The investigation of viscous fingering phenomenon of immiscible fluids displacement by Lattice Boltzmann method

In this paper, the viscous fingering phenomena of two immiscible fluids with large viscosity ratio was simulated by Lattice Boltzmann method (LBM). The Rothman-Keller Lattice Boltzmann（RK-LB）model was applied to study the viscous fingering phenomena in a microchannel where the large viscous fluids were displaced by small viscous fluids. We have investigated the influences of parameters such as viscosity ratio (M), surface wettability, Capillary number (Ca) and Reynolds number (Re) on finger structures, breakthrough time (Ts), and areal sweep efficiency (Se). In particular, the effects of surface tension and large viscosity ratio on the phenomenon of fluid accumulation were intensively studied. The simulation results showed that the fluid accumulation became more obvious gradually with the increase of M, which led to more serious displacement effects. Moreover, Se increased as the increase of contact angle. Besides, as the viscous fingering phenomenon went weaker, the phenomenon of fluid accumulation became more evident. Furthermore, the finger pattern had a tendency to increase as the value of Ca and Re increased. And the phenomenon of fluid accumulation reduced with the decrease of Ts and Se.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author