A study on the obstacle-induced variation of the gas explosion characteristics

A study on the variation of the gas explosion characteristics caused by the built-in obstacles was conducted in enclosed/vented,gas explosion vessels. It has been well known that the obstacles in pipes and long ducts would ac celerate the flame propagation, and cause the transition from deflagration to detonation. In this study, the explosion characteristics and the flame b ehavior of vented explosions and constant-volume explosions were investigat ed. Experiments were carried out in a 270-liter and 36-liter hexahedron ves sels filled with LPG-air mixture. The explosion characteristics of the gas mixture were determined by using a strain-responding pressure transducer. T he flame behavior was recorded by using a high-speed video camera. The shap e and the size of the obstacle, and the gas concentration, were adjusted in the experiments. It can be seen from the experimental results that, instead of being acceler ated, the flame propagation inside the explosion vessel is decelerated by t he plate obstacles fixed at the bottom of the vessel. Also, the characteris tics of the enclosed explosion are not so affected by the built-in obstacle s as those of the vented explosion are. It is believed that the eddy-induce d turbulence behind the obstacle decelerates the flame propagation. (C) 200 1 Elsevier Science Ltd. All rights reserved.