Environmental Engineering Reference
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Fig. 2.4 Schematics of combustion and detonation. 1 Liquid explosives; 2 exchange zone of
chemical reactions; 3 change front width of chemical reactions; D spread speed of fronts in liquid
explosives
The passing distance of burning within the time period from ignition to detonation
of explosives is detonation front. Under different conditions, the detonation front
and degree of dif
culty from burning to detonation are various.
In the combustion, detonation materials on the chemical exchange fronts shift
along the media. These processing chemical exchange fronts are detonation fronts.
The explosive materials react to products within the front ranges. In general, det-
onation is a phenomenium of fast self-spreading of detonation wave along the
explosives. The spreading speed is less affected by environment. The pressure near
the explosion point rises dramatically. Whether explosion is in the closed container
or not, the products of explosion impact the around media drastically, then break
and deform the staff around. The schematics of detonation is shown in Fig. 2.4 .
The mechanisms of combustion and detonation are different. In burning, the
chemical exchange fronts spread slower than the sound in liquid explosives. But in
the detonation, the chemical exchange fronts shift faster than the sound in liquid
explosives. Burning is spread through heat conduction, diffusion, and radiation
inside the explosives. But detonation is through shock waves. Detonation waves are
the shock waves following the fast chemical reactions.
These two forms of explosion of liquid explosives can interchange with each
other. In certain case, combustion may transform into unstable detonation and
further evolute into stable detonation.
2.2.2 Detonation of Liquid Explosives
Detonation is a process in which chemical changes occur inside explosives or
fl
flammable mixtures, whose process has some similarity with combustion. The
feature of detonation is that chemical reactions do not occur within the materials at
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