Equation of State of Explosive Detonation Products

The equation of state (EOS) of gaseous detonation products is investigated using Ross’s modification of hard-sphere variation theory and the improved one-fluid van der Waals mixture model. The condensed phase of carbon is taken as a mixture of graphite, diamond, graphite-like liquid and diamond-like liquid. For a mixed system of detonation products, the free energy minimization principle is used to calculate the equilibrium compositions of detonation products by solving chemical equilibrium equations. The calculated detonation velocity and pressure of explosive are in good agreement with experimental ones. The equilibrium compositions of detonation products of PETN explosive with different densities at the Chapman-Jouquet (CJ) point are computed and the results are close to those of BKW and LJD EOS. The adiabatic expansion paths from the CJ point is obtained and compared with the results of JWL EOS, it is found that the calculated value of gamma is monotonically decreasing using the presented theory in this paper, while double peaks phenomenon appears using JWL EOS.