R. Meyer J. Köhler A. Homburg Explosives

Thermodynamic Calculation of Decomposition Reactions
are taken into consideration (high caloric gunpowders; rocket propellants).
In the computer operation, the unknown mole numbers are varied by
stepwise “iteration” calculations, until all equation conditions are satisfied.
The following results are obtained.
heat of explosion
temperature of explosion
average molecular weight of the gaseous explosion
products
total mole number
specific energy (force)
composition of the explosion gases
specific heat ratio cp/cv
covolume
etc.
The basis data for internal ballistic calculations are thus obtained (also
W Ballistic Bomb; W Burning Rate). As an example for the calculation
of a double base gunpowder*):
composition
nitrocellulose (13.25% N): 57.23%
nitroglycerine: 40.04%
potassium nitrate: 1.49%
Centralite I: 0.74%
ethanol (solvent rest): 0.50%
Enthalpy of formation of the composition: –2149.6 kJ/kg = –513.8
kcal/kg
The results (loading density assumed: 210 kg/m3 )
sum formula for
1 kg powder:
C18.14H24.88O37.41N10.91K0.015
temperature of explosion: 3841 K
pressure: 305.9 MPa =
3059 bar
average molecular weight of
gases: 27.28 g/mol
total mole number: 36.66 mol/kg
specific energy (force): 1.17V106 Nm/kg =
1170 kJ/kg
kappa k = cp/cv): 1.210
covolume: 9.37V10 –4 m3 /kg
* Calculated by the ICT-Fortran programm.
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