Effects of Cellular Structure on the Behavior of Gaseous Detonation Waves under Transient Conditions

摘要

Increased concern about the detonability of gaseous mixtures in unconfined clouds renewed our interest in the behavior of the detonation process under various transient conditions, such as a nonuniform distribution of pressure, temperature, or composition. In readjusting itself during such a transient state, the process may either survive and continue as a detonation wave or may weaken so fast that it transforms into a simple deflagration wave. A similar transient condition may be imposed on the wave by letting it pass through an area change. Here again, the wave may either survive or weaken to a point of its extinction. Assuming that the cellular structure of the detonation wave is responsible for its existence and its uniqueness, the effect of variation in the cross-sectional area of the tubes on the cell size and on the survival of the detonative process during the transition were investigated. Comparison was made with the results of other investigators who performed similar experiments for different reasons. the results show that it is not the tube diameter nor the initial pressure of the medium that controls the survival of the wave but that it is (1) the number of cells available to endure losses from flow effects generated by the transient conditions and (2) the number of cells remaining to regenerate new cells to revive the detonation process. (ERA citation 04:050656)