The influence of confinement geometry on deflagration to detonation transition in gases

Abstract
Among all the phenomena relative to combustion processes deflagration to detonation transition is, undoubtedly, the most intriguing one. Deflagration to detonation transition (DDT) in gases is relative to gas and vapor explosion safety issues. Knowing mechanisms of detonation onset control is of major importance for creating effective mitigation measures addressing the two major goals: to prevent the DDT in case of mixture ignition, or to arrest the detonation wave in case it was initiated. Hydrocarbon fuel-air mixtures are of great interest, because accidental release of flammable natural gas into the atmosphere may have severe consequences, the accidents at Flixborough (1974, UK), Mexico City (1984) and Ufa (1989, Russia) being extreme examples of how dangerous such releases are. The paper contains the results of theoretical and experimental investigations of control of the DDT processes in hydrocarbon - air gaseous mixtures. The influence of geometrical characteristics of the confinement and flow turbulization on the onset of detonation and the influence of temperature and fuel concentration in the unburned mixture are discussed.