ADVANCED METHODS FOR DETERMINING THE ORIGIN OF VAPOR CLOUD EXPLOSIONS CASE STUDY:2006 DANVERS EXPLOSION INVESTIGATION

摘要

At approximately 2:46 AM on November 22, 2006, the largest explosion in the history of Massachusetts occurred in Danvers in an ink and paint manufacturing facility. The explosion was caused by an accumulation of gas or vapors within the facility that was subsequently ignited. The blast completely destroyed the 1,400 m~2 (15,000 ft~2) facility and caused significant damage to the surrounding property and structures. Broken windows were observed up to 1.6 km (one mile) from the facility. In addition, residences immediately to the north and commercial structures to the west were severely damaged by the blast. The ensuing fire burned in the facility for hours after the explosion. Some key observations regarding the near-field blast damage include: (1) the walls of a production room were observed to have been blown outward during the explosion and must have been due to a significant overpressure early in the explosion, (2) directional damage within the facility that included lifted and bent mezzanine grating, and (3) damage to the neighboring structures outside the facility. Using the advanced dispersion and explosion CFD software FLACS, it was possible to investigate the chain of events leading to the explosion. This included evaluating potential ignition sources within the facility and the corresponding explosion itself, by comparing the simulated overpressures of the exploding fuel-air cloud with the near-field blast damage within and outside the facility. Simulations demonstrated that the Danvers explosion was far from trivial to understand and that the resulting blast-damage was very dependent on the details of the exploding fuel-air mixture. This study showed how only certain ignition locations within the facility storage room were capable of reconciling the observed near-field blast damage, and hence the origin of the explosion was identified. The study further demonstrates how advanced CFD tools such as FLACS provide invaluable analyses for explosion investigations.