Forced convection fire spread along wooden dowel array

The effects of freestream flow on fire spread behaviors of a discrete wooden fuel array were studied. The spacing between fuel elements was varied, and the flame spread behavior under 1, 2, and 3 m/s forced flow velocities was investigated. The fastest spread rate was not observed for the smallest spacing. Furthermore, increasing spacing did not necessarily lead to a slower spread, as seen with the flame spread along the 0.75 cm spaced array which was as fast or faster than the 0.5 cm spacing condition. At a spacing of 1 cm, fragmented flames were observed at wind speeds of 3 m/s that coincided with a slower spread rate than the 2 m/s wind conditions. The anomalies were explained using flame visualization and pitot probe measurements to determine the effects of flow speed at different spacing conditions. It seems that a coupling between the combustion and fluid dynamics of flow around the dowel cylinders under certain conditions strongly affects the fire spread behaviors.