Environmental Engineering Reference
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Fig. 2.29 Transportation of pulse waves in the explosion of liquid explosives
the average impact is equivalent to that of spherical charge/packing explosives. If
the charge or packing is obviously larger in one dimension than other dimensions,
the impact within two times of two small dimensions is equivalent to the cylindrical
charge/pack. When it is far away, such several times of the longest charge/packing
dimension, the impact is equivalent to that of spherical charge/packing. This is
because the air shock waves are gradually homogenized in all directions.
The high-temperature and high-pressure detonation products of liquid explosives
expand rapidly. This expansion is regarded as the piston motion in a pipe, which
compresses the surrounding media air and increases its pressure. After the air
detonation waves separate from the detonation products, the detonation waves
transport in the air following what in Fig. 2.29 .
In Fig. 2.29 , t 1 ; t 2 ; ...
are the reaching time of shock waves. Figure 2.29 indi-
cates that the positive pressure area is broadening following the transportation of air
shock waves. Because the shock wave front transports at supersonic velocity D,
while the shock wave end does at sound velocity c 0 ,andD [ c 0 ;
the positive area
broadens, following the transportation of air shock waves. In Fig. 2.29 , the pressure
of wave front and transportation velocity D drop faster. There are several reasons
for the rapid dropping of pressure and transportation velocity. First, the shock
waves expand spheroidally, their surface area of shock wave fronts is continuously
growing, but the energy passing the unit area shock wave fronts decrease. Second,
the average energy of the air shock wave fronts declines. Beside that, when the
shock wave passed the air, the temperature of the air increases, so part of shock
wave energy is used to heat the air. Based on above reasons, in the transportation
process of air shock waves, the pressure of wave fronts declines faster, and decays
into sound wave
finally.
2.4.1.2 Parameter Calculation of Shock Waves Produced by Detonation
of Liquid Explosives in Free Space [ 23 , 24 ]
The detonation products just impact within short ranges, air shock waves create the
main damage of explosion of liquid explosive in free space. The damage and killing
effect of air shock waves are more violent in the closer ranger with smaller impact
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