The suspension balance model (SBM) for viscous Stokes flow has been well studied for the case of
identical, monodisperse spherical particles in a channel, however, more work remains to be done to
explore the bidisperse and polydisperse SBM. We present a simple extension of the SBM that allows
for modeling of suspensions of particles of bidisperse size. The comparison with avaiable experiments
and direct simulations is found to be good. Additionally, we present a range of simulations to justify
the assumptions made in the polydisperse suspension balance model for non-Brownian, neutrally
buoyant particles that vary in size with a bidisperse distribution. The aim is to study the effects of
moderate size variation on the rheology of the suspension and the distribution of the particles across
the flow, especially in the near-wall regions. It is shown that, at the size ratios considered, bidispersity in the particle size does not significantly affect rheological parameters including the particle
volume fraction and relative viscosity in the bulk of a Couette flow. The particle phase stresses are
distributed between small and large particles in proportion to the relative volume fractions of each
species. In bidisperse suspensions, the large particles in the wall layer develop a spatial structure
and form chains in the streamwise direction.
Published: January 26, 2023
Citation
Howard A.A., M. Maxey, and S. Gallier. 2022.Bidisperse suspension balance model.Physical Review Fluids 7, no. 12:Art. No. 124301.PNNL-SA-171996.doi:10.1103/PhysRevFluids.7.124301