Spherically imploding detonation waves initiated by two-step divergent detonation

The detonation chamber developed by K. Terao and H. G. Wagner in Gottingen has been improved, in order to concentrate the combustion energy more effectively to a focus, so that imploding detonation waves are initiated by two-step divergent detonation waves in a hemispherical space having an effective diameter of 500 mm. The imploding detonation waves are investigated by measuring their propagation velocity using ion probes and pressure variations at different positions in the space by a piezoelectric pressure transducer, while the temperature in the implosion center is measured by a laser light scattering method. The results suggest that the peak pressure at the detonation front increases with the propagation to the center more rapidly than that in the Gottingen apparatus, while the propagation velocity is almost the same. A temperature from 107 K to 108 K is also observed in the focus of the imploding detonation waves.