Science and Technology of Energetic Materials

Vol.62, No.6 (2001)

Research paper

Transverse wave structures of H2-O2-diluent two-dimensional detonations and the relation to the second explosion limit(*in Japanese)
Kazuaki Inaba, Akiko Matsuo, and Katsumi Tanaka


Two - dimensional computations of the propapting detonations in a stoichiometric hydrogen - oxygen diluted with nitrogen or argon mixture (2H2 + O2 + 3.76N2 / 3.76Ar) were performed using a detailed chemical reaction mechanism. The transverse wave strength was defined as the dimensionless pressure increase across the renect shock and was deternined for the different channel widths at initial pressures 1.000, 0.421, and 0.132 atm. The shock structure of the detonation propagating through a narrow chanel evolved just from a single Mach structure to a double Mach structure. Unreacted pockets were cut off by the transverse wave collisions, but they immediately burned. When a detonation propagated through a wide channel, the shock strucure evolved continuously from a single Mach structure to a complex Mach structure, except for the hydrogev - oxygen mixture diluted with argon at 0.132 atm. The channel width, Wmax, was the widest one in which a single transverse wave appeared, and showed good agreement with the cell width of the previous experimental cell widths. In the hydropn - air mixture at initial pressure 1.000 and 0.421 atm, the transverse wave strength increased up to 1.50 with increasing the channel width, and the strong transverse detonation occurred. There was a close relation between the second explosion limit and the occurrence of the strong transverse detonation observed in hydrogen - air mixture at 1.000 and 0.421 atm. Since the frontal shock oscillated, the post - shock condition varied across the second explosion limit. Steep increasing of the induction length might cause the onset of the strong transverse detonation. We suggested that the irregularity of the H2+Air detonation was connected with the occurrence of the strong transverse detonations.

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