ID#: 51
Abstract Title: On The Controlled Generation and Detailed Observation of the Onset of Detonation
Session Title: Detonation Initiation
Session Date: 8/1/01
Session Start Time: 8:30 AM
Contributing Author: Thomas, G.O.
Organization: University of Wales
Country: U.K.
Authors: Richard Bambrey, Geraint Thomas
Short Abstract: The detailed observation of deflagration to detonation transition (DDT) is inherently difficult due to the stochastic nature of the flame acceleration processes that lead to shock formation, which in turn gives rise to the conditions required for detonation to start. The paper describes how shock tube techniques have been used to generate the conditions required for the development of detonation in a more direct manner. The most detailed observations of the onset of detonation that are reported in the paper were obtained following the auto-ignition of stoichiometric ethylene-air diluted with 75% argon in the reflected shock region. After a further delay, in excess of a millisecond, local compression fronts were seen to form ahead of parts of the evolving turbulent flame. These then led rapidly to the onset of detonation. The paper will discuss the prevailing gasdynamic and thermodynamic state of the gas in the reflected shock region and how these may have contributed to the onset of detonation.