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Optimization of Wall Velocity Measurements Using Photonic Doppler Velocimetry (PDV)

Künzel M., Němec O., Pachman J.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 1

89--97

EN

The paper describes the measurement of cylindrical charge wall velocity profiles at various angles to the surface normal. The wall velocities were measured using simple zero generation photonic Doppler velocimetry (PDV). The detonation velocity was measured simultaneously using fiber optic probes coupled with a digital chronometer. The PDV probe angles were set in the range of -2° to 17° to the surface normal. Powdered pentaerythritol tetranitrate (PETN) and the PETN-based plastic-bonded explosive Semtex 1A were selected as the explosive materials in order to ensure reliable detonation under the measurement conditions. The explosive charges were confined in thin-walled aluminum tubes with an internal diameter of 16 mm and wall thickness of 2 mm. The results can be useful for the characterization of charge expansion phenomena and also for the optimization of cylinder test measurements using PDV. Gurney constants were determined for both explosives.

2

Erythritol tetranitrate as a sensitizer in ammonium nitrate based explosives

Künzel M., Němec O., Matyáš R.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 3

351--358

EN

This paper focuses on ammonium nitrate based explosives sensitized with erythritol tetranitrate. Erythritol tetranitrate (ETN) is an ester of nitric acid and erythritol. It is a low melting crystalline solid with explosive properties similar to those of pentaerythritol tetranitrate. Experiments were conducted in order to determine any sensitizing effect this compound might have on three basic types of ammonium nitrate based mixtures – powdered, slurry and emulsion explosives. According to the results obtained, erythritol tetranitrate acts as a sensitizer giving detonator sensitivity to ammonium nitrate based explosives when incorporated therein in quantities from 10 to 20 percent.

3

Fortifcation of W/O Emulsions by Demilitarized Explosives. Part I. Use of TNT

Němec O., Jungová M., Mareček R., Novotný M., Zeman S., Šelešovský J.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 3

193-207

EN

This paper presents a study of the relationship between detonation velocities, D, and relative explosive strength (RS) of fortifed W/O emulsion explosives, on the one hand, and the grain size and quality of the demilitarized TNT used for this fortifcation, on the other. It has been found that demilitarized TNT having a grain size below 400 μm could give acceptable results both in terms of initiation and detonation velocity and the RS values. Demilitarized TNT, however, is not a reliable sensitizer even in a micronized state, and therefore using TNT necessitates simultaneous sensitizing of the fnal W/O explosive with microballoons and it has no signifcantly better infuence on the performance of the resulting explosives. The small-scale cook-off test of such a W/O mixture fortifed by 50% by wt. of TNT has shown that such a mixture is a relatively safe explosive.