Figure 5 – Normalized flow rate of bulk solid as a function of the cutter heights.
Figure 5 presents an interesting outcome from the experimental work which requires further investigation. This outcome is a flow rate that is not directly proportional to the cutter height. Consider that at a cutter height of 30mm the flow rate is normalised to unity. At a cutter height of 15mm, the total mass flow rate is some 65% of the previous case. At this stage our belief is that this is partially a result of entry blocking with the taller cutters forcing an increasing percentage of material to evade capture by the cutters by creating a shear plane in front of the cutter that facilitate particles to rise up over the cutters and remain in the bed. The bed upheaval is clearly evident in both the physical and discrete element models [2]. The DEM work in progress indicates that this upheaval is a function of bed depth and an increasing bed depth leads to a reduction in bed disturbance.