New small scale gaseous detonation data compared with Tang and Baker's blast curves : A discussion on the energy to be considered as producing the blast wave after gaseous detonation
Congress title :International Colloquium on the Dynamics of Explosions and Reactive Systems
Congress town :Poitiers
Congress date :23/07/2007
This paper is related to the study of the effects of an explosion and particularly the pressure due to the blast wave induced by a detonation. We report some experimental data obtained previously with the detonation of small gaseous charges and bring a comparison between these data and the theoretical models proposed by Tang, Baker and Baker.
Tang and Baker studies are based on the statement that blast waves obtained after a gaseous detonation and after a TNT detonation would produce different pressure time-history. So that, Baker et al. have proposed an approach to replace the simple TNT equivalency, and have introduced a series of blast curves giving peak positive overpressure or impulse as a function of the distance from the ignition. These charts are typically an alternative to the systematic use of the widespread TNT blast curves when the effects of gaseous explosions and not solid explosive detonation effects are studied. Subsequently, if confirmed experimentally the blast curves exhibited by Tang et al., also known as the Baker-Strehlow-Tang curves, would constitute a very powerful tool to derive a parameter-dependent TNT equivalency.
In the present paper, we compare Tang's blast curves considering very recent results obtained by Trélat et al. at the Laboratoire Energétique Explosion et Structures in Bourges. The use of these new experimental results allows a full comparison with the Baker-Strehlow-Tang curves considering every physical characteristic representative of the pressure pulse induced by the blast wave (peak overpressures, positive and negative impulses, positive and negative durations, arrival time). But first of all, the post processing of the results raises the issue of the choice for a correct value of the energy producing the blast wave after a gaseous detonation, used for scaling the results. Thus we show that the approach chosen to obtain the value of this energy has a significant influence on the adequacy of the results with the theoretical curves. In conclusion, from an engineering statement, we would like to attract researcher's attention on this energy quantity, difficult to define from a physics stand point, but of major importance when used in engineering applications.