R. Meyer J. Köhler A. Homburg Explosives

317 Thermodynamic Calculation of Decomposition Reactions
1.4 Specific energy.
The concept of specific energy can be explained as follows. When we
imagine the reaction of an explosive to proceed without volume expansion
and without heat evolution, it is possible to calculate a theoretical
thermodynamic value of the pressure, which is different from the
shock wave pressure (W Detonation); if this pressure is now multiplied
by the volume of the explosive, we obtain an energy value, the “specific
energy”, which is the best theoretically calculable parameter for
the comparison of the W Strengths of explosives. This value for explosives
is conventionally given in meter-tons per kg.
The specific energy results from the equation
f= nRTex.
f: specific energy
n: number of gaseous moles
Tex: detonation temperature in degrees Kelvin
R: universal gas constant (for ideal gases).
If f is wanted in meter-ton units, R*) has the value 8.478 V 10 –4 .
The values for the considered example composition are
n = 38.19
Tex = 3670 K
f = 38.19V8.478V10 –4 3670 = 118.8 mt/kg.
For the significance of specific energy as a performance value,
W Strength.
1.5 Energy level.
Because higher loading densities involve higher energy concentration,
the concept “energy level” was created; it means the specific energy
per unit volume instead of unit weight. The energy level is
l=r·f
l: energy level mt/l
r: density in g/cm3 f: specific energy mt/kg.
Since the example composition will have a gelatinous consistency, p
may be assumed as 1.5 g/cm3 . The energy level is then
l = 1.5V118.8 = 178.2 mt/l.
1.6 Oxygen balance.
W oxygen balance
* For the values of R in different dimensions, see the conversion tables on the
back fly leaf.