Experimental Investigation of Flame Propagation Caused by Interfaces of the Flame, Turbulence Eddies, and Negative Shock Waves
Vijaya Kumar Cheeda
Detonation Dynamics and Explosion Study Center, Tirupati-101, Andhra Pradesh, India
Keywords: fire safety in confined space, obstacle spacing, turbulence intensity, flame acceleration, vortex field, Richtmyer-Meshkov instability
Abstract
Fire accidents in closed regions, transport carriers, and auditoriums are influenced by the confinement conditions. The current experimental investigation is intended to find the effect of obstacles, obstacle-free space, gas flow, and near-wall turbulence on the flame acceleration. Two rows of bench-shaped obstacles (replicate chairs in transport carriers) enhance the flame speed in the obstacle-free path. Turbulence intensity is higher in local regions where the flow becomes highly subsonic and mildly supersonic, which enhances the flame speed. The flame front-driven supersonic flow can form negative shock waves, which can further increase the flame speed. Careful design of confined geometry can prevent accidents or slow down the flame propagation.
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