On the Investigation of Detonation Re-initiation Mechanisms and the Influences of the Geometry Confinements and Mixture Properties

Abstract

The topic of detonation re-initiation is studied through both experimental measurements and numerical simulations using a bifurcation channel and the detonation research facilities in Temasek Laboratories. The main objective is to understand the re-initiation mechanisms through shock reflections, and investigate the performance of detonation re-initiation at different test conditions. Stable and unstable detonation waves are both taken into consideration. It is found that the re-initiation through shock reflection is mainly achieved through the interactions of the multiple transverse waves. The details of the generation and evolution of the transverse waves are also clarified. The influence of the geometry confinement to detonation re-initiation is investigated. It is found that the length of the bifurcation channel can affect the re-initiation results by limiting the shock reflection times, which is discovered to be the main reason leading to the discrepancies between the previous similar studies. The width of the bifurcation channel is also critical as it can directly affect the induction length during detonation diffraction which determines the shock reflection strength. The differences of re-initiation using various mixture properties are also addressed, and a sudden transitional behavior of detonation re-initiation is found between stable and unstable detonation waves. Regarding the reason why a certain number of shock reflections are required before successful re-initiation, it can be explained using the relative relation between the shock reflection strength and the corresponding marginal solution curve of a quasi-steady detonation. 200