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In this paper, a multi-relaxation-time lattice Boltzmann (LB) model for nanoscale liquid flow is established to investigate the liquid flow characteristics in nanoporous media. The slip length and effective viscosity obtained by molecular dynamics (MD) simulations are adopted to account for the nanoscale effect. First, the LB model for water flow in nanopores is built and water flow characteristics in nanoporous media are investigated. The fluid-solid interaction force shows significant influence on water flow in nanoporous media. The water flux through nanoporous media increases with the decrease of fluid-solid interaction force. In hydrophobic nanoporous media, the nanoscale effect can decrease the gap between water flow resistance in large pores and that in small pores, making the velocity distribution more uniform. In addition, the end effect caused by the bending of streamlines can induce significant additional flow resistance. Neglecting the end effect can greatly overestimate water flow ability. The pore structure also has significant influence on water flow in nanoporous media. With the increase of specific interfacial length, the nanoscale effect increases. Finally, the LB model for oil (octane) flow in quartz nanopores is also established by incorporating the MD simulation results. Oil flow simulation in quartz nanoporous media shows that the conclusions obtained for water flow are also applicable for oil flow. [ABSTRACT FROM AUTHOR]

Solving Navier-Stokes equations for pore-scale porous media flows (PSPMFs) based on imaging data has attracted increasing attention in the community of porous media flows due to a variety of application needs. However, the existing numerical approach is laborious, complex, and error-prone utilizing an ad-hoc coalition of software packages. The multidisciplinary tasks of image processing, computational fluid modeling, and high performance computing together with their integration is overwhelming. We present a unique and powerful computational platform, for PSPMFs with physical and computational advantages. This systematic method is featured with (1) unified mesoscopic modeling, (2) GPU (Graphic Processing Units) parallel computing, and (3) pore-structure upscaling. The multidisciplinary tasks are innovatively integrated into one computational setup thus no software coalition is needed. We use lattice Boltzmann method (LBM) to solve the level-set equation and NS equations successively, thus image segmentation and computational fluid dynamics are seamlessly connected avoiding extra grid and mesh generation or data transfer. The unified LBM modeling enables high efficient GPU parallelism for scalable acceleration. Meanwhile, a new pore-structure upscaling scheme is developed and integrated into downscale the fine grid mesh in the premise of ensuring accuracy. Two application studies demonstrate the reliability, feasibility, and efficiency of this method for PSPMFs. It is believed to be the first-ever integrated and accelerated computational package for studying PSPMFs and it is sustainable. We will introduce more physical models such as interfacial dynamics for multiphase flows, fluid–structure interaction for deformable pore structure, non-Newtonian effects, etc. in the near future. Meanwhile, parallelism based on multiple GPU cards for further acceleration is being investigated. [ABSTRACT FROM AUTHOR]