Hybrid Detonations in Oats Dust Clouds in Methane-Air Mixtures

Detonation waves in oats dust clouds in methane-air mixtures were investigated experimentally. Tests were carried out in a vertical tube 4,5 m long with an 8cm internal diameter. The hybrid mixture was ignited by a shock wave generated by means of the detonation of an oxygen-hydrogen stoichiometric mixture in the driver section. Flame propagation was recorded with the use of a streak camera and pressure profiles were measured at selected tube positions. It was found that hybrid detonations are possible in oats dust clouds in methane-air ixtures for a range of methane concentrations from 8.5% to 14.5%, with oats dust concentrations not greater than 0.1 kg/m 3 . Moderate concentrations of oats dust were found to promote transition to detonation, but this depends on the composition of the gaseous mixture; higher concentrations act as a suppressant.