Experiments on flame spread of a fuel droplet array in a high-pressure ambience

Flame spread phenomena in a suspended fuel droplet array were experimentally investigated for n-decane and n-hexadecane in a high-pressure ambience. Seven droplets of the same size were arranged at equal horizontal spacings. Flame spread rates were measured based on OH emission histories detected by a high-speed video camera with an image intensifier for droplet diameters of 0.50, 0.75, and 1.0 mm at ambient pressures from 0.1 to 2.0 MPa. Results show that, as droplet spacing becomes smaller, flame spread rate increases and attains a maximum value at a specific spacing. A further decrease in droplet spacing causes the spread rate to decrease due to the large latent heat of vaporization. Experiments were also conducted in a microgravity field to determine if these characteristics of flame spread are affected by natural convection.