Unconfined vapor cloud explosions: A review of recent theories and experiments

The theory of premixed vapor combustion and gas detonations is discussed. Conditions under which detonation waves can be initiated and sustained in unconfined clouds are indicated. Detonability limits of various gas mixtures in different geometries are outlined. Nonideal explosion phenomena are reviewed. Tests to study the detonability of fuel-oxident mixtures in unconfined geometries, including large balloon tests conducted with explosive initiators and detonation wave (from a pipe) initiators are described. Tests involving passive ignition of large vapor clouds in the open and vapor clouds in semiconfined situations are summarized. Tests to determine the effect on turbulent flame propagation speeds due to obstacles in the flame path are also reviewed.