Environmental Engineering Reference
In-Depth Information
clearly indicated that the transition process from combustion to detonation for the
gas/solid/liquid three-phase mixture mainly involves reaction compression process,
transition process, reaction shock process, and detonation process.
7.1.1.5 Explosion Characteristic of the Mixture of Nitromethane
and Other Explosives
Aside from the sensitizers described above, nitrate and ammonium nitrate can also
be employed as explosive sensitizer for nitromethane. In addition, adding metal
powder (e.g., Al powder) into nitromethane can increase the corresponding
explosion energy and detonation sensitivity. To prevent potential separation of solid
components, nitrocellulose or cellulose acetate may be used as thickener [
40
,
41
].
Nitromethane itself is a liquid explosive, and the mixture of nitromethane with
nitroglycerin, ethylene glycol dinitrate, as well as other nitrate esters are also novel
liquid explosives. In addition, nitromethane can dissolve nitrate salts such as
sodium nitrate and potassium nitrate, aromatic nitro compounds such as TNT and
nitro naphthalene, and the liquid explosive mixture of RDX and HMX, which can
effectively decrease the critical diameter until it is extremely small. Generally, small
critical diameter is bene
cial for well sinking process because the explosion
properties are not confined by any factor under these circumstances. When nitro-
methane is used as the liquid wax component for nitro explosives, the critical
diameter of explosive liquid can be decreased to 1/64. Therefore, carefully selecting
a liquid explosive composition can minimize the production and perseverance of
nitrogen dioxide at high temperature. When it is in use, one can properly adjust the
pump speed to make sure that explosives are poured into the borehole to obtain a
continuous
fl
flow while preventing the occurrence of autogenous ignition due to
friction [
42
].
The large-caliber weapon system Laboratory of US Army Ordnance Research
and development board [
1
] evaluated
five kinds of explosives for the purpose of
mining single bunker, and they recommended three nitromethane-containing liquid
explosive mixtures. The compositions were shown in Table
7.11
.
Depending on technical requirements, explosives that can be used for individual
bunkers must meet two important criteria: (I) at
C, the explosive should still
have excellent charge properties with decent mobility, plus, it should be easy to
handle; (II) the explosive should be able to work well, easy to detonate and transmit
40
°
−
Table 7.11 Composition of nitroalkane explosive mixtures [
1
]
Consistency
75 nitrometh-
ane/25
nitroethane
RDX
Aluminum
(type 3 or
7)
Nitrocellulose
(N 12.5 %)
Cab-O-Sil
(M5)
Level E Level A
Liquid
59.5
30
10
0.5
-
-
Slurry
48
30
20
2
-
-
Creamy
24
15
60
-
1
-
