CHAPMAN-JOUGUET DEFLAGRATIONS

Two types of quasi-steady high-speed deflagration have been observed experimentally. In the first place they are reaction-waves created in, and propagating through, rough tubes and tubes that contain obstacles; in the second place they are deflagrations created from established detonations by eliminating the transverse waves from the latter's structure. Changes in tube roughness, obstacle size and tube diameter have no significant influence on the speeds at which the deflagrations propagate. These speeds are close to sonic relative to product gases flowing out of the reaction-waves, and both classes of deflagration are observed to travel at about one-half of the corresponding Chapman-Jouguet (CJ) detonation speed. A theoretical analysis has been carried out on a configuration that consists of a plane precursor shock-wave driven by a plane CJ deflagration. Results agree very well with observations and support the idea that, at least for the duration of these observations, this combination of shock and deflagration is controlled by the energetics of the reacting mixture.