Failure of the Chapman-Jouguet Theory for Liquid and Solid Explosives

Abstract

The usual treatment of unsupported detonation, often called the Chapman-Jouguet theory, is based on four assumptions: (1) the detonation approaches a steady state, (2) the flow is laminar and one-dimensional, (3) the detonation products approach a state of chemical equilibrium some distance behind the detonation front, and (4) the detonation velocity is the minimum permitted by the conservation conditions. Wood and Fickett proposed experiments to test the validity of the Chapman-Jouguet ``theory,'' not requiring knowledge or assumptions about the nature of the equation of state of the detonation products, by making variations of the initial state of the explosive. The results of experiments are reported in which the initial state was varied (1) by using mixtures of nitromethane and another liquid which has the same atomic composition as nitromethane, and (2) by using TNT as liquid and as solid. These results show that the Chapman-Jouguet theory is violated. The calculated pressures are 15 to 20% below the measured pressures. Results of measurements using other explosives are also presented to support the conclusion that the theory fails. No explanation or alternative theory is offered.