Figure 12. Averaged angular velocity of large particles for different
blends.
4.4 Particle interactions
In addition to the large particle rotation, different particle mixtures
may have different particle interactions that also contribute to the
shear stress difference. The contact numbers for three contact types,
i.e. the contact between large and large particles L-L, large and small
particles L-S, and small and small particles S-S, are shown in Figure
13. While only L-L contacts and S-S contacts exist for monodispersed
large and small particles, respectively, the number of S-S contact
dominate the numbers of the other two types of contacts. The number of
S-S contacts for the three binary mixtures decreases with increasing
mass fraction of large particles, as a lower large particle mass
fraction leads to a higher number of small particles and a higher number
of S-S contacts.