Numerical Simulation of Oblique Detonation Initiation by a High-Velocity Projectile Flying in a Hydrogen–Air Mixture

Abstract

A mathematical method is developed for solving the problem of detonation initiation in a hydrogen–air mixture by a small-diameter sphere flying with a velocity greater than the Chapman–Jouguet detonation velocity. The mathematical model verification is performed against experimental data on the detonation cell size in hydrogen–oxygen and hydrogen–air mixtures. Depending on the pressure in the mixture, which is varied from 100 to 250 kPa, three types of oblique detonation waves are obtained: (1) stabilized oblique detonation wave at 250 kPa; (2) stabilized oblique detonation wave of the “straw hat" type at 200 kPa; (3) periodic regime with an attenuated oblique detonation wave, which was not observed in previous experiments, at 125 kPa. At 100 kPa, a regime of shock-initiated combustion is observed. Based on an analytical dependence, the energy of detonation initiation by a high-velocity projectile is estimated, and the analytical and numerical data are found to be in good agreement.