Numerical simulation of oblique detonation initiation by a high-velocity body flying in a hydrogen-air mixture

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 regimes 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 a detached oblique detonation wave, which was not observed in previous experiments, at 125 kPa. At 100 kPa, a regime of shock-initiation combustion is observed. Based on an analytical dependence, the energy of detonation initiation by a high-velocity body is estimated, and the analytical and numerical data are found to be in good agreement.