Investigation of flame propagation over an inclined fuel wetted porous bed

• We examined the rate of flame spread over an inclined porous bed wetted with liquid fuel.
• The rate of flame spread decreases as the porous bed inclination increases.
• Size of particles has strong effect on the rate of flame spread.
• Flame propagation over porous bed under different conditions can be explained by Damkohler number.

This experimental study was conducted to investigate the rate of flame spread over an inclined porous solid (sand) wetted with finite quantities of fuel (iso-propanol). The study comprised experiments that were conducted over 15° and 30° inclined beds with depths ranging from 13.3 mm to 39.9 mm and consisting of average sand particle diameters ranging from 0.5 mm to 5 mm under quiescent, assisted and opposed airflow conditions.Analysis of the resulting data indicate that the rate of flame spread is significantly decreased by increasing the bed inclination angle or the airflow velocity and is applicable for both assisted and opposed directions. Furthermore, the rate of flame spread is decreased to the minimum value and actually ceased halfway along the bed with a 30° inclination angle. This behaviour was observed mainly for beds containing coarse sand particles. The rate of flame spread was higher for thinner beds rather coarse beds under any given airflow conditions. Finally, the rate of flame spread in upward direction was relatively quicker in comparison with downward direction counterpart.