It is well known that the detonation velocity for condensed-phase high energetic materials depends on the initial state, i.e., temperature and density. At present time, for the numerical simulations of the detonation physics, the parameter set of the equation of state (EOS) for the detonation products has to be prepared for each initial condition. However, if the complete reaction is assumed, the state surface has to be unique. We therefore have proposed the unified form EOS for detonation products. In this paper, the relationship between the initial temperature dependence of the detonation velocity and the initial density is examined using a proposed unified form of the EOS. The derivatives of the variables at Chapman-Jouguet (C-J) points are calculated by the unified form of the EOS. These derivatives are used to investigate the initial state dependence of the detonation velocity using the relationship between the detonation velocity and the initial state variables. As a result, the contributions of the coefficient of thermal expansion and the increment of the initial internal energy to the detonation velocity are clarified. We found that the initial temperature derivative of the detonation velocity can be estimated from the initial density derivative of the detonation velocity. In addition, the C-J pressures are estimated using the initial temperature dependence of the detonation velocity.
initial state dependency of detonation, C-J hypothesis, J-M-S relation, PETN