Studies of premixed flame propagation in explosion tubes

An experimental and theoretical study of premixed flame propagation in a number of small-scale, cylindrical vessels is described. The study provides further understanding of flame propagation and the generation of overpressure in explosions, and allows the assessment of a mathematical model of explosions through comparisons with the experimental data obtained. Laser sheet images and data gathered on flame location, shape, and overpressures generated during the course of explosions in an empty vessel and obstacle-containing enclosures elucidate the dynamics of the various combustion processes occurring in the different chambers of the vessels. In particular, flame propagation through the vessels, up until flame front venting, is found to be substantially laminar, with significant overpressure only being generated in the later stages of explosions due to rapid turbulent combustion in the shear layers and recirculation zones induced by the obstacles. Comparisons between measurements and predictions also demonstrate that the mathematical model described provides a reasonable simulation of explosions within obstacle containing enclosures of the type investigated, with rapid turbulent combustion being predicted with sufficient accuracy to yield reasonable results for the overpressures generated. (C) 1998 by The Combustion Institute.