Информационная система "Конференции"

Abstracts

MODEL OF DETONATION OF EMULSION EXPLOSIVES

A.E. Medvedev, A.Yu. Reshetnyak, V.M. Fomin

Khristianovich Institute of Theoretical and Applied Mechanics Siberian Branch, Russian Academy of Sciences, Novosibirsk

A mechanism of detonation of emulsion explosives with microballoons in finite-diameter charges is proposed. A parametric dependence of the detonation velocity on the charge characteristics is obtained. The fact that the reaction-zone width increases with increasing charge density is explained. It is shown that complete burnout of emulsion does not occur at the Chapman-Jouguet point. Formulas for the detonation velocity, time, and width of the reaction zone are given.

Emulsion explosives consist of an emulsion binder (ammonium nitrate, water, mineral oil, and emulsifying agent) and a sensitizer. The sensitizer is usually hollow microballoons (glass balls) approximately 100 microns in size (from 20% to 70% (vol.)). Emulsion explosives are widely used in mining industry.

A typical feature of emulsion explosives is a nonmonotonic dependence of the detonation velocity on the charge density (in [1], this is attributed to an increase in the reaction-zone width).

The model of detonation of emulsion explosives developed in [2] is based on two hypotheses: 1) the microballoons are "hot spots" where the emulsion combustion reaction is initiated; 2) emulsion combustion occurs inside the "combustion sphere".

The reaction zone is divided into two parts: 1) zone of microballoon destruction and collapse; 2) zone of burnout in the "combustion sphere". The widths of the two zones, the microballoon collapse time, and the emulsion combustion time are found. The detonation velocity D in the charge of diameter d_mb is determined as a function of the volume fraction m_mb and diameter d_mb of microballoons in the form

D = D(m_mb; tau_0, d_exp, d_mb).

The reaction-zone width is found to be inversely proportional to the cubic root of the charge density. It is shown that complete burnout of emulsion does not occur at the Chapman-Jouguet point. The results obtained are consistent with experimental data.

This work was supported by the grant of the President of the Russian Federation No. NSh-9732.2006.1.

[1] Sil’vestrov V.V. Dependence of detonation velocity on density for high explosives of the second group. Comb., Expl., Shock Waves. 2006. Vol.4 2. No. 4.

[2] Medvedev A.E., Reshetnyak A.Yu., Fomin V.M. Detonation of commercial emulsion explosives. Dependence on the charge diameter. In: XIII International Conference on the Methods of Aerophysical Research, Novosibirsk, Russia, 5-10 February, 2007, Pt I., 123-127.

Note. Abstracts are published in author's edition

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