Numerical Study on Hydrogen Detonation Initiation through an Inhomogeneous Thermal Explosion

Abstract

Detonation initiation through an inhomogeneous energy source is studied using one-dimensional simulations. The energy source is divided into two segments, called segment A and segment B. The initial temperature and the length of two parts energy source are varied to provide different auto-ignition delay time and strength of the leading shock. Detailed chemical reaction mechanism is used for a stoichiometric hydrogen/oxygen mixture diluted by 70% Argon. According to the initial thermodynamic parameters, four different regimes of detonation initiation were found in the present study, namely high-critical, low-critical, low-subcritical and high-subcritical regimes. The critical temperature and internal energy in the inhomogeneous energy source to initiate the detonation are analyzed. It was found that, as we fix the length and temperature of segment B, by changing the temperature of segment A, there are two critical temperatures, called high critical temperature and low critical temperature. When the temperature of segment A higher than the high-critical temperature or lower than the low-critical temperature, there is no detonation occurs. As we change the length ratio of segment A and B, the same results was found. In addition, the relationship between the length ratio of segment A and B and the energy to initiate detonation are also studied.