Mechanisms of vapor cloud explosion and its chain reaction induced by an explosion venting flame

This experimental study focused on vapor cloud explosion and its chain reaction induced by an explosion venting flame. Two vapor clouds were installed in front of the explosion venting container along the horizontal direction. Explosion flame evolution process was recorded by a high-speed camera and a schlieren system. Pressure sensors at different locations were used to acquire the pressure data. The temperature data were collected by a high-speed infrared thermal imager and three thermocouples. The changes in flame propagation characteristics, flame temperature, and pressure distribution were determined, and the mechanisms of the vapor cloud explosion and its chain reaction induced by the venting flame were deeply analyzed. Results indicate that the venting flame could induce vapor cloud explosion and set off a chain reaction, leading to the high explosion intensity. As for the ignition condition, the venting flame directly came in contact with the vapor cloud and provided the required energy for the ignition. The pressure first increased and then decreased as the distance from the venting port increased, and the highest pressure appeared in the central region of the vapor cloud. The temperature distribution also presented a similar phenomenon.