High speed turbulent deflagrations and transition to detonation in H2-air mixtures
Experiments on flame acceleration and transition to detonation in H2-air mixtures in long tubes (L/D greater than 200) are reported. Obstacles in the form of a spiral coil with blockage ratio (BR) equal to 0.44 and repeated orifice plates with BR of 0.44 and 0.6 were used in a 5-cm diameter tube. Steady-state flame (or detonation) speeds were attained over a flame travel of 10-40 tube diameters. A sharp transition occurs at about 13 percent H2 when the flame speed reaches supersonic values. A second transition to a quasi-detonation regime occurs near the stoichiometric composition when the flame speed reaches a value of the order of 800 m/s. At about 17 percent H2 transition to normal C-J detonation occurs when the flame exits into the smooth obstacle-free portion of the tube. The present results demonstrate that transition is only possible in a given tube if the detonation cell size is less than the pi-D value for single-head spin. 17 references.
- Research Organization:
- McGill Univ., Montreal, Canada
- OSTI ID:
- 6380529
- Journal Information:
- Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 56; ISSN CBFMA
- Country of Publication:
- United States
- Language:
- English
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