The Study On Fluid Flow In Micro/Nano Porous Medium By Lattice Boltzmann Method

Low permeability oil is playing important role in China,the classical theory do not fit this situation well.So a new method which named LBM is introduced.Lattice Boltzmann method is a new way for solving fluid dynamics problems.It has strong theoretical background including statistic mechanics and kinetic theory of gases.In the research,the fluid flow in the micro-nano pore is simulated by the LBM.According to the simulation results,we can draw the following conclusions:1 Knudsen number is introduced in the model,different boundary conditions was considered and the velocity distribution in the micro-nano pore was simulated by LBM.In slip flow area,the slip speed does not change;In slip flow area,with the increasing of Knudsen number,velocity profile changes gradually smooth and slip speed increasing,the center line velocity decreased;In the transition flow area,with the increasing of Knudsen number,velocity profile value increased gradually.2 We have discussed the how the fluid viscosity,different pore throat ratio and multi-porosity effect fluid seepage.And we studied the velocity distribution near the centre line and pressure distribution under all kinds of factors along the flow direction.Velocity distribution under the special porosity condition and the change trend of stream line are also considered.These factors revealed the fluid distribution regulations in the micro pore.3 We not only present the flow velocity distribution in the porous media,but also give the results of velocity profile with Knudsen number increased and how the different factors effects the permeability,we draw the conclusions that the Klinkenburge effects obvious when the Knudsen number increased.And when pore size decreased,the speed of fluid near the obstales walls appear 0,it is means the fluid stay quiet.the relationship betweet Kn and porosity fit linership : K=aKn+b,the value of a and b are decreased when the porosity decreased.