Environmental Engineering Reference
In-Depth Information
2.2.1 Combustion of Liquid Explosives
Combustion reaction of explosives is de
fl
agration, which is another classic form.
De
agration is different from general combustion. Explosives have oxidants and
combustible materials. Combustion of explosives does not need the oxygen in air,
and it spreads smoothly. For propellants and pyrotechnics, combustion is the basic
form of explosion. Some primary explosives work through combustion or com-
bustion
-
detonation. Here in all, study of the general rules of liquid explosives and
the basic conditions of combustion-to-detonation are of great importance for the
safety productions and applications of liquid explosives.
fl
2.2.1.1 General Features of Combustion of Liquid Explosives
Combustion is very common, e.g., combustion of wood, coal, etc. The chemical
reactions with light and heat released are combustion. The space with light and high
temperature of chemical reaction is named as
flame. The geometric surface of
separating burning layer from nonreaction zone is the
fl
flame front.
The combustion of liquid explosives leads to violent chemical reactions, which
spread themselves. It is different from the combustion of general fuels. The com-
bustion of liquid explosives can be isolated from air, and the oxidations depend on
the oxygen of the explosive. This combustion is also de
fl
fl
agration. The processes of
explosive combustion are the processes in which
fl
flame fronts spread themselves
[
1
]. Spreading of
flames is determined mainly by conduction of heat and diffusion
of combustion productions [
2
].
Combustion of liquid explosives is different from that of condensed ones. Liquid
explosives are noncompressible, and have
fl
fixed density, and their combustion
spreading is continuous and fast. There are two stages for the combustion process of
liquid explosives. First, the surfaces of liquid explosives
ame
spreads into the inside of the liquid explosives. The burning reaction spreads along
the interface of liquid explosives and air is surface combustion, while the burning
reaction spreads along the normal directions is section combustion. Starting of
liquid explosive combustion has two ways: spontaneous ignition and forced igni-
tion. Spontaneous ignition is produced through the self-acceleration of chemical
reactions of liquids. Forced ignition is reached by external heat source at high
temperature. Forced ignition is common in the application of liquid explosives. To
ignite the liquid explosives,
fl
ame. Then, the
fl
fire source should have enough high temperature and
enough heat to supply.
Burning speed is an important parameter of combustion. There are two ways to
show the burning speed: linear speed of
flame front spreading and mass speed of
combusted liquids. The linear speed (u)of
fl
fl
flame front spreading along the liquid
