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

Abstract

Peculiarities of solid-phase synthesis are experimentally and numerically investigated in the aluminum-sulfur and aluminum-teflon mixtures placed in cylindrical ampoules under explosive loading. In the experiments, the parameters of explosive loading are chosen close to those that are commonly used for explosive compaction of inert porous fillers in cylindrical ampoules. The experimental results show that cylindrical ampoules are damaged when a mixture capable of ultrafast exothermic reactions is used as filler under explosive loading. To find the reasons of ampoule damage, the numerical computations are carried out by the finite element method based on the model of a multicomponent medium. The synthesis reaction in the mixture is described using the phenomenological model of irreversible chemical reactions based on zero-order kinetics. Simulation of porous mixture compaction is carried out using the kinetic model of the active type, which determines the growth or collapse of pores continually changing the material properties and causing stress relaxation. The sharp increase in pressure is found in the bottom part of the ampoule after reflection of the shock wave from the bottom lid of the ampoule in the form of a compression wave, which is accompanied by increasing the rate of chemical reactions. The high rate of heat release during chemical reactions in the bottom part of the ampoule leads to the formation of gas phase, which leads to further increase in pressure and fracture of the ampoule.