Studies of premixed flame propagation in explosion tubes

An experimental and theoretical study of premixed flame propagation in a nu mber of small-scale, cylindrical vessels is described. The study provides f urther understanding of flame propagation and the generation of overpressur e in explosions, and allows the assessment of a mathematical model of explo sions through comparisons with the experimental data obtained. Laser sheet images and data gathered on flame location, shape, and overpressures genera ted during the course of explosions in an empty vessel and obstacle-contain ing enclosures elucidate the dynamics of the various combustion processes o ccurring in the different chambers of the vessels. In particular, flame pro pagation through the vessels, up until flame front venting, is found to be substantially laminar, with significant overpressure only being generated i n the later stages of explosions due to rapid turbulent combustion in the s hear layers and recirculation zones induced by the obstacles. Comparisons b etween measurements and predictions also demonstrate that the mathematical model described provides a reasonable simulation of explosions within obsta cle containing enclosures of the type investigated, with rapid turbulent co mbustion being predicted with sufficient accuracy to yield reasonable resul ts for the overpressures generated. (C) 1998 by The Combustion Institute.