Mechanisms of Blast-Fire Interaction

摘要

The objective of this investigation was to obtain a more basic understanding of the physical mechanisms by which blast waves interact with fires. This information is needed to ensure that the correlation functions to be used in formulae for predicting the extinction or enhancement of fires by nuclear blast waves will include all the controlling variables. The study was limited to wood fires and fires over liquid hydrocarbon fuels. Flames were displaced from burning wood surfaces by blast waves propagating parallel to the burning surface in all tests. At low blast strength, flame persisted in crevices in the char surfaces to reignite the fire. At high blast strength, glowing combustion of the char was stimulated. Fires burning over flat wicks containing a liquid hydrocarbon were displaced off the wick in all tests. Reignition of the wick by flames swept into the wake depended on whether the vapor pressure over the liquid fuel was reduced enough, by cooling the liquid, so that concentration of fuel vapor flowing into the wake was depressed below the flammability limit before the end of the positive phase of the flow. Keywords: Fire Extinction Mechanisms; Airblast Simulation; Blast/fire Interactions; Flame Suppression; Fire Extinction By Air Blast; Fast Rising Air Flow Without Shocks.