Gaseous Detonations. II. Initiation by Shock Waves¹

Experimental study on transmission of an overdriven detonation wave from propane/oxygen to propane/air

“…Two circulation pumps, one for each section, were used for about 10 min at the same time to ensure the homogeneity of the two mixtures. One may note that the previous studies indicate that the use of the diaphragm has an influence on the wave transmission [8,13,24]. In order to evaluate this effect, another experiment using a smoked foil to record the tracks of the detonation cellular structures across the diaphragm was addressed, which is discussed in Section 4.2.…”

“…These authors also show that the transmission of a detonation wave to a weaker mixture was as effective with the diaphragm as without. In addition, Berets et al [8] indicate that the diaphragm causes a time delay. Campbell et al [24] suggest that this time delay comes from the times required for the detonation wave to break the diaphragm and/or by the damped detonation wave caused by the diaphragm to reinitiation.…”

“…It can therefore be expected that an overdriven detonation wave propagating into a less sensitive mixture may sustain a detonation wave with some degree of overdrive with respect to the propagation of a CJ detonation wave. Transmission of detonation waves from one mixture to another has been studied from the 1950s [8][9][10][11][13][14][15][16]. It must be noted that these studies were performed within a straight tube of constant bore.…”

“…Most of these studies used a detonation wave from a donor propagating into a buffer section with a nonreactive mixture to generate shock waves. These studies observed a shock-induced ignition process, known as the shock-to-detonation transition (SDT) [12], in the acceptor mixture [8][9][10][11]. Effects of mixture properties, shock strength, gradients of mixture compositions, and initiator lengths were examined.…”

Recent Advances in Gaseous Detonation

“…Shock and detonation tubes have been used to measure the velocity of propagation of C-J detonations (17,27,29). Experimental work in this area is difficult because of the very fast response instrumentation required.…”