A study of pressure-driven displacement flow of two immiscible liquids using a multiphase lattice Boltzmann approach

The pressure-driven displacement of two immiscible fluids in an inclined channel in the presence of viscosity and density gradients is investigated using a multiphase lattice Boltzmann approach. The effects of viscosity ratio, Atwood number, Froude number, capillary number, and channel inclination are investigated through flow structures, front velocities, and fluid displacement rates. Our results indicate that increasing viscosity ratio between the fluids decreases the displacement rate. We observe that increasing the viscosity ratio has a non-monotonic effect on the velocity of the leading front; however, the velocity of the trailing edge decreases with increasing the viscosity ratio. The displacement rate of the thin-layers formed at the later times of the displacement process increases with increasing the angle of inclination because of the increase in the intensity of the interfacial instabilities. Our results also predict the front velocity of the lock-exchange flow of two immiscible fluids in the exchange flow dominated regime. A linear stability analysis has also been conducted in a three-layer system, and the results are consistent with those obtained by our lattice Boltzmann simulations

Lattice Boltzmann Simulations of Some Novel Multiphase Flows

Multiphase flows can be observed in many naturally occurring phenomena such as rain, snow, avalanches, clouds, underground water flows, sea waves, etc. Multiphase flows are also common in many industrial processes, such as transportation of crude oil in pipelines; enhance oil recovery, hydrology, filtration, coating, and many other applications. In food processing industries, the clean- ing of plants involves the removal of highly viscous fluid by fast flowing water streams injected at the inlet of the conduits. Therefore, the fundamental understanding of such flows is essential, thus at- tracting many experimentalists and theoreticians to investigate the miscible and immiscible systems in various flow configurations

Lattice Boltzmann Simulations of Some Novel Multiphase Flows

Multiphase flows can be observed in many naturally occurring phenomena such as rain, snow,\ud avalanches, clouds, underground water flows, sea waves, etc. Multiphase flows are also common\ud in many industrial processes, such as transportation of crude oil in pipelines; enhance oil recovery,\ud hydrology, filtration, coating, and many other applications. In food processing industries, the clean-\ud ing of plants involves the removal of highly viscous fluid by fast flowing water streams injected at the\ud inlet of the conduits. Therefore, the fundamental understanding of such flows is essential, thus at-\ud tracting many experimentalists and theoreticians to investigate the miscible and immiscible systems\ud in various flow configurations.\u

Three-Dimensional LBM Simulations of Buoyancy-Driven Flow Using Graphics Processing Units

Three-dimensional simulations of buoyancy-driven flow of two immiscible liquids are performed using lattice Boltzmann method (LBM) implemented on a graphics processing unit (GPU). Graphics processing unit is a new paradigm for computing fluid flows and has become more popular in the recent years. It is a powerful and convenient to use. LBM, which is an excellent alternative technique for fluid flow simulation, when implemented on GPUs gives a very high computational speed-up. Our present GPU based LBM solver gives a speed-up 25 times corresponding CPU based cod

A lattice boltzmann simulation of three-dimensional displacement flow of two immiscible liquids in a square duct

A three-dimensional, multiphase lattice Boltzmann approach is used to study a pressuredriven displacement flow of two immiscible liquids of different densities and viscosities in a square duct. A three-dimensional, 15-velocity (D3Q15) lattice model is used. The effects of channel inclination, viscosity, and density contrasts are investigated. The contours of the density and the average viscosity profiles in different planes are plotted and compared with those obtained in a two-dimensional channel. We demonstrate that the flow dynamics in a three-dimensional channel is quite different as compared to that of a two-dimensional channel. We found that the flow is relatively more coherent in a three-dimensional channel than that in a two-dimensional channel. A new screw-type instability is seen in the three-dimensional channel that cannot be observed in the two-dimensional channel

Multiphase lattice Boltzmann simulations of buoyancy-induced flow of two immiscible fluids with different viscosities

We study the effects of viscosity differential on buoyancy-induced interpenetration of two immiscible fluids in a tilted channel using a two-phase lattice Boltzmann method implemented on a graphics processing unit. The effects of viscosity differential on the flow structures, average density profiles and front velocities are studied. Relatively stable fingers are observed for high viscosity ratios. The intensity of the interfacial instabilities and the transverse interpenetration of the fluids are seen to increase with decreasing viscosity differential of the fluid