Marv Khala

Postgraduate Research Student

Academic and research departments

Department of Chemical and Process Engineering.

My publications


Angus Andrew, Yahia Lyes Ait Ali, Maione Riccardo, Khala Marv, Hare Colin, Ozel Ali, Ocone Raffaella (2020) Calibrating Friction Coefficients in Discrete Element Method Simulations with Shear-Cell Experiments,Powder Technology Elsevier
Discrete Element Method (DEM) simulations coupled with shear cell experimental results have been
used to investigate the flow behaviour of a dry particle assembly of glass beads in the quasi-static regime.
10 Experimental studies have been undertaken using an FT4 powder shear cell apparatus, in parallel with
extensive DEM simulations of both homogeneous simple shear and the FT4 shear cell itself. The findings
show that it is not possible to accurately predict the bulk friction coefficient with homogeneous simple shear
simulations unless both rolling and sliding friction are considered. There are, however, multiple pairs of
sliding and rolling friction coefficients which can reproduce the experimental bulk friction coefficient. Sliding
15 test experiments were conducted to yield the coefficient of sliding friction, and hence minimise the set of
potentially correct pairs. Simulations of the full FT4 shear cell with two different calibration pairs, along
with a pair without rolling friction, were then undertaken to understand the effect of their selection on
realistic wall-bounded shearing conditions. Discrepancies were mainly found in the obtained radial contact
number and velocity profiles, with increasing friction coefficients - particularly sliding friction - found to in20
hibit packing and particle velocity in the shear deformation zone. Comparison between homogeneous simple
shear and shear cell simulation results showed a significant effect of the wall on the obtained force network,
with almost a complete absence of the weakest structures which were seen supporting the strong structures
in the simple shear scenario.