DEFLAGRATION-TO-DETONATION TRANSITION IN POROUS ENERGETIC MATERIALS ATTENDED BY FORMATION OF A SECONDARY PRESSURE WAVE

One of the two deflagration-to-detonation transition types in solid en ergetic materials attended by formation and development of secondary ( post-convective) exothermic chemical reaction and compression waves. A n experimental technique enabling luminous reaction fronts and pressur e variations in time at several points along the charge to be monitore d concurrently was employed to systematically study the conditions und er which the secondary wave arises and to measure parameters of this w ave. Experiments were conducted with several materials varying their i nitial density, grain size, and igniter power. As the grain size and s ample density vary, the transition type changes: whereas with a fine-g rained material deflagration-to-detonation transition occurs with form ation of a secondary wave, in the same coarse-grained material this tr ansition occurs with no secondary wave. Plausible mechanisms of second ary-wave formation are discussed.