A technique for promoting detonation transmission from a confined tube into larger area for pulse detonation engine applications

A simple method of detonation transmission from a small tube to a large area is presented. This technique involves placing obstacles which create slight blockages at the exit of the confined tube before the planar detonation emerges into the larger space, thereby generating flow instability to promote the detonation transmission. In this experimental study two mixtures of undiluted stoichiometric acetylene-oxygen and acetylene-nitrous oxide are examined. These mixtures can be characterized by a cellular detonation front that is irregular and representative of those potentially used in practical aerospace applications. The blockage ratio imposed by the obstacles is varied systematically to identify the optimal condition under which a significant reduction in critical pressure for transmission can be obtained. A new perturbation configuration for practical use in propulsion and power systems is also introduced and results are in good agreement with those obtained using thin needles as the blockage ratio is kept constant.