Numerical Simulation of Oblique Detonation Initiation by a High-Velocity Body Flying in a Hydrogen-Air Mixture
I. A. Bedarev, A. A. Syrovaten, V. M. Temerbekov
Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: oblique detonation, numerical simulation, detonation cells, hydrogen-air, initiation energy
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 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.
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