Experimental study of fire spread in mixed piles of wood dust and shavings

Compared with the pure wood dust layer, mixed piles of wood dust and shavings are more common in actual wood processing workshops, and their fire risk cannot be ignored. In this paper, the fire spread characteristics of wood dust, shavings, and mixed piles with different ratios of the two were investigated using the experimental platform of fire spread in dust layers. Aiming at the characteristics of such mixed piles with high stacking voids, the influence of the voids on the fire spread of stacked dust was analyzed from the perspectives of temperature distribution, flame spread velocity (FSV), and heat transfer. Considering the influence of voidage on the thermal conductivity and emissivity of the dust layer, a prediction model for FSV was proposed. The results showed that FSV presented a trend of decreasing and then increasing with the increase of shavings addition in the mixed accumulation dust. The small amount of shavings added (<50%) instead suppressed the FSV, which may be related to the change in the shape of the flame front. The increase in the voidage promoted the heat radiation transfer efficiency in general, thus contributing to the fire spread of the stacked dust.