Kinetic Theory for the Shear Viscosity of Dense Binary Dipolar Fluid Mixtures

We construct a kinetic theory for the shear viscosity of dense binary fluid mixtures of strongly-interacting dipolar hard spheres. We derive an expression for the pairwise correlations in the binary mixtures that is accurate up to packing fractions around 0.35. The approach is based on Enskog-Thorne theory, and inspired by the theory for dense pure fluids developed by Pousaneh and de Wijn. It relies on effective coupling parameters obtained from the pure fluids combined with mixing rules and a heuristic expression for the collision integral. We compare our results to viscosities obtained numerically from molecular-dynamics simulations of dipolar hard-sphere fluids. Our expression for the shear viscosity of the binary mixtures captures the density and composition dependent behavior of the binary dipolar fluids up to packing fraction of $\xi \lesssim 0.3$ without any mixture-derived fit parameters.