Environmental Engineering Reference
In-Depth Information
q
920
1
1
:
58
=
;
r
0
¼
:
When V
L
¼
920 L
kg
r
L
¼
3
81r
0
;
=
;
:
7r
0
For sphere explosives, the direct effect/impact range of detonation products is
about 10
When V
L
¼
1
000 L
kg
r
L
¼
11
12r
0
For cylinder explosives, the direct effect/impact range is about 30
times of the radius. The detonation products decay very fast in unlimited space, the
effect range for the target is very close.
Because of the inertia, the expansion of detonation products does not stop at
pressure P
0
until it reaches the maximum value of expansion (about 135
-
145V
L
).
Now the average pressure of detonation products is lower than undisturbed air
pressure P
0
. The surrounding air in return compresses the detonation products and
increases their pressure. By the same reason of inertia, the maximum pressure of
products is a little higher than P
0
. The second and multiple expansion-being
compression pulsations occur. The pulsation and whirlpool in the intersurfaces blur
the intersurface, and
-
finally the detonation products and air mix together.
When the detonation products stop expanding and contract back, the air shock
waves separate with the detonation products and propagate independently. For the
detonation of liquid explosives, the separation occurs at about the place, which is
10
20 kg/cm
2
15r
0
. Now the pressure of air shock wave fronts is 10
and the
-
-
propagation velocity is 1,000
1,400 m/s. The mass velocity after fronts is 800
-
-
1,400 m/s. Figure
2.28
gives the pressure distribution of shock waves.
In Fig.
2.28
, the center is the position of liquid explosives. The middle is the
detonation products with median pressure. The most outside is the air shock wave
front, whose pressure is the highest. The pressure of the compression area after the
wave front decays faster. It is sparse area when the pressure is less than 1 atm.
The geometries of packed/charged explosives also impact the air shock waves
differently. If the measurements of packed/charged explosives are very similar in all
directions, the packed/charged geometry impact direction differently in the area,
which is contactable with or very close with explosives. For a little far away places,
Fig. 2.28 Pressure
distributions of pulse waves in
the detonation of liquid
explosives
