We propose a mesoscopic model of binary fluid mixtures with tunable viscosity ratio based on a two-range pseudopotential lattice Boltzmann method, for the simulation of soft flowing systems. In addition to the short-range repulsive interaction between species in the classical single-range model, a competing mechanism between the short-range attractive and midrange repulsive interactions is imposed within each species. Besides extending the range of attainable surface tension as compared with the single-range model, the proposed scheme is also shown to achieve a positive disjoining pressure, independently of the viscosity ratio. The latter property is crucial for many microfluidic applications involving a collection of disperse droplets with a different viscosity from that of the continuum phase. As a preliminary application, the relative effective viscosity of a pressure-driven emulsion in a planar channel is computed.
Fei, L., Scagliarini, A., Montessori, A., Lauricella, M., Succi, S., & Luo, K.H. (2018). Mesoscopic model for soft flowing systems with tunable viscosity ratio. PHYSICAL REVIEW FLUIDS, 3(10) [10.1103/PhysRevFluids.3.104304].