Science and Technology of Energetic Materials

Vol.73, No.2 (2012)

Research paper

Hydrogen-air detonability limits in long tubes obtained using detonative driver gases
Teruhito Otsuka, Satoshi Tsuge, and Norihiko Yoshikawa


The unstable phenomena near the lean detonability limits in atmospheric hydrogen-air mixtures are shown using 20-25-m-long test sections of 28, 53, and 105mm inner-diameter gas-supply tubes. The driver section of the apparatus is charged with stoichiometric hydrogen-oxygen mixture to inject a detonation wave into the test section. Stronger equimolar acetylene-oxygen mixture and weaker 20 vol.% hydrogen-air mixture are also used as driver gases. Three propagation modes of deflagration, galloping detonation, and stable detonation are identified in quasi steady-state regimes. The detonability limits are 18 vol.% for the 28mm ID tube, 15 vol.% for the 53 mm ID tube and 16 vol.% for the 105mm ID tube. The results show that the pitch length of galloping detonations is about 10-15m. This suggests that a longer test section is required to examine the self-sustainability of galloping detonation.

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hydrogen, detonability limit, self-sustainability

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