Influence of pine wood dust layer width on flame propagation under horizontal rotating conditions

Abstract

In response to the issue of wood dust layers accumulating on the surfaces of rotating equipment in wood product enterprises, which may potentially trigger fire incidents, relevant literature has been studied. However, the effect of the width of pine wood dust layers in a horizontal rotating state on flame propagation has not been reported. To address this, experiments were conducted under 12 different conditions, varying the width of the pine dust layers (2 cm, 3 cm, and 4 cm) and the rotational angular velocities (0 rad/s, 0.023 rad/s, 0.083 rad/s, and 0.167 rad/s). Parameters were investigated, including flame height, propagation speed, mass loss rate, and temperature changes during the flame propagation process. The results indicated that the flame shape transitioned over time from linear to U-shaped, and ultimately to V-shaped; within a certain range, both the average flame height and the average flame propagation speed initially increased and then decreased as the sample width increased. The most hazardous condition for flame propagation was identified as sample 5, which had a width of 3 cm and a rotational angular velocity of 0 rad/s. Furthermore, this study established a heat transfer model for flame propagation in pine dust layers and derived an equation for the total heat flux in the preheating zone. It was noted that during the flame propagation process in the pine dust layer, heat transfer was primarily influenced by flame radiation and solid conduction.