Environmental Engineering Reference
In-Depth Information
of product adiabatic expansion to cool down to the original temperature of an
explosive, also the theoretical data of the work capacity of an explosive.
The work done by unlimited adiabatic expansion of explosive products until to
absolute zero is the real potential energy of an explosive. But the absolute zero is
nonreachable in real proceedings, and the explosion heat at absolute zero is very
close to that at 15
°
C. So the explosion heat at 15
°
C takes the potential energy of an
explosive.
k
1
T
2
T
1
¼
V
1
V
2
or
k
1
k
T
2
T
1
¼
P
2
P
1
The work done by the adiabatic expansion of detonation products to 1 atm
pressure is expressed in Eq.
2.36
.
"
#
¼ C
v
T
1
1
k
1
k
T
2
T
1
P
2
P
1
A ¼ C
v
T
1
T
2
Þ
¼ C
v
T
1
1
ð
"
#
k
1
k
V
2
V
1
¼ C
v
T
1
1
ð
2
:
36
Þ
If C
v
T
1
is replaced by explosion heat Q
v
, which approximately equals C
v
T
1
, the
Eq.
2.36
becomes
2.37
.
"
#
"
#
k
1
k
k
1
P
2
P
1
V
1
V
2
A
Q
v
1
¼ Q
v
1
¼
g
Q
v
ð
2
:
37
Þ
Here,
ʷ
is the work ef
ciency; P
1
and P
2
are the pressures of initial and
nal
states separately; and V
1
and V
2
are the speci
c volumes of initial and
final state
separately.
Equation
2.37
shows that the real work of detonation products is less than the
potential energy of an explosive. The value of the work is related to the potential
energy of an explosive, the expansion ratio
V
1
V
2
of detonation products, and isentropic
index k.
When the explosion products expand unlimitedly (V
2
is unlimited), the work
done by explosion products equals to the potential of an explosive. If the explosion
heat is higher, the work is more. When the energy potential of an explosive and the
expansion ratio
V
V
2
are
fixed, a larger isentropic index k means the more complete
