This paper provides solutions to mitigate the effect of bridging/arching for cohesive and noncohesive solid flow in a screw feeder in connection to our previous paper on the underlying mechanisms.
Q. F. Hou, K. J. Dong, A. B. Yu. DEM study of the flow of cohesive particles in a screw feeder. Powder Technology 256 (2014) 529-539.
aARC Research Hub
for Computational Particle Technology, Department of Chemical Engineering,
Monash University, Clayton, VIC 3800, Australia
bCenter for
Infrastructure Engineering, Western Sydney University, Penrith, NSW 2751,
Australia
cCenter for Simulation and Modelling of Particulate Systems,
Southeast University - Monash University Joint Research Institute, Suzhou
215123, PR China
Abstract
Screw feeders are
widely used in industries to transfer granular materials at relatively precise
rates. Often, granular materials can have a certain level of cohesiveness which
can significantly affect the transport among other factors. The critical
mechanism that can stop granular flow is the formation of bridge or arching. In
this work, novel screw designs are proposed to promote cohesive solid flows in
a screw feeder. First, through a numerical model based on the discrete element
method, it is demonstrated that the new designs are effective. Then, the
underlying mechanism is analyzed both macroscopically in terms of particle flow
pattern, velocity field and the motion of screw and microscopically in terms of
temporal and spatial variations of contact force between particles. It is
revealed that the new screw designs can induce a bulk perturbation to the
granular material in the bin in addition to the existing local perturbation by
the screw blade. Thus, the formation of bridge can be deterred, and the
cohesive solid flow is promoted. It is suggested that such designs could also
be effective to non-cohesive granular materials. Further study should be
conducted to optimize the designs.
Keywords: screw feeder; cohesive granular
materials; new screw blade design; perturbation
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