Environmental Engineering Reference
In-Depth Information
There is steady detonation and unsteady detonation. The steady detonation has
constant propagation velocity/rate; while the unsteady detonation has changing
propagation velocity/rate. Generally, all detonation is steady detonation, and
unsteady detonation is explosion.
When the toner initiates the detonation, in its
first stage, detonation rate varies
and increases gradually. This stage is unsteady detonation. Detonation experiences
unsteady acceleration period and reaches the maximum steady velocity/rate/speed,
and this maximum velocity is maintained until all explosives react completely.
Until now, there is little report for the study of chemical reaction zone in the
detonation wave fronts of liquid explosive explosion. For a long time, the deto-
nation mechanism of liquid explosives is considered to follow the one-dimensional
model of Zeldovich, the same detonation mechanism as that of gas explosive.
Although this assumption is accepted, and gets some approvement by the calcu-
lation of condensed media impact heating, the calculation and approvement are just
one-sided and super
cial. The detonation of liquid explosives is different from that
of condensed explosives. Detonation growth process of liquid explosives is a
process of weak detonation to strong detonation, from unsteady combustion/
burning to steady combustion/burning,
finally to detonation. Only the development
of techniques and renewal of equipment help prove and clear below issues: the
chemical reactions and dynamics of complex organic molecules under high pres-
sure, the change of state function in energy releasing processes, the rule analysis of
condensed medium expansion, distribution, and calculation of elastic energy and
heat from chemical energy, work contribution of explosion methods and produced
pressure platforms, numerical simulation of liquid explosive detonation, etc. Only
after the differences from condensed explosives are settled down, the pressure
pro
le of chemical reaction zone in the explosion of liquid explosives can be
explained or calculated.
In the past, it is believed that the detonation of an explosive only has over-
compressed detonation, and normal detonation, or DTT detonation from self-sus-
taining spread combustion/burning to detonation. Although there are detonation
phenomena, which are not normally explained, only CJ detonation and its features
gained the attention. Other kind of detonation is seldom being referred. If proper
ignition method is used, most detonation can be transited into under-compressed
detonation.
“
Under compressed detonation
”
is corresponding to the
“
over com-
pressed detonation state
”
. Earlier it was also named
“
weak detonation
”
[
4
,
5
].
uence than that
of condensed explosives with the same mass and especially in closed or semiclosed
space, we started to investigate the characteristics of self-sustaining detonation of
liquid explosives, as well as the underlying detonation mechanisms.
Because shock waves from liquid explosives have a stronger in
fl
2.2.2.1 Detonation Mechanisms of Liquid Explosives
In the overpressure detonation, Rayleigh line represents the line of momentum and
mass conservations; Hugoniot curve represents the curves of energy conservation.
