This study investigated the formulation and characterisation of emulsion
explosives. This included the manufacture of more than 120kg of emulsion
explosive of which around 105kg was used on the explosive ordnance range in
over 350 individual firings. For each emulsion composition, an average of eight
firings was undertaken with which to substantiate the explosive performance data.
The formulation was varied to determine the effects of water content upon the
physical characteristics of the emulsion. These physical effects included thermal
conductivity, particle size, viscosity and the explosive performance of the
emulsion. In respect of explosive performance, microballoons were added to
sensitise the emulsion and the proportions of microballoons added were altered to
look at their effect on velocity of detonation, sensitivity and the brisance of the
emulsions.
Emulsion explosives are commonly referred, in literature, as Type 11 non-ideal
explosives. This is due to their non-linear behaviour with respect to the variation
of velocity of detonation with density. Traditionally, when an emulsion explosive
was commercially manufactured, the water content has been kept at a minimum
(12-17%). This was accepted as the way to achieve the best explosive
performance, based upon the belief that an emulsion with the highest
concentration of active ingredients, ammonium nitrate and oil, would give the best
explosive performance.
This study examined a wider range of emulsion explosive water contents than has
been previously studied, from 12% to 35% water. It was found, during this study,
that higher water content emulsions, specifically 25% water, had a marked
increase in explosive performance. The highest velocity of detonation recorded
was in a 39mm diameter tube, at 25% water content with 3% microballoons, was
5558ms-1. This was some 15% higher than any other VOD recorded in this study.
The high velocity of detonation, at 25% water content, was one of a number of
physical characteristics in which this water content varied from the other emulsion
water contents. This study endeavored to show that emulsion explosives could exhibit two differing
types of explosive reaction, thermal explosion and grain burning. This was based
on the velocity of detonation and plate dent data, both of which indicated that there
was a change in reaction with water content. Emulsion explosives, with a high
water and high microballoon content, exhibited a thermal explosion type reaction.
They exhibited Type I ideal explosive behaviour, with increasing velocity of
detonation with density. Lower water content emulsion explosives, displayed the
more commonly expected Type 11 non-ideal behaviour and reacted in a grain
burning type detonation.
| Identifer | oai:union.ndltd.org:CRANFIELD1/oai:dspace.lib.cranfield.ac.uk:1826/3976 |
| Date | 17 November 2009 |
| Creators | Allum, J |
| Contributors | Cartwright, M |
| Source Sets | CRANFIELD1 |
| Language | English |
| Detected Language | English |
| Type | Thesis or dissertation, Doctoral, PhD |
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