R. Meyer J. Köhler A. Homburg Explosives

Thermodynamic Calculation of Decomposition Reactions
322
rocket (half the mass V square root of the velocity); the W Specific
Impulse (mass V velocity) can be calculated according to the following
equation (the same as shown on p. 293):
Is = öäääääää 2J (Hc–He) Newton seconds per kilogramm
or
Isfroz = 92.507 öääää Hc–He
J: mechanical heat equivalent
unit:
Isfroz: specific impulse for frozen equilibrium Ns/kg
Hc: enthalpy of the burnt gases in the chamber kcal/kg
He: enthalpy of the gases at the nozzle exit kcal/kg
Tc: gas temperature in the chamber K
Te: gas temperature at the nozzle
exit with frozen equilibrium K
The computer program also allows calculations for shifting (not frozen)
equilibria by stepwise iteration operations.
The following parameters can also be calculated with computer facilities:
chamber temperature (adiabatic flame temperature);
temperature of exit gas with frozen equilibrium;
composition of exit gas with shifting equilibrium;
temperature of the burnt gases in the chamber and at
the nozzle exit;
average molecular weight, of the burnt gases in the
chamber and at the nozzle exit;
total mole number of the burnt gases in the chamber
and at the nozzle exit;
specific impulse at frozen and with shifting equilibrium;
ratio of specific heats cp/cv;
An example for the calculation of a double bases rocket propellant:
Composition:
nitrocellulose 52.15% (13.25% N)
nitroglycerine 43.54%
diethylphthalate 3.29%
Centralit I 1.02%
sum formula for 1 kg propellant: C19.25H25.96O36.99N10.76
chamber pressure: 7.0 MPa (1015 p.s.i.)