]. The explosive impact simultaneously implements high pressure, loading rate and temperature, which creates favorable conditions for structural transformations and largely determines the properties of the resulting materials [13][14][15][16][17][18][19][20]. In this work we present the results of the study of the effect of the method of obtaining compacts on changes in the structure and properties of polyarylate.…”