A generalized dependence of the critical detonation diameter of porous substances on the density

A generalized dependence of the detonation diameter of closed-porosity explosives on the relative density is obtained in the form of an $U$-shaped curve. The right branch of the curve can be described within the framework of the theory of V. S. Trofimov. The linear rate of chemical conversion of a substance at an interface is approximately proportional to the pressure. It is shown that despite its purely approximate character, the qualitative theory of Yu. B. Khariton yields the same values of the average reaction rates as the theory of V. S. Trofimov if the coefficient in Khariton’s formula is assumed to be equal to 5. It is noted that in almost all cases the gasification rate of explosives in a detonation wave is greater by a factor of 2–3 than the usual burning rates, which were obtained by extrapolation of the quantities measured in a constant-pressure shell. We propose a mechanism of forced gasification of explosives by a shock-heated gas which fills the pores. The left part of the curve is described under the assumption that the specific combustion surface of low-density explosives is limited by the shock-compression energy supplied to form a heated layer necessary to ignite a detonating substance.