Dependence of the time-space structure of the chemical-reaction zone on the initial density of the explosive

The results of a study of the chemical-reaction zone structure for a number of high explosives (HEs) are discussed. It is found that an increase in the initial density of the HEs leads to a structural change in the chemical-reaction zone involving elimination of the Von Neumann spike at the critical density point. Conversely, as the initial density of the explosive decreases, the ratios of the gas-dynamic parameters (in particular, mass velocities) at the Von Neumann point to the same parameters at the Jouguet point increase. It is shown that to explain the indicated regularities, one does not need to invoke the assumption of an increasing contribution of the exothermic decomposition of the HE the shock. The results can be explained within the framework of classical Zeldovich–Von Neumann–Düring theory with an ordinary shock at the detonation-wave front and, hence, with a nearly zero contribution to the total energy release in the chemical reaction zone.