V. V. Sil’vestrov

Effect of the density of an emulsion explosive on the reaction zone width

This paper presents experimental dependences of the width of the reaction zone and detonation critical diameter on the initial density with a variation in the density of an emulsion high explosive from 0.5 to 1.33 g/cm3. Glass microballoons were used as a sensitizer. The emulsion explosive is characterized by an U-shaped dependence of the critical diameter on the density, and the reaction time and the width the reaction zone increase monotonically with the density of the explosive. The detonation pressure of the studied compositions varies in the range of 0.6–12 GPa.

Shock compression of an emulsion matrix at pressures up to 37 GPa

This paper presents an experimental study of the shock compression of an emulsion matrix based on an aqueous solution of ammonium and sodium nitrates at pressures up to 37 GPa, which is significantly higher than the calculated detonation pressure. The data obtained were used to determine the parameters of the Hayes equation of state and calculate the shock heating temperature of the matrix. At a pressure of more than 17 GPa, the input pressure profiles shows a rise associated with the chemical transformation of the emulsion.

Electrical conduction of emulsion explosives

Results of experiments to obtain a spatial distribution of electrical conduction of emulsion explosives for different content of a sensitizer are presented.

The development of the aluminum sulfide synthesis reaction on explosive loading of a cylindrical ampoule

In the scientific literature, much attention is paid to investigation of phase transitions on explosive load� ing, in particular, solidphase chemical transforma� tions under the action of shock waves. However, such transformations are studied mostly experimentally (1, 2), and their mathematical models are virtually unavailable. It is natural because chemical transfor� mations are difficult to study in the course of explosive loading and reliable data on the dynamics of these phenomena are not always easy to obtain from experi� mental results. Meanwhile, novel promising materials are more and more often produced and used in fast processes at high strain rates, pressures, and temperatures. These processes are accompanied by structural changes and sometimes chemical reactions. The currently widely used explosive technologies in metal working are most developed in forming, welding, cutting, hardening, and sealing, and many of these technologies have already been commercialized. At the same time, the effect of shock waves on solidphase reactions is still insufficiently studied and, by the present time, has not yet reached a technology level because of the lack of experimental data and also mathematical models that could take into account both the coupling of mechan� ical and physicochemical processes, including their combined action, and the effect of each factor. The purpose of this work was to experimentally and numerically study the dynamics of development of aluminum sulfide synthesis on explosive loading of a cylindrical ampoule on the basis of a phenomenologi� cal model of chemical transformations. In this work, we proposed a new approach to numerical analysis of solidphase synthesis processes on explosive and shockwave loading on the basis of a developed mathematical model of a multicomponent medium. The time dependence of the pressure of the explosion products was described based on qualitative and quantitative agreement of the results of experi� mentally and theoretically determining the parame� ters of explosive loading of a cylindrical ampoule. The conditions were found for the transition from partial to complete conversion in the synthesis reaction in the shock front on reflection of the shock wave from the bottom cap of the ampoule. It was experimentally and theoretically established that, once the reaction in the shock wave is fully completed, the ampoule is broken down because of the formation of a gas phase and an increase in pressure, with the breakdown being initi� ated in the bottom part of the ampoule.

Protective properties of shields of ceramic/aluminum composite for hypervelocity impact

The protective effect of thin shields of metal-composites based on a matrix of aluminum with dispersed inclusions of SiO2 and Al2O3 for hypervelocity impact of spherical steel particles are examined in a one-layer protection scheme. The protective effect of shields of these materials are found to be inferior to shields of homogeneous aluminum alloy.

Acceleration of solid particles during cumulation of detonation products in vacuum

The possibility of increasing the velocity of solid particles accelerated by an explosion of a long tubular charge of a high explosive (HE) in vacuum is analyzed. The experimental results obtained indicate that the acceleration velocity cannot be considerably increased. The probable causes are erosion of the material from the inner surface of the HE tube and a significant decrease in the mass flow velocity when the length of the HE tube exceeds the optimum length.

New applications of emulsion explosives

This paper considers the use of emulsion explosive compositions to join building bars and replace worn thread in the railway wheel axle. The compositions do not contain individual explosives and greatly increase the safety in explosive working of metals.

Temperature measurements of a shock-compressed emulsion matrix

The temperature of a shock-compressed invert emulsion based on an aqueous solution of ammonium and sodium nitrates was measured using two experimental techniques: using planar thermocouples at pressures of 3.4–12.0 GPa and optical pyrometry at pressures of 9–22 GPa. The experimental data obtained using the thermocouple method are consistent with the calculated values. The optical measurement results are significantly higher than the calculated data and indicate the presence of a spatially inhomogeneous temperature field behind the shock front in the emulsion due to the structural inhomogeneity of the medium.

Evolution of electrical conductivity of emulsion explosives during their detonation conversion

Electrical conductivity of explosion products behind the detonation front of emulsion explosives is measured. The composition of the emulsion matrix and the amount of the additive consisting of sensitizing glass microspheres are varied. The peak value of electrical conductivity for the examined compositions is 0.5–0.05 Ω-1 · cm-1.

Influence of artificial pores on the detonation parameters of an emulsion explosive

This paper presents the results of a study of the influence of the characteristics of porous inclusions on the detonation parameters of emulsion explosives (EMX). Glass and polymeric microballoons, perlite grains, hollow cenospheres, and a gas-generating additive are used as sensitizers. It is shown that polymeric microballoons with an ultra-thin wall filled with isobutane are the most efficient sensitizer that allows the potential of EMX to be fully realized.